Originally posted by Manya
my 250SE runs fine on 5W40 fully synthetic. No oil leaks
Though a week ago the head cracked. So i'm up for an engine rebuild.
I'm not so sure it runs fine, not if the head cracked! Seriously though, not suggesting that the oil caused it. Sorry to hear of your bad luck.
I think the lighter viscosity oil may help, but is not really the solution to the problem. My 190E also has a couple of lifters that are intermittently noisy until the engine reaches full operating temperature. I have found that the 15W-50 in the engine at present needs more time before the lifters quieten than the previous 10W-40. Lifters are not that expensive and I have every intention of replacing them. It needs a new valve cover gasket anyway and I am also tempted to do something about the blistered and peeling coating on the valve cover.
107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.