Ok to use SL rated oil in an SM rated car?

[kschachn]

Or even worse, the ones that claim to see a difference between 0W-20 and 5W-20. Or different brands of the same weight.

A while back I posted an article that showed that gasoline energy density varied 4% even at the same station. The article also described the pitfalls of trying to measure fuel economy outside of a lab/controlled environment. There are just too many variables to get much that is meaningful, unless extraordinary measures are taken.

Originally Posted By: bvance554
Originally Posted By: simple_gifts
by definition if it is less, it is measurable.

Yes thank you. There is one in every crowd. You're not going to measure a difference in fuel economy between 5w-20 and 5w-30.

 

[NHHEMI]

Originally Posted By: SpeedyG75VW
Originally Posted By: gregk24
Exactly what car do you have, the year and engine also. My 2006 Accord takes either 5w20 or 0w20 but the only oil specs are that it has to have The API starburst symbol and it needs to be a "premium detergent oil" nothing about SM SN SL etc.



You know what?? I think you are right. I got a 2007 Fit. I just finished looking through the owner's manual and no where did it say it required "SM" rated oil. Only "API starburst". Now I'm wondering where I got the "SM" idea from......could have sworn it was from the owners manual though........


In 2007 API Starburst oil would have been SM rated. SM replaced SL in 2004.

 

[NHHEMI]

Originally Posted By: HKPolice
I wouldn't use it on newer cars unless you wanna risk ruining your exhaust system.

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=661505

SL has no limit on the % of sulfur so it can clog your cat easier.


Originally Posted By: 00Max00
Originally Posted By: GMorg
I've been running SL in an SM application for 9 years and 108K miles. I'm still waiting on the damage to occur.


When it does occur, prepare to pay hundreds for the cat. Not worth the risk.


Cat damage would only occur if the engine consumed a lot of oil and it will take quite a while for it to damage the cat even then. Your engine has to burn oil for it to damage the cat. As long as the engine is healthy there will be no cat damage from any oil used let alone SL where SM is called for.

 

[KCJeep]

Use it.

 

[Danh]

Originally Posted By: NHHEMI
Originally Posted By: HKPolice
I wouldn't use it on newer cars unless you wanna risk ruining your exhaust system.

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=661505

SL has no limit on the % of sulfur so it can clog your cat easier.


Originally Posted By: 00Max00
Originally Posted By: GMorg
I've been running SL in an SM application for 9 years and 108K miles. I'm still waiting on the damage to occur.


When it does occur, prepare to pay hundreds for the cat. Not worth the risk.


Cat damage would only occur if the engine consumed a lot of oil and it will take quite a while for it to damage the cat even then. Your engine has to burn oil for it to damage the cat. As long as the engine is healthy there will be no cat damage from any oil used let alone SL where SM is called for.


+1. Cars with catalytic converters got along pretty well for nearly 40 years with higher pre-SM levels of phosphorous.

 

[fdcg27]

I'd use the Defy.
As previously noted, cats did just fine on oils with substatially higher allowable metals levels.
Fuel economy?
You won't see any difference.
You have the oil, so you might as well use it.
It won't do any harm.