Schaeffers supreme 5w30 for a 5w20 engine?

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Oct 26, 2003
Granville, Ohio
There has been a lot of information posted about why the auto manufacturers specify 5W-20 in the first place. I agree with the school of thought that suggests that the car probably gets slightly better gas mileage with 5W20, and therefore is an easy way for the manufacturers to meet their CAFE (Corporate Average Fuel Economy) requirements mandated by the EPA.

And I also agree with you that an oil such as Schaeffer's Supreme 5W-30 is better for your engine. If it were my car, I'd make the switch.
Schaeffer's official position is to recommend switching to their 5W-30 the day your warranty expires. I'd use the 5W-30 from day-1.

Since you've eliminated warranty concerns, I can only say if it was my vehicle, I'd have no hesitation about switching it to BobZoil 5w30 at the next oil change. Bang for the $$, probably the best oil out there, IMO.
What does the fine print in your owners manual say, is 5W-30 listed as an option? Or is it specifically a no-no like 10W-40 in a lot of earlier GM products?

Schaefers is be licensed by API to produce oils to the latest specs, unlike some of the botique oil manufactuers.

If the oil meets all your other truck manufactuerer's specs, it would be hard for them to refuse coverage on a warranty claim because you used an xW-30 in place of a xW-20.

If you used a lighter oil or an oil that didn't meet their other specs, you could have a problem with a warranty claim that appeared to by oil caused.
In the Used Oil Analysis - Gas Engines subsection there was a Honda which used a XW20 and a 5W30 and the results looked better with the thinner oil.

If I was to use a 5W30, I'd want to use one which was on the thin side or one which tended to shear rapidly down to a 20 weight. Maybe Castrol GTX??

The one report on Schaeffer S7K 5W30 (Bogatyr's Nissan Xterror) I remember had the weight looking rock solid 30 weight after 4,000+ miles of summer driving (mostly highway).

--- Bror Jace
The owners manual does not say that you can not use another grade, it just says SAE 5w20SL "recomended" with no options listed.
As stated before,

#1 - 5w-30 will NOT void the warranty as long as it is an API SL oil.

The company I work for runs Mobil Drive Clean 5w-30 in every gas engine. They used to run Mobil Delvac 15w-40 in everything, but this created warranty issues because it was not a SL rated oil. The local dealer told us that if we continued to run the diesel oil it would void the warranty.

#2 - 5w-20 has shown excellent results in engines up to the Ford V-10. (don't let the 5w-20 basher's convince you that it is bad for your engine. UOA's have shown that a Ford approved 5w-20 does the job quite well.

IMHO, I wouldn't have a problem running Schaeffer's #701 in a Triton engine. I don't believe there are any UOA's with Schaeffer's & these engines, so you may want to run one after the second run with Schaeffer's to see how it is doing. As a rule, Schaeffer's has had very good results in most engines, but don't forget about Patman's LS1 where Schaeffer's continually showed higher than normal lead.
Just wondering how you guys feel about running the supreme 5w30 in my truck that specs a 5w20 oil? I have been running penzoil 5w20 but I am thinking of swithing to Schaeffers due to all the good things I have read about it on this board. Warranty requirements are a non-issue due to the fact that I used to work for the dealership I bought the truck at and they will not give me any hasstles. I did a search but I can not find any uoa's of Schaeffers in my engine. Thanks for any input!
Just for the record, I have no problem with 5w20 oils. If schaeffers made a 5w20 I would certainly run that! I just want to try it because of all the good things I have heard about it, and the price is reasonable. I will do an anylisis after the second interval and post the results.
Just a ditto of a lot of other comments, but the Shaffers 5w30 would be fine in "triton" truck motor that calls for 5w30. They all called for 5w30 to begin with, and nothing has changed internally, so go for it!

I went the opposite route - from 5w30 to 5w20 - and haven't looked back. The numbers are looking very nice!
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