marineboy0

Last time I cahnaged the oil from my wife's 1999 ML320 it had sludge in the oil cap.

Oil and filter is changed every 3-4000miles and I have always used a fully synthetic oil either 5-30 or 10W30 since new.

Should I be reading the small print of the class action or do you think this is just an indication of too many short journeys in the cold up here in New England?

Has anyone seen the same?

marineboy0

Forgot to say - the truck has only done 32000m

Darkmann

If you change the oil every 3-4K and you use the right viscosity synthetic, it doesn't matter whether you live in the north pole and just start the car every day and just let it idle, there shouldn't be any sludge build-up. Something's not right. Not even dino oil would develop sludge when changed so frequently. Have it looked at.

marineboy0

My ML320 is allergic to MB dealers (bit like some people and dentists ).

Any idea what could be the cause, anything to look for?

mbtech208

If you're talking about the layer of goo on the inside of the oil cap, thats normal. I can't explain why it builds up on the oil cap, but I guarantee if the oil pan was removed and you looked inside it, everything would look normal. The car should really be driven more, to burn off any impurities and moisture in the oil.

marineboy0

Hi MBTECH204

The goo (or plaque - if I stretch my dental analogy) was a2-3mm thick off-white heavy foam on the underside of the oil cap. However I have never seen this before. But then on the other hand the car had probably never seen such a large number of short shopping trips in such cold weather.

I figure it is crankcase oil vapour that has condensed on this cool part. But am I wrong and I should worry or just see if it re-occurs?