Choosing the best motor oil is a topic that comes up frequently in discussions between motoheads, whether they are talking about motorcycles or cars. The following article is intended to help you make a choice based on more than the advertising hype.
Oil companies provide data on their oils most often referred to as "typical inspection data". This is an average of the actual physical and a few common chemical properties of their oils. This information is available to the public through their distributors or by writing or calling the company directly. I have compiled a list of the most popular, premium oils so that a ready comparison can be made. If your favorite oil is not on the list get the data from the distributor and use what I have as a data base.
This article is going to look at six of the most important properties of a motor oil readily available to the public: viscosity, viscosity index (VI), flash point, pour point, % sulfated ash, and % zinc.
Viscosity is a measure of the "flowability" of an oil. More specifically, it is the property of an oil to develop and maintain a certain amount of shearing stress dependent on flow, and then to offer continued resistance to flow. Thicker oils generally have a higher viscosity, and thinner oils a lower viscosity. This is the most important property for an engine. An oil with too low a viscosity can shear and loose film strength at high temperatures. An oil with too high a viscosity may not pump to the proper parts at low temperatures and the film may tear at high rpm.
The weights given on oils are arbitrary numbers assigned by the S.A.E. (Society of Automotive Engineers). These numbers correspond to "real" viscosity, as measured by several accepted techniques. These measurements are taken at specific temperatures. Oils that fall into a certain range are designated 5, 10, 20, 30, 40, 50 by the S.A.E. The W means the oil meets specifications for viscosity at 0 F and is therefore suitable for Winter use.
The following chart shows the relationship of "real" viscosity to their S.A.E. assigned numbers. The relationship of gear oils to engine oils is also shown.
_______________________________________________________________
| |
| SAE Gear Viscosity Number |
| ________________________________________________________ |
| |75W |80W |85W| 90 | 140 | |
| |____|_____|___|______________|________________________| |
| |
| SAE Crank Case Viscosity Number |
| ____________________________ |
| |10| 20 | 30 | 40 | 50 | |
| |__|_____|____|_____|______| |
______________________________________________________________
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42
viscosity cSt @ 100 degrees C
Multi viscosity oils work like this: Polymers are added to a light base (5W, 10W, 20W), which prevent the oil from thinning as much as it warms up. At cold temperatures the polymers are coiled up and allow the oil to flow as their low numbers indicate. As the oil warms up the polymers begin to unwind into long chains that prevent the oil from thinning as much as it normally would. The result is that at 100 degrees C the oil has thinned only as much as the higher viscosity number indicates. Another way of looking at multi-vis oils is to think of a 20W-50 as a 20 weight oil that will not thin more than a 50 weight would when hot.
Multi viscosity oils are one of the great improvements in oils, but they should be chosen wisely. Always use a multi grade with the narrowest span of viscosity that is appropriate for the temperatures you are going to encounter. In the winter base your decision on the lowest temperature you will encounter, in the summer, the highest temperature you expect. The polymers can shear and burn forming deposits that can cause ring sticking and other problems. 10W-40 and 5W-30 require a lot of polymers (synthetics excluded) to achieve that range. This has caused problems in diesel engines, but fewer polymers are better for all engines. The wide viscosity range oils, in general, are more prone to viscosity and thermal breakdown due to the high polymer content. It is the oil that lubricates, not the additives. Oils that can do their job with the fewest additives are the best.
Very few manufactures recommend 10W-40 any more, and some threaten to void warranties if it is used. It was not included in this article for that reason. 20W-50 is the same 30 point spread, but because it starts with a heavier base it requires less viscosity index improvers (polymers) to do the job. AMSOIL can formulate their 10W-30 and 15W-40 with no viscosity index improvers but uses some in the 10W-40 and 5W-30. Mobil 1 uses no viscosity improvers in their 5W-30, and I assume the new 10W-30. Follow your manufacturer's recommendations as to which weights are appropriate for your vehicle.
Viscosity Index is an empirical number indicating the rate of change in viscosity of an oil within a given temperature range. Higher numbers indicate a low change, lower numbers indicate a relatively large change. The higher the number the better. This is one major property of an oil that keeps your bearings happy. These numbers can only be compared within a viscosity range. It is not an indication of how well the oil resists thermal breakdown.
Flash point is the temperature at which an oil gives off vapors that can be ignited with a flame held over the oil. The lower the flash point the greater tendency for the oil to suffer vaporization loss at high temperatures and to burn off on hot cylinder walls and pistons. The flash point can be an indicator of the quality of the base stock used. The higher the flash point the better. 400 F is the minimum to prevent possible high consumption. Flash point is in degrees F.
