Hi,
I just bought a 1986 190d in NYC and drove it to Wisconsin. Before I made the long trip home, I thought an oil change would be good considering I had no idea when it was last changed. I drove about 4 hours to PA with the oil that came with it seeing no problems. ie. oil light never came on and the oil pressure guage went all the way up when driving at 3000 rpm and down when idleing.

About 30 min after getting the oil changed the oil light blinked on and then off. The guage went down from 3 to 2 while there was no change in acceleration. The light came back on for a few minutes. I drove maybe 5 or 10 min at ~3000 rpm with the needle reading 2 instead of 3. The oil light went off and I pulled over.

I thought maybe they didn't put the drain plug in or something at the oil change but i was wrong. Here's the real stumper. According to the dipstick when I checked there was about 2 qts too much oil in the engine. At this point I was very confused as to why the dipstick said too much oil but the engine said not enough pressure. I thought maybe the filter was clogged or in backwards.

I had a place drain 2 qts of oil until the dipstick read max and drove the car back to WI with no problems. But now I'm worried as to why the light came on and the pressure dropped. Could I have blown a seal somewhere? Anyone have any ideas?

Thanks!
Nat

 

You don't say what the pressure is since draining the 2 quarts.

I consider there are two possibilities.

1. Overfilled plus pressure gauge dropped as oil got really warm due to prolonged journey. When the oil light came on it is showing that the system is having trouble maintaining a minimum oil pressure due to bearing/pump wear
2. Water or other fluid is mixing with the oil and causing the level to increase. Oil light came on because "oil" has been diluted with water and isn't able to achieve normal pressure due to different viscosity.

The point you make about the filter being incorrectly fitted is a good one and needs to be eliminated.

Questions are.

Is/does oil level now remain correct?
Have you uised any water?
What is the pressure gauge reading both hot and cold.
Is the engine overheating?

Stuart

 

Thanks for that.

The pressure after draining the 2 qts was back to 3 all the way home.

I think it might be your #2 idea.

Since I posted the topic the water level light has come on. I checked and the water is down. The oil level seems to be up a quarter inch from the level it was drained down to a day ago. The pressure gauge seems to read 3 both hot and cold. The engine doesn' seem to be overheating.

I also noticed when the oil is wiped off the dipstick it soaks in to the rag quickly like water rather than oil. Is there anything else I can do to confirm that this is indeed the problem?

If it is is it fixable? How would I find the leak?

Thanks!
Nat

 

Hi,
Another classic way of detecting water in the oil is whether you have a mayonnaise like deposit on the engine side of the oil filler cap when you remove it.

If so you have a leak between the water and oil systems.

Good news is that this sort of problem is usually fixable but the bad news is that you will have to part strip the engine to correct the problem. Likely culprit is a head gasket.

Only mystery is why the oil pressure went up to 3 after draining some of the "oil" out?? Strange.

Suggest you get the oil and water levels correct and watch what happens for a few days to confirm diagnosis and assuming the worse.

Stuart