Hello All.

How can I tell if my engine is sludging oil? What are the tell tale signs?

hi, check under the oil cap. I found some oil sludge there a while back when I replaced the oil every 6k miles or so. Also check the filter, you will know if sludge is accumulating

The dealer can do an oil consumption test. This entails a dealer oil change ($150) then you drive for a set number of miles.

When you reach the mileage, they check how much oil was consumed. If it is out of spec then you have a problem.

I noticed a heavy sludgy buildup in my oil filler hole. When I had my HB replaced I asked that they perform the test. I’m really glad I did because I had a problem. The dealer rebuilt the engine under warranty, but charged me for a few optional parts that weren’t covered.

good luck

What year ML do you have, and what kind of oil did you use before they rebuilt your engine??

I have a 1998 ML with 129000 miles.

I purchased it used from a realestate agent down in Hilton Head. I got it with 108000 miles but it ran fine and looked great. The previous owner had all the service records from Mercedes so I knew it was taken care of. I'm not sure what oil the dealer initially used but I don't think they started with synthetic. I think Mercedes switched to Mobil 1 later on.

Since I've had it and the rebuild its been Mobil 1 0w40 (I think thats the weight). I change the oil every 5000 miles and it doesn't use a drop between changes now.

Is there a way to figure out if there was a sludging problem in the engine based on the photos of the engine? Or the sludge is accumulated in oil filters only, so you might not see the problem if you open the engine cover?

Also, what are the symptoms of the oil sludge issue in M-class?

__________________
1999 ML320
100,000 miles
77K - engine failure


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