84 190e 2.3 Lost oil pressure
 

Noticed the oil pressure did not peg recently. The guage went down to 2 and below at speed. Changed oil and it went back to normal. Wife driving the other day on highway and lost oil pressure. It went to 0 and she pulled over. She said car lost power and she could here valves tapping. She cut it off. Later, I started and oil pressure pegged and was normal again. It ran good and drove car home and ran rpm to 4000 for a test and oil pressure stayed pegged. An hour later I restarted and no oil pressure. Engine sounded stressed and I could here the valves tapping. Checked relief valve and it was ok. Looked at oil filter and it had very small bits of metal. Oil pump? Can I raise the engine a few inches to remove oil pan? Can front cover be removed without removing head? Car is in good condition with 170,000 miles. Oil changed every 3000; 10w-40. I did use 10w-30 just before all this happened. Any recommendations?

I think you are losing or have lost the oil pump. You probably should not consider the car driveable until repaired, because you could do more damage through not having sufficient oil pressure.

Someone more familiar with your engine can help you with the specific questions. I think on some of the 300 series cars in the '80s there were two sections on the oil pan, one of which can be removed while the engine remains in place to change the oil pump. If that's not the case on the 190 series then you'd be lifting the engine somehow.

Good luck - your wife did the right thing - tell her we said she is smart!

Ken300D

Removed the timing chain cover and oil pan (about 12 hours) and found the plastic facing on the timing chain tension had worn and broken off. Parts of plastic blocked oil at the pickup tube and the bits of aluminum in the oil filter were from the bare face of the tensioner being worn by the chain. The oil pump on this engine appeared bullet proof to me. Ordering new parts for re-assembly.

I almost agree that the oil pumps are bullet proof....on my 1990 300CE I noticed that while driving I suddenly lost oil pressure. As luck would have it, the pump seized up internally and the bolt that attaches chain pulley snapped right off. The local shop I go to has never seen that happen before. Thank goodness for the oil pressure guage....now for my 99 ML320 I assume Mercedes feels that oil pressure will never be an issue since there isn't any sensor for oil pressure. They have a oil level sensor, but no oil pressure sensor. Go figure....

Have a safe and happy new year!

I replaced the tensioner rail, gaskets and seal. I did have a problem replacing the harmonic balancer. When I pushed the balancer over the crankshaft, the woodruff key got pushed out and against the new seal causing a small hole and oil leak. Had to redo it. Was able to remove the timing cover by the lifting the engine with a floor jack and block of wood. Put a small piece of 2x4 under the engine mounts. This project took about 16 hours. Also, a new valve cover appears to have cured the oil leak. Car back on road and running ok.

Kevin, I have a 97 C280 with no oil pressure sensor and remember being told in a post, that at least on my car, if I can remember, that there is some sort of protection in the engine that shuts it off automatically if oil pressure is lost, can anyone verify this?

Kenny- glad to hear of the good work.

I still wish I had an oil pressure gauge...