Pour point is 5 degrees F above the point at which a chilled oil shows no movement at the surface for 5 seconds when inclined. This measurement is especially important for oils used in the winter. A borderline pumping temperature is given by some manufacturers. This is the temperature at which the oil will pump and maintain adequate oil pressure. This was not given by a lot of the manufacturers, but seems to be about 20 degrees F above the pour point. The lower the pour point the better. Pour point is in degrees F.
% sulfated ash is how much solid material is left when the oil burns. A high ash content will tend to form more sludge and deposits in the engine. Low ash content also seems to promote long valve life. Look for oils with a low ash content.
% zinc is the amount of zinc used as an extreme pressure, anti- wear additive. The zinc is only used when there is actual metal to metal contact in the engine. Hopefully the oil will do its job and this will rarely occur, but if it does, the zinc compounds react with the metal to prevent scuffing and wear. A level of .11% is enough to protect an automobile engine for the extended oil drain interval, under normal use. Those of you with high revving, air cooled motorcycles or turbo charged cars or bikes might want to look at the oils with the higher zinc content. More doesn't give you better protection, it gives you longer protection if the rate of metal to metal contact is abnormally high. High zinc content can lead to deposit formation and plug fouling.
Listed alphabetically --- indicates the data was not available
Brand VI Flash Pour %ash %zinc 20W-50 AMSOIL 136 482 -38 <.5 --- Castrol GTX 122 440 -15 .85 .12 Exxon High Performance 119 419 -13 .70 .11 Havoline Formula 3 125 465 -30 1.0 --- Kendall GT-1 129 390 -25 1.0 .16 Pennzoil GT Perf. 120 460 -10 .9 --- Quaker State Dlx. 155 430 -25 .9 --- Red Line 150 503 -49 --- --- Shell Truck Guard 130 450 -15 1.0 .15 Spectro Golden 4 174 440 -35 --- .15 Spectro Golden M.G. 174 440 -35 --- .13 Unocal 121 432 -11 .74 .12 Valvoline All Climate 125 430 -10 1.0 .11 Valvoline Turbo 140 440 -10 .99 .13 Valvoline Race 140 425 -10 1.2 .20 Valvoline Synthetic 146 465 -40 <1.5 .12 20W-40 Castrol Multi-Grade 110 440 -15 .85 .12 Quaker State 121 415 -15 .9 --- 15W-50 Chevron 204 415 -18 .96 .11 Mobil 1 170 470 -55 --- --- Mystic JT8 144 420 -20 1.7 .15 Red Line 152 503 -49 --- --- 5W-50 Castrol Syntec 180 437 -45 1.2 .10 .095 % Phosphor Quaker State Synquest 173 457 -76 --- --- Pennzoil Performax 176 --- -69 --- --- 5W-40 Havoline 170 450 -40 1.4 --- 15W-40 AMSOIL 135 460 -38 <.5 --- Castrol 134 415 -15 1.3 .14 Chevron Delo 400 136 421 -27 1.0 --- Exxon XD3 --- 417 -11 .9 .14 Exxon XD3 Extra 135 399 -11 .95 .13 Kendall GT-1 135 410 -25 1.0 .16 Mystic JT8 142 440 -20 1.7 .15 Red Line 149 495 -40 --- --- Shell Rotella w/XLA 146 410 -25 1.0 .13 Valvoline All Fleet 140 --- -10 1.0 .15 Valvoline Turbo 140 420 -10 .99 .13 10W-30 AMSOIL 142 480 -70 <.5 --- Castrol GTX 140 415 -33 .85 .12 Chevron Supreme 150 401 -26 .96 .11 Exxon Superflo Hi Perf 135 392 -22 .70 .11 Exxon Superflo Supreme 133 400 -31 .85 .13 Havoline Formula 3 139 430 -30 1.0 --- Kendall GT-1 139 390 -25 1.0 .16 Mobil 1 160 450 -65 --- --- Pennzoil PLZ Turbo 140 410 -27 1.0 --- Quaker State 156 410 -30 .9 --- Red Line 139 475 -40 --- --- Shell Fire and Ice 155 410 -35 .9 .12 Shell Super 2000 155 410 -35 1.0 .13 Shell Truck Guard 155 405 -35 1.0 .15 Spectro Golden M.G. 175 405 -40 --- --- Unocal Super 153 428 -33 .92 .12 Valvoline All Climate 130 410 -26 1.0 .11 Valvoline Turbo 135 410 -26 .99 .13 Valvoline Race 130 410 -26 1.2 .20 Valvoline Synthetic 140 450 -40 <1.5 .12 5W-30 AMSOIL 168 480 -76 <.5 --- Castrol GTX 156 400 -35 .80 .12 Chevron Supreme 202? 354 -46 .96 .11 Chevron Supreme Synt. 165 446 -72 1.1 .12 Exxon Superflow HP 148 392 -22 .70 .11 Havoline Formula 3 158 420 -40 1.0 --- Mobil 1 165 445 -65 --- --- Mystic JT8 161 390 -25 .95 .1 Quaker State 165 405 -35 .9 --- Red Line 151 455 -49 --- --- Shell Fire and Ice 167 405 -35 .9 .12 Unocal 151 414 -33 .81 .12 Valvoline All Climate 135 405 -40 1.0 .11 Valvoline Turbo 158 405 -40 .99 .13 Valvoline Synthetic 160 435 -40 <1.5 .12
All of the oils above meet current SG/CD ratings and all vehicle manufacture's warranty requirements in the proper viscosity. All are "good enough", but those with the better numbers are icing on the cake.
