Royal Purple 5w40 in E55
Thread Starter
Senior Member
Joined: Dec 2006
Posts: 325
Likes: 1
From: Miami, FL
2013 E63 AMG
Royal Purple 5w40 in E55
So I purchased my E55 with Mobil 1 0w40 in the engine and it sounded like thin oil at all times. Then I installed the RP 10w40 great oil and better then the Mobil 1, but in the cold Miami mornings 40-60 degrees that AMG upper valve train noise was around until it was fully up to temp. I just changed my oil to RP 5w40 and this is the best oil for our E55’s. From engine start up it is smooth and seems like it helps my car get better MPG which is great since oil is up and gas station prices change everyday like the stock market. My highway MPG was 19-22 with RP 10w40 and now it’s 20-23 with 5w40. My computer would say 19.2 Average now 20.9+. Royal Purple finely made great oil for European cars, Thanks guys.
MBWorld Fanatic!
Joined: Dec 2005
Posts: 2,021
Likes: 3
From: Fort Worth, TX
2011 GL550, 2004 Audi S4 v8
Yea, that's what I just did...Now try putting in Lucas fuel injector cleaner at fillup and watch the gas mileage really go up. 
Oh and by the way...40-60 degrees is beautiful in the mornings.
New England is lucky to get that with the sun up all day.
Oh and by the way...40-60 degrees is beautiful in the mornings.
New England is lucky to get that with the sun up all day.
MBWorld Fanatic!
Joined: Jun 2007
Posts: 1,378
Likes: 4
From: Bloomingdale,IL
2004 W211 E55K, GL550
I wanted to use royal purple but wasn't to sure about it but it sounds good. I Resently tried Elf oil 5W40 weight and Love it MPG is about the same but the car feels alot stronger i do think its better then Mobil 1 but can't say how it would compare to R/P. Im sure both are just as good?
