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)