The synthetics offer the only truly significant differences, due to their superior high temperature oxidation resistance, high film strength, very low tendency to form deposits, stable viscosity base, and low temperature flow characteristics. Synthetics are superior lubricants compared to traditional petroleum oils. You will have to decide if their high cost is justified in your application.
The extended oil drain intervals given by the vehicle manufacturers (typically 7500 miles) and synthetic oil companies (up to 25,000 miles) are for what is called normal service. Normal service is defined as the engine at normal operating temperature, at highway speeds, and in a dust free environment. Stop and go, city driving, trips of less than 10 miles, or extreme heat or cold puts the oil change interval into the severe service category, which is 3000 miles for most vehicles. Synthetics can be run two to three times the mileage of petroleum oils with no problems. They do not react to combustion and combustion by-products to the extent that the dead dinosaur juice does. The longer drain intervals possible help take the bite out of the higher cost of the synthetics. If your car or bike is still under warranty you will have to stick to the recommended drain intervals. These are set for petroleum oils and the manufacturers make no official allowance for the use of synthetics.
Oil additives should not be used. The oil companies have gone to great lengths to develop an additive package that meets the vehicle's requirements. Some of these additives are synergistic, that is the effect of two additives together is greater than the effect of each acting separately. If you add anything to the oil you may upset this balance and prevent the oil from performing to specification.
The numbers above are not, by any means, all there is to determining what makes a top quality oil. The exact base stock used, the type, quality, and quantity of additives used are very important. The given data combined with the manufacturer's claims, your personal experience, and the reputation of the oil among others who use it should help you make an informed choice.
PART 1: ARE OIL CHANGES REALLY NECESSARY?
I believe the whole point of using a premium synthetic oil is peace of mind. I like knowing that I can trust the oil in my car to protect my engine. I like knowing that 300,000 miles down the road, I won't necessarily have to start looking for another vehicle (unless I'M ready). I also like knowing that when 20,000 miles rolls around, I still have a few thousand miles left to find time to change the oil.
Now, you're probably saying to yourself, "This guy is nuts! There's no way that an oil could possibly last for 20,000 miles."
Well, if you don't mind, I'd like to take a little time to, first of all, prove that I'm not in need of psychiatric care. And secondly, I hope that you'll allow me to explain why I believe that a premium synthetic oil CAN last for 20,000 miles or more.
I used to be a pretty regular 3,000 mile oil changer. I had a very hard time believing that an oil could possibly last longer than 5,000 or at best 7,000 miles. Changing at 3,000 miles was very safe and "assured" me of no mechanical breakdowns.
When I started looking at synthetics, my perspective changed a little. I figured, if I was going to go out and buy a $20,000 new car, I wanted to get the most for my money. Just protecting against breakdown for a couple hundred thousand miles wasn't enough. I don't take my car to the mechanic and hope he doesn't break it. I take my car to the mechanic so that he can make it better.
The same can be true of your oil. Let's talk about oil changes
first. If it's necessary to change oil every 3,000 to 5,000 miles, then so be it. We should just do it, and accept that it's an integral part of keeping our vehicles from breaking down.
But, if it's not necessary, why do it? Just because our Dad did? My Dad used to listen to 8-track tapes too. Now we've got these nifty little CD's that sound clear as a bell and last pretty much forever. Am I going to listen to 8-track tapes? Probably not.
I don't change my oil every 3,000 miles anymore either.
There are only a few basic reasons why it is necessary to change your oil, and they all, in the end, have to do with decreased protection of your engine and decreased performance. If these elements can be minimized, then there would be little or no reason to change the oil.
PART 2: MOTOR OIL BREAKDOWN: WHAT REALLY CAUSES IT?
First off, all oil breaks down. That generally will include basestocks and additives. Without focusing on performance characteristics, the most significant difference from one oil to another is how quickly breakdown occurs. Although there are many factors that contribute to the breakdown of an oil, heat is one of the most important. Depletion and decreased effectiveness of oil additives is also important, but that will be discussed later.
Petroleum oil begins to break-down almost immediately. A high quality synthetic, on the other hand, can last for many thousands of miles without any significant reduction in performance or protection characteristics. Synthetics designed from the right combination of basestocks and additives can last almost indefinitely with the right filtration system.
