Oil Pressure Question
 

I posted this question on the Diesel list, but since its also applicable as a general question, I thought I'll post it here as well.

Lately I noticed that when I start my 95 E300D in the morning, It takes awhile (4-6 Seconds) for the oil gauge to peg at three. During this period you can hear the valve lifters clutter. So I know its starving for oil. I also noticed that when measured cold, my oil level has RISEN slightly from what it was several thousand miles ago. After this initial lag in oil pressure build-up, the oil pressure is fine If I start the car after 2-3 hours of having been parked, its also fine. Its only after extended periods, (more than a few hours) that this occurs. I am using Mobil 1 15W50 Synthetic

At first I thought its the oil filter, so I changed the filter, (Original Mercedes) as well as the two "O" rings on the oil filter shaft. No difference. Its acting identically as to what you would observe after an oil and filter change when it takes awhile for the pressure to build up again.

I am certain that the oil is draining out of the oil filter back into the crankcase. I suspect that this is the reason that my oil level has also risen slightly. Given that I replaced the filter (Mercedes Filter) and the 2 rubber "O" rings on the oil filter shaft? any ideas as to what would cause the oil to drain out of the oil filter housing back to the crankcase?

Thanks

Phil

Are you sure you are parking the car in the same spot every time you check the oil? My '94 wagon oil level on the dip stick changes with even a very slight incline or decline. Don't know about the pressure lag though? How long have you owned the car?

I always measure my oil level in my garage. I am certain that the slight increase in oil level is due to the oil draining out of the oil filter and back into the crankcase. I am just trying to figure out what will cause that.

I owned the car for about 3 years now. It came with a rebuild engine by Mercedes. Not sure what happened to the engine prior to me buying it from the Mercedes Dealer. The "New" engine now has approximately 30,000 Miles on it.


Phil

I think it's relatively normal
 

My '95 diesel takes a few seconds to peg also. And I hear the valves until the gauge comes up. Personally I wouldn't worry about it. My car just rolled over 190K miles.

Unless your oil level reading was under very controlled conditions I am suspect as to whether the oil level has actually risen.

I know that when I change the oil, at first start it takes much longer for the gauge to peg, which I've always presumed was the oil filter can filling up.

So bottom line, IMHO just grin and bear it - I think it's normal.

Rgds,
Chris W.

Just dug this thread up because my 91 300E with just under 150K is doing the same thing. Ticks for about 5 to 10 seconds at startup, with no oil gauge reading, then eventually ticking goes away and gauge is pegged at 3. If the car sits a couple hours, it's OK, but any extended sitting and the ticking will occur again (like overnight).

Are you guys sure this is normal?

Oil Pressure Problem
 

If the car has a canister oil filter, sounds like the check valve is bad in the filter housing. I would definitely look into it and have it attended to. Just a thought.

My gauge goes all the way up within 1-2 seconds of it being started. When it reaches optimum temp, then it falls a little.
You may want to check or replace your oil pressure sender.

oil pressure
 

Additionally, if there is a check valve upstream of the oil pump and filter, it could be leaking back causing a delay in oil supply to the valvetrain. I doubt it is normal, even if common, for the valvetrain to be noisy for even a few seconds. Just my opinion, I don't know this engine. Do you know if all oil from oil pump runs through filter first, or just a fraction?