What weight should I use in synthetic oil for my 03 CLS. The owner's manual recommends 5W20 but I can't seem to find that in Mobil 1's line. Any alternative suggestions?

 

Anything close, like 0-30, 5-30, 10-30, 0-40, 10-40, etc..

 

in the summer I run thicker weight oils like 10w30 and in the winter I run lighter weight oils like 5w30.

the owners manual reccomends the 5w20 because it improves fuel economy or allows for better emmisions or something like that...

 

Thanks for the advice - anybody else care to offer their suggestions?

 

do a search on 5w20

 

Assuming you haven't already done the search, the 5-20 designation is for CAFE mileage standards only. Our same motor one year earlier was listed as using 5-30. Use the Mobile 5-30 and there will be no problems. Many, many people on this forum do.

 

10W 30 is good to well below zero F, so think that will work fine unless you're considering moving to, say.... Fargo or Fairbanks .

FWIW, I have read during my research on which oil to use that you want to keep the viscosity span from low to high to 20 or so, since a larger viscosity span means more polymerized molecules to burn and form deposits, so 5W30 would be best, but...

Best

Jim

 

My ’01 CLS owner’s manual recommended 5w-30 (not 5w-20). It's the same basic engine that’s in the TLS and later CLS (2002 and 2003).

IMO, you would be fine with 5w-20, 5w-30, 0w-20, and 0w-30.

Do yourself a favor and change the oil more often than the factory recommendation, if you are not doing oil testing (once again -- my opinion).

Try some of the good synthetics:

Mobil 1, Amsoil, Redline, etc, etc

Here is a link to Mobil 1 0W-20 (if you want to stick with the low viscosity):

http://www.mobil.com/USA-English/Lub...bil1_0W-20.asp

YMMV