As alluded to above, the first major difference between petroleum and synthetic oil is heat tolerance. Flash point is the temperature at which an oil gives off vapors that can be ignited with a flame held over the oil. The lower the flash point the greater tendency for the oil to suffer vaporization loss at high temperatures and to burn off on hot cylinder walls and pistons.
The flash point can be an indicator of the quality of the base stock used. The higher the flash point the better. 400 degrees F is the absolute MINIMUM to prevent possible high consumption.
Today's engines are expected to put out more power from a smaller size and with less oil than engines of the past. Therefore, the engines run much hotter than they used to. That puts an increased burden on the oil.
Even the best petroleum oils will have flash points only as high as 390 and 440 degrees F. Some actually have flashpoints as low as 350 degrees. For today's hot running engines, this is not nearly enough protection. Just about any synthetic you come across will have a flashpoint over 440 degrees. Premium synthetics can have flashpoints over 450 degrees with some even reaching as high as 500 degrees. That's a big difference.
As a result, I think that it's quite obvious that these high- tech oils offer a substantial benefit when it comes to potential breakdown due to burn-off. Nevertheless, even though synthetics are MUCH less prone to burn-off than are petroleum oils, there is still some burn-off during extremely high temperature operation.
Thus, it becomes important to discuss the manner in which petroleum and synthetic oils burn off. As a refined product, petroleum oil molecules are of varying sizes. Thus, as a petroleum oil heats up, the smaller, lighter molecules begin to burn off first.
Since the ash content in many petroleum oils is higher than synthetics, deposits and sludge are left behind to coat the inside of your engine. Detergent and dispersant additives are used to keep these deposits to a minimum, but only so much can be done. Unless you're changing a petroleum oil every 2,000 to 3,000 miles some deposits are going to be left behind.
In addition, as smaller particles burn off, the larger, heavier molecules are all that is left to protect the engine. Unfortunately, these larger particles do not flow nearly as well and tend to blanket the components of your engine which only exacerbates the heat problem.
Synthetic oils, on the other hand, because they are not purified, but rather designed within a lab for lubrication purposes, are comprised of molecules of uniform size and shape. Therefore, even if a synthetic oil does burn a little, the remaining oil has the nearly the same chemical characteristics that it had before the burn off. There are no smaller molecules to burn-off and no heavier molecules to leave behind.
Moreover, many synthetics have very low ash content and little if any impurity. As a result, if oil burn-off does occur, there is little or no ash left behind to leave sludge and deposits on engine surfaces. Obviously, this leads to a cleaner burning, more fuel efficient engine.
As a side note (as it really has little bearing on when to change your oil), synthetics do a much better job of "cooling" engine components during operation. Because of their unique flow characteristics, engine components are likely to run 10 to 30 degrees cooler than with petroleum oils. This is important, because the hotter the components in your engine get, the more quickly they break down.
WHAT ABOUT THE ARCTIC FREEZE?
This is an issue that some people really don't think about when it comes to oil changes. Most people understand that at cold temperatures, an oil tends to thicken up, and many people know that synthetics do a better job of staying fluid. However, many people don't realize why petroleum oils tend to thicken up. More importantly, though, they don't realize that this thickening process can wreak havoc on their oil.
You see, because most petroleum oils contain paraffins (wax), they tend to thicken up considerably in cold temperatures. Therefore, in order to produce a petroleum oil that will perform adequately in severe cold temperatures, additives called pour point depressants must be used in high quantities. These additives are designed to keep the wax components of a petroleum oil from crystallizing. This maintains decent flow characteristics in cold weather for easier cold starts.
In areas where the temperature remains below zero for any period of time, these additives are used up very quickly because petroleum oils are so prone to wax crystallization. As a result, the oil begins to flow less easily in cold weather temperatures. Of course, the result is harder cold starts and tremendously increased engine wear. Thus, the oil must be changed in order to provide the cold weather engine protection which is necessary.
Synthetic oils, on the other hand, contain no paraffins. Therefore, they need NO pour point depressant additives. In addition, even without these additives, synthetics flow at far lower temperatures than petroleum oils. For instance, very few petroleum oils have pour points below -30 degrees F. Many synthetic oils, without any pour point depressants, have pour points below -50 degrees F. That's a big difference. There is, in fact, one oil on the market that has a pour point of -76 degrees F.
Since synthetics do not have any pour point depressants, there is no chance of these additives breaking down or being used up over time. There are no additives to break down. Therefore, synthetic oils maintain their cold temperature flow characteristics for a very long time. As a result, there is one less reason to change the oil if using synthetic as opposed to petroleum.
In addition, another part of cold weather driving that is extremely tough on an oil is condensation. Because it is so cold, it takes a fairly long drive to get the engine warm enough to burn off the condensation that occurs inside the engine. As a result, vehicles routinely driven short distances in cold weather will build up condensation within the oil. If left to do its dirty work, this water would cause acids to build up within the oil and corrosion would begin within your engine.
