Oil and Oil Filters
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What brand of synthetic oil is best - Amsoil or Mobil?

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January 30, 2010 10:08PM


Amsoil and Mobil are both really good brands. It also depends on what you use the car for. If you like to drive fast? Rev-hard? Drag race? drive in intense heat? Want your engine to last longer? don't want to change your oil as often? then Amsoil is the way to go. sure it is a lot more expensive than Mobil. But the quality of oil is much, much better. I recommend Mobil for everyday driving. but if you're performance minded like me... Amsoil has a large variety of different oils and viscountcies.
The writer is correct on all ideas except I say why not stick with the very best for all conditions, what will happen if your car suddenly loses coolant or over heats for various reasons......would you not want the very best protection? I have a friend who ran 500 miles on no water in his S-10 pick-up with Amsoil, no oil will protect that much! Check the web link under motor oils and select 10W-30 to find the oil comparison testing between Amsoil and Mobil 1.

>>>>Both of the above answers appear to be from AMSOIL representatives. They are biased, and incorrect.

A vast majority of drivers will notice no difference between running a fully synthetic oil over a semi synthetic. Regular oil changes are necessary on both, though you can go slightly longer in between oil changes with the synthetic oil.

Remember, your engine produces roughly the same amount of oil contaminants, regardless of what oil you use. These contaminants include unburnt fuel from cold start-up, the results of incomplete, or poor combustion, and normal carbon buildup. Your oil filter clogs at the same rate, regardless, so regular oil changes are necessary on both.

It is relevant to mention that the more expensive oil filters (such as an amsoil filter) ARE capable of filtering smaller particulate contamination, but due to this design, can actually plug up FASTER than your average manufacturer-specified oil filter. For that I reason, I always recommend to my customers and friends that they use a reputable STANDARD oil filter in all cases.

FINALLY, I would like to address the standard "My Truck Went 500 Miles Without Coolant" statement. Let me first inform you that I am a ASE Master Auto Tech with more than a decade of experience. Secondly, I am an Automotive Engineer with more than 5 years of relevant industry experience.
If you run ANY engine without coolant to the point that it overheats, you are doing PERMANENT damage NO MATTER WHAT OIL YOU RUN.
See, cars have these things called head gaskets - Overheating virtually ALL modern vehicles for any extended period of time (ie more than, say, a MINUTE) WILL result in a bad head gasket.
Furthermore, excessive heat causes a plethora of other severe problems that NO OIL WILL PREVENT, such as PERMANENTLY damaged pistons, cylinders, and rings.

Neither AMSOIL, nor ANY OTHER OIL will protect your engine if you don't take care of it.
There is no substitute for regular oil changes.

Buy what's cheap, if you *must* run a synthetic then buy what is economical for you.

I am not saying that AMSOIL isn't better in CERTAIN, SPECIAL situations - Like racing. I realize there are a lot of people that swear by it in the racing industry - But remember something. Racing engines are a *completely* different breed of engines - They make massive amounts of power, and generate a LOT of heat that is concentrated much differently than a passenger car engine. They also cna run at much higher RPM's, and experience completely different pressure differentials in the crankcase. These are all things that amsoil *might* be better for, but quite honestly, if that *were* the case, it seems that AMSOIL would be citing data from tests, instead of spreading stories like "My friends cousins brother went 500 miles with no coolant because he had AMSOIL".

Yeah. That guy went 500 miles. And then never went again, because that engine was 100% JUNK if that story is true. NO water-cooled internal combustion engine will go even 50 miles without coolant - You can take my word for it. It's true.

>>Those "tests" are a joke - They were performed by Amsoil, and not an unbiased third party. Of COURSE they are going to "show" that their oil is the "best" - Just because you followed ASTM test standards doesn't mean you didn't "design" the test procedure to make sure your oil came out on top.
Furthermore, REGARDLESS of whether amsoil outperforms mobil 1 or not, both oils would far exceed manufacturer specifications for standard motor oil - If changed regularly, engines WILL run on standard motor oil INDEFINITELY - So what's the point to spending all the extra $$$ on Amsoil/Mobil for the standard consumer? Oh wait, there IS NO point to it. It's your standard marketing scam, sell the customer a product that they DO NOT NEED, with significantly increased profit margin.


Those tests are not a joke. They were performed by world renown SouthWest Research Institute in San Antonio, using standard ASTM testing that anyone can duplicate, yet no one has disputed. The extra money you spend for AMSOIL can buy you up to 50,000 mile/1 year oil change intervals, where Mobil 1 does not. This is why the Texas State Police, Texas Parks and Wildlife, and other huge fleets save time and money with AMSOIL.