After reading a lot of oil discussions here, I keep falling back on the principle of RTFM. My manual is quite clear on viscosity--20-50 is the recommendation for the temps I drive in with this car (3-season only). 5-30 found its way in there once by error and consumption went way up. MB obviously had certain characteristics in mind in designing the engine, and set their recommendations to match them. Re oil type, the best performance I've had re leaking at 165K is dino old-engine formula, Valvoline in my case, so I'm stickin' with it. For this high-mileage beast with no top end work done yet, and not much needed, frequent changes seem more key than high-tech chemistry. But that's my answer for a high-mileage seasonal-use car--your situation may be different, and it's always "horses for courses".

__________________
Craig Bethune

'97 SL500, 40th anniversary edition

'04 Olds Bravada (SWMBO's)
'06 Lexus ES330
'89 560SL (sold)


SL--Anything else is just a Mercedes.
(Kudos to whoever said it first)

I agree with you. I recently bought a 1991 300CE with 120k miles on it. After I bought it I had all the fluids changed, including the oil. I decided to try Mobil 1 5-30. Big mistake. Oil comsuption went up way high.

Went back to dyno 2-50 and oil consumption dropped down to a little less than a quart every 3k miles. Which is pretty darned good for a high compression engine with 126k miles.

Stick with the info in your owner's manual; look at the detergent qualities of the oil you use and change it often. Dino oil is cheap, and engine overhaul is expensive!

__________________
Current Benzes

1989 300TE "Alice"
1990 300CE "Sam Spade"
1991 300CE "Beowulf" RIP (06.1991 - 10.10.2007)
1998 E320 "Orson"
2002 C320 Wagon "Molly Fox"

Res non semper sunt quae esse videntur

My Gallery

Not in this weather!

I run Delvac 1 5w40 in my old diesels and it seems to work great, I would think the gas engines of similer vintage would like it as well. According to my 603's owners manual 5w40 is recomended for just about all temps.

__________________
2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200

I've seen more than one MB V8 suffer from cam oiling issues when using heavy weight oils. Its not a sludge problem but more a problem of squeezing enough cold thick oil thru the small cam oiler tube holes. May be OK in warmer areas but I wouldn't do it here in Texas in the winter.

I run synthetic in my V8 cars.

However, I read somewhere that you never have to change your oil.