So, there are additives in the oil which are designed to combat these acids. Generally, the TBN value of an oil will be a good determination of how well and for how long an oil will be able to combat these acids. Most petroleum oils have TBN numbers around 5. Most synthetics have TBN levels over 8 or 9. Premium synthetic oils (especially those designed specifically for extended oil drains) will have TBN numbers around 11 to 14. This allows for much better acid control for a much longer period of time, thus decreasing the need for an oil change due to cold temperature condensation.
PART 3: WHAT ABOUT ADDITIVE DEPLETION?
First of all, I need to make it abundantly clear that I am not speaking of "Miracle Oil Additives" such as Duralube, Prolong and the like, when I refer to oil additives. I am speaking of the additives that are in your oil right from the original bottle that you pulled off the shelf.
Many people swear by these "extra" Miracle Additives, but I am a firm believer in independent lab results. Every independent test I've seen regarding special oil additives such as those mentioned above has given no indication that they provide ANY measure of increased engine protection. In fact, in some cases they may even increase engine wear.
However, this is a whole other story that deserves a complete article. So, for the sake of remaining on topic, I am going to return to the article at hand and leave you to study this oil additive issue a little further on your own.
It is true that the additives in many oils begin breaking down after only a few thousand miles. What needs to be recognized is that there are different quality "grades" of additives just as there are different quality grades of just about any other product that you buy. There are also different combinations of additives that tend to work for better and for longer when combined than when used individually.
Making a blanket statement that additives in oil die after only 2 to 3,000 miles is like saying that automobile tires will only last for 30,000 miles. To be sure, there are plenty of tires on the market that can only last for 30,000 miles, and then they're toast. But, there are many tires on the market nowadays that will last over 75,000 miles.
The same scenario holds true for motor oils. Many oil companies are using the same additives in their oils as all of the other companies because they are cheap. That's why the oil costs less. You get what you pay for. If they were willing to spend the money on top-quality additive packages for their oils, every synthetic on the market would be recommended for extended drain intervals, and they would all be more expensive. The technology has been around for years. The problem is that oil companies make more money selling a cheaper grade oil and making sure that you change it more often.
1. VISCOSITY RETENTION -- Shear stable viscosity index improvers help premium synthetic motor oils maintain their viscosity in the range appropriate to each grade over extended drain use. Conventional oils formulated with easily sheared viscosity index improvers often drop out of viscosity specification relatively quickly -- sometimes even before the end of a 3,000-mile oil drain interval. Viscosity loss leaves oils incapable of protecting engines from metal to metal contact and wear in high temperatures.
NOTE: It was mentioned earlier that petroleum oils tend to thicken due to burn-off. The statement above is not contradictory to that. It just indicates that petroleum oil is vulnerable to two opposing types of breakdown, which, in the end, render the oil basically useless for lubrication purposes.
2. CONTAMINANT CONTROL -- Dispersants keep contaminants, including combustion by-products, suspended in oil. The rate of dispersant depletion depends on the motor oil's additive treat- rate and the oil's contaminant load. Premium synthetic motor oils are formulated with high additive treat rates specifically to allow extended drain intervals.
3. ACID CONTROL -- Total Base Number (TBN) describes the acid neutralization ability of an oil, with higher TBN oils providing longer lasting acid neutralization. Most passenger car motor oils are formulated with TBN of 5 to 7. Many synthetic motor oils are formulated with 9-11 TBN or higher. The result: longer and better acid neutralization capability allowing for extended drain use.
PART 4: HOW DOES OIL CONTAMINATION OCCUR?
There is also the issue of contamination. Oil will be contaminated in three major ways. One will be through debris that comes in through the air intake. Once it makes it through the air filter, it ends up in your oil. Once in your oil, it starts damaging your engine.
The second source of contamination will be metal shavings from the inside of your engine. The lesser the quality of the oil, the higher percentage of these shavings because there will be more metal to metal contact inside the engine.
The third source of contamination will be from combustion by- products. Combustion by-products will generally raise the acidity of your oil, which causes corrosion in your engine. In addition, they will be left behind as the engine oil burns off and will collect on the inside of your engine as deposits. To maintain the viability of your oil as well as protection of the engine, the contaminants have to be removed/neutralized.
One of the best ways to help with this process is to keep most of the contaminants from ever getting inside the engine in the first place. That's where your air filter comes in. Conventional paper air filters are pretty worthless. How many times have you removed your air filter for replacement only to find that you could write your name in the dust that collected around the air intake? That's just the stuff that was left behind. Imagine the amount that actually ended up inside the engine.
Part of the problem is that traditional paper filters do not fit all that snugly in the air intake compartment. They've improved, but they're still not great. More importantly, though, they let way too much debris shoot right through the filter element itself. As a side-note, they do not provide for very good air flow either.
