Hey, Jim!

My wife's 2007 E350T-4M with M272 has very suddenly begun losing massive amounts of oil (three quarts in 275 miles); some is burning, as I see a thicker cloud than I should on startup that dissipates pretty quickly, but there's a massive leak as well, with oil up on top of the engine near the front, which could be the filler cap as you found in your case.

I've had the car to two different indy shops and neither wants to take the time to figure out the problem, just telling me it needs a new engine. After practically begging the second shop to do a compression test, they tell me all six cylinders are at 150 psi, but are claiming that doesn't confirm anything, as it could be the compression rings are fine but the oil rings are shot. Their theory is that it's blowby pushing oil out the dipstick, but I don't see oil on the dipstick tube and if the compression is good I wouldn't think there should be much blowby. There is also a very ugly cyclical noise from somewhere in the engine compartment that they've diagnosed as a piston slap, but I can't say that I've ever heard a piston slap and don't know whether to agree or disagree with them.

Any thoughts on the subject would be welcome.

Best Regards,
Rob

__________________
Robert Fini

'12 ML350 BlueTec, 87k
'06 E320CDI, 270k
'05 T1N Sprinter 2500/Pleasure-Way Plateau TS, 69k
'97 C36AMG, 313k (son's)
'94 E320T, 249k
'93 190E Sportline LE, 168k (daughter's)
'84 190E-2.3/5spd (Stage Rally Racer)
'66 230 W110 Sedan (Barn Find, Vintage Racer build in progress)