You see, as a compromise to allow enough air flow for your engine to run "properly", surface type air filtration media have to allow certain sized particles to flow through. If they made the filtration media any more tightly woven, not enough air would pass through quickly enough to keep your vehicle running.
As a result, most paper filters won't catch anything smaller than about 20 to 40 microns with any real efficiency. In most cases, the more expensive the filter, the lower the micron level of filtration - and the lower the better, of course.
20 to 40 microns is pretty small. A human hair is about 100 microns in diameter. The problem is that 60% of engine wear is caused by particles between 5 and 20 microns (most likely because there is so much more of it). If you don't keep that stuff out, it'll eat away at your engine.
Consider an alternative air filtration device which is more like a sponge (actually, it's foam). Because foam is "squishy" it can be made slightly larger than the air intake compartment so that when installed it fits very snug with no room for air to by-pass the filtration unit.
In addition, it has millions of "tiny" channels through which air can flow, but these channels are not straight channels. They twist and turn through the filtration media. Air can pass through easily because these "tiny" channels are actually much larger than the channels through the paper filter we just discussed. This is possible because the paper filter only has one chance to get the dirt. This foam media has multiple opportunities to catch the dirt.
You see, as the air travels through these winding channels, it can turn this way and that with ease. However, the dirt particles that the air is carrying travel in a straight line until they hit something. Obviously, at every turn, the debris within the air hits a "wall". You say, "Well, that's great, but why doesn't that dirt just bounce off the wall and keep right on going?" Good point. I tell you what, why don't we put a tacky substance in the foam so that when debris hits these "walls" it's stuck there like a fly to one of those sticky tapes. You say, "Yeah, that would work!"
Not only will it work, it will work far better than the paper air filter discussed above. Because of the depth-type nature of the foam filter AND the added tack oil, it will remove most particles larger than 5 to 10 microns. Thus, most of the harmful stuff is stopped before it ever reaches the inside of the engine.
Now, we've established that such a filtration media would seal up the intake compartment, should have better air flow, and we've established that it has more opportunities to catch the dirt, so probably less dirt makes it into the engine. The next question should be, will it hold as much dirt as the paper filter?
Well, of course it will. It's much thicker than a paper filter, and, because of the nature of the foam media, has a virtually limitless surface area over which to collect dirt. In fact, the more dirt it collects, the better the filtration (with minimal reduction in air flow). It's also much more durable than paper, so it NEVER needs to be replaced. Just wash it once a year, re- oil it and put it back in the vehicle.
PART 5: ENGINE WEAR PARTICLES CAUSE OIL CONTAMINATION
Ok, so we've taken care of the air intake, but what about metal particles from engine component wear? Well, there are a couple of things going on here that lead to better protection from a synthetic oil. One aspect that proves to be very important is cold weather starts. Now, all of us have heard about cold weather starts for years from oil additive manufacturers. We've all heard, "Just put our additive in your crankcase and it will form an impenetrable layer over engine components that will protect your engine against wear, especially at start-up. In fact, it's so good, you could even drain the oil from your engine and drive it around the track a million times at 60 mph."
Hogwash. Just about all of the companies that have made claims like this over the years have been brought up on charges by the FTC. They're full of it. However, they were right about one thing. Cold-weather starts are killing your engine. Consider this:
The pour point of an oil is 5 degrees F above the point at which a chilled oil shows no movement at the surface for 5 seconds when inclined. That's tech-talk which basically means that the pour point of an oil is the point at which it ceases to be "pourable". This measurement is especially important for oils used in the winter.
A borderline pumping temperature is given by some manufacturers. This is the temperature at which the oil will pump and maintain "adequate" oil flow and pressure within an engine. This is not provided by a lot of the manufacturers, but generally seems to be about 20 degrees F above the pour point. So, the lower the pour point the better.
Most petroleum oils have pour points in the range of -15 to -35 degrees F. That means that their borderline pumping temperature is, at best, around -15 degrees F and probably closer to 5 to 10 degrees F. So, if you're running a petroleum oil, don't expect to go out and start your car at 0 degrees and have it purr like a kitten. It's going to spit and sputter and kick and scream for a few minutes.
Why do you think that is? It's not getting any oil up into the engine. It's like trying to suck molasses through a tiny straw in an Alaskan January. There's literally nothing keeping the metal components in your engine from tearing each other apart. Every time you start your engine in conditions like this, your engine dies a little bit more.
Synthetic oils, on the other hand, routinely have pour points around -40 degrees or colder. Some have pour points as low as - 60 to -70 degrees F. Granted, there are very few of us who will ever have to start our car at this temperature, but imagine how well these oils lubricate at -20, if it they still flow at -70.
Now, I know that some of you live in areas where you almost never see temperatures under freezing. For you folks, the pour point of your oil may be a little less important, but it still serves to prove a point about the protection differences between petroleum oils and synthetics.
In addition, lets get back to that impenetrable barrier over your engine components that oil additive manufacturers sputter about all the time. Although, there is no scientific testing that proves this will really occur in actual automotive applications when using an oil additive, synthetic oils do provide something similar to this.
Generally, a thin film of synthetic oil will remain on engine components for days after it was last run. Petroleum oils tend to drain back down to the oil pan very quickly, leaving no oil film to protect your engine at start-up. Many auto techs and backyard mechnics can attest to this after doing engine tear- downs. Those using synthetic oil generally will have a thin film of oil left on components even if the engine has been sitting for awhile.
It's certainly not impenetrable, and I wouldn't go draining your oil after installing 6 quarts of synthetic just to see if your engine still runs, but it does serve a purpose. Your engine should virtually NEVER see metal to metal contact, whether in hot or cold climates. That's something that a petroleum oil can't do.
In addition, because of the higher film strength and better lubricity characteristics of synthetic oils, they routinely perform better on standardized ASTM wear scar tests. This would indicate a higher level of engine protection and would certainly lead to fewer engine wear particles in an engine. Hence, fewer contaminants in the oil to necessitate changing it.
PART 6: COMBUSTION BY-PRODUCTS CAUSE ENGINE DAMAGE
Only one type of contaminant left to discuss: combustion by- products. These little buggers can wreak havoc in an engine. Not only can they form deposits on the inside of an engine which will rob it of performance and, ultimately, life expectancy, they will also tend to raise the acidity of the lubricant.
Higher acidity levels in your oil can lead to severe corrosion and break-down of engine components. In turn, this break-down leads to more oil contaminants and the necessity for an oil change.
Three things keep these contaminants in check: the TBN of the oil, high efficiency oil filtration and tight ring seal. The most important of these three is ring seal. If the number of combustion by-products entering your oil can be reduced, there will be less necessity to remove or neutralize them.
Poor ring seal allows combustion by-products to pass from the combustion chamber into the crankcase where they contaminate the oil. Tight ring seal keeps them out. Synthetic motor oils encourage a tighter ring seal than petroleum motor oils do.
As we discussed earlier, TBN (total base number) is a measure of how well a lubricant can neutralize acidic combustion by- products. The higher the TBN, the better the protection against these acidic by-products and the longer that protection will last. Hence, the possibility of longer oil drain intervals with oils that have high TBN values.
Oil filtration is the last component that must be discussed when making the case for extended oil drains. The next section in this series addresses this critical component.
PART 7: SYNTHETIC OILS OFFER GREATLY EXTENDED DRAINS
There you have it. If this "little" article doesn't at least get you thinking about switching over to synthetics, I'm not sure what will convince you. I know that this article is a little less technical than it could be. There are many other differences between petroleum and synthetic oils which were not touched on here, but if we had covered those too, this article would have been 50 pages long. Most of the information presented here was meant to deal strictly with the concept of extended drain intervals and why they're possible. If you'd like to learn more about the technical aspects of automotive lubrication and filtration, you might want to consider purchasing "The Motor Oil Bible".
There are a couple of companies out there that are probably good for extended oil drain intervals. I'll speak more about the specific companies in the next chapter. However, since many people use Mobil 1 and believe it to be the best synthetic available (mainly because it is the most recognizable name), I thought I might spend a little time touching on that particular company.
In my opinion Mobil 1 oils are most likely good for 10,000 to 15,000 miles, but the company does not make that recommendation. I have known of many people who do very well running Mobil 1 for these intervals, but it has not been designed specifically for extended drain use. Moreover, the company probably would not back you if you had any mechanical problems resulting from such extended drain use, since they only recommend "manufacturer recommended change intervals".
In light of the information above, I would like to leave you with a few notes of importance. If a synthetic oil is not specifically recommended for extended drain use, and you choose to attempt extended drains, you do so at your own risk. Extended drain synthetic oils must be formulated with special long-life additives and blended basestocks so as to maintain their lubricating properties for an extended period of time.
In addition, in order to get the full benefit from extended drains, it is most beneficial to be using high efficiency oil and air filtration as well. If you are using traditional filtration methods, you will likely have to change your oil more often and will end up with reduced engine protection. If you're going to do it, do it right. It will cost you less in the long run, and probably in the short run too.
PART 8: VERY FEW COMPANIES OFFER EXTENDED DRAINS
Now, you may be saying to yourself, "This is all great, but there is something I just don't understand. If there are oils out there that will last for 25,000 miles - and have been for over 25 years - why am I still being told to change my oil every 3,000 miles? Either someone is lying or someone just doesn't have all of the facts.
Well, I believe that it is a little bit of both. You've probably heard that 3,000 mile oil changes are necessary from friends, family, possibly your mechanic and definitely your local quick lube operator. The problem is, most of them are just reiterating what they've been told for years - and it has served them fairly well.
Most of them simply do not understand lubricants nearly as well as they think they do. Even those mechanics who are brilliant when it comes to automotive engines are not necessarily experts on lubrication. Lubrication technology is much more involved than most of them thinks.
Nobody can know everything, but in order to give people the most accurate advice, it pays to make sure that you have all of the relevant information.
I believe that there are even a large number of quick lube operators that don't know nearly as much about lubricants as they'd like to think. However, I also believe that some of those same quick lube operators that are telling you to change your oil at 3,000 mile intervals might very well be using synthetic oil for extended oil drain intervals in their own vehicles.
It's sad, but true. Oil companies and many quick lube operations know that synthetic oils are capable of extended drain intervals but are too afraid of lost revenue to admit it. In fact, here are a few quotes from different people in the automotive and lubrication industries which should illustrate what I mean:
According to GM's Mike McMillan, "Certainly there is technology available to raise the standard and extend the drain interval without compromising engine durability or removing the performance cushion ... Europe is already at a 9,000 mile drain interval and is seriously considering twice that". Of course, you have to remember that most vehicles in Europe are using synthetic oil.
Most other auto manufacturers seem to agree with Mr. McMillan. In the May 1996 issue of Lubes 'n' Greases representatives from the three major US auto makers detailed how lack of knowledge about available lubricant technology led to an unsatisfactory PCMO (Passenger Car Motor Oil) upgrade.
In "GM's Tough Agenda for Lubes," Lubes 'n' Greases reports that extended drains are a customer service issue. "...We're very concerned about engine durability and oil drain intervals particularly as they impact reducing the amount of maintenance our customers are required to perform. Customers want to minimize their vehicle maintenance time and changing engine oil is their single biggest remaining maintenance item. Addressing that issue is very important to us."
Even quick lube operations know that the technology exists to extend oil drains well beyond the 3,000 mile mark. Some are embracing extended drain technology as a way to increase customer satisfaction as well as company profits by working WITH the improvements in lubrication technology, instead of against them.
Dennis Brooks, Vice President of SpeeDee Oil Change and Tune- Up, implied as much in a statement he made in the November 1996 issue of National Oil & Lube News, a respected periodical in the lubricants industry.
In regard to the extended drain issue Brooks said, "I believe there will be greater potential to move into selling a higher percentage of synthetic oil."
Others in the quick lube industry, however, are running scared. Jim Sapp, Convenient Automotive Services Institute (CASI) president, is quoted in the same article as saying, "For years, Jiffy [Lube] has preached the 3,000 mile or three month oil change interval. And fortunately for us, many motorists take it as gospel. But we need to do more as an industry ... It's not inevitable that intervals will expand to the point where we can no longer stay in business." In other words, it IS possible to continue to keep motorists in the dark about extended drains.
In the October 1996 issue of Lubes 'n' Greases, Quaker State CEO Herbert M. Baum suggests, "We need to go on the offensive. Stop fighting with each other and go forward as a group; fight for regular oil changes. We have to build business as a group, and it's the role of our associations to promote the use of our products."
Nevertheless, Quaker State now is manufacturing and selling an oil which they say can last for 7,500 miles (although they neither recommend nor guarantee those intervals). They're trying to ride the rail and pad their pockets, but eventually a train is going to come along, and they are going to have to choose a side or get bulldozed.
You see, extended drains are happening and have been scientifically proven for nearly 30 years to be safe as long as the oil used has been designed for extended drain use. As of May 2000, I know of only three motor oil manufacturers that actually recommend extended drain intervals for their oils: AMSOIL, NEO and Red Line.
Other synthetic oils are likely to last longer than 3,000 to 5,000 miles (probably closer to 7 to 10,000), but the manufacturing companies do not recommend, nor will they back such practices with any sort of warranty.
AMSOIL recommends and guarantees up to 35,000 miles or one year for most automotive gasoline applications and has recommended slightly shorter 25,000 mile changes since the early 70's. NEO has also been in business since the early 70's and recommends 25,000 miles or one year intervals. Red Line gives a range of 10,000 to 18,000 miles as the recommended change interval, depending upon your driving habits.
Of these three oils, AMSOIL sells for the best price at as little as $5.70 per quart for their 25,000 mile oils or just over $8.00 per quart for the Series 2000 35,000 mile oil. Red Line follows at an average of $7.50 to $8.00 per quart for all of their oils. NEO appears to be the most expensive at close to $10 per quart.
If used for their full recommended drain interval, all of these oils are more economical than an off-the shelf synthetic oils that you find at the local K-Mart, Walmart or Meijer. These typically run about $3.50 to $4.00 per quart but should be changed 3 to 5 times as often.