Hey all,

My 240D has "only" 315k miles on it and over the past couple days during cold starts it takes about 5 seconds to build oil pressure from cold (Mind you it's a cold start in Hawaii) and makes a racket of a noise until it gets pressure. Oil is relatively new (changed within the past 500 miles) and topped up religiously as it has been an oil burner in my ownership. Other than the cold start issues it ran and drove fine with no changes to the oil pressure gauge. Is there a possibility that the oil pump is tired/clogged? Or is my OM616 prematurely on its way out?

__________________
____________________________________________

1983 Mercedes 240D (290k)
1983 Audi 4000S (93k)
1977 Porsche 924 (38k)

What kind of noise? Bearings, cam, chain?

Could be a few things. I’d drop the oil pan and take a look at the pick-up/screen.

There’s also a check valve in the filter housing. If that’s leaking, your entire system has to re-prime on startup. Great post on the topic:

https://www.peachparts.com/shopforum/3076376-post45.html

Sounds like lifter noise

__________________
____________________________________________

1983 Mercedes 240D (290k)
1983 Audi 4000S (93k)
1977 Porsche 924 (38k)

The pressure relief valve in the oil pump may have stuck open. This is a likely culprit particularly if it happened soon after an oil and filter change. I'd suggest dropping the lower oil pan and replacing and or inspecting the oil pump and the check valve.

Driving with the low oil pressure isn't good especially since it is making odd noises, this indicates that the top end probably isn't getting all the oil it should.

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer

THE OP said...

"Other than the cold start issues it ran and
drove fine with no changes to the oil pressure gauge."

There is a change to the oil pressure, it takes longer to rise it's just that the change is only noticed cold. Also the engine makes a new noise which is often a sign of inadequate oil pressure.

The oil pressure gauge reads to 3 bar or approximately 45 psi, all that is known at that point is that 45 psi has been reached. The pump has the ability to produce more than 45 psi but we don't know how much more it is producing due to the limitation of the gauge. If the pressure relief valve is hung open slightly which isn't that rare following an oil and filter change the designed maximum oil pressure will not be achieved.

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer

Do you change the oil yourself or does a shop do it?

I've been doing it myself for 6 years now

__________________
____________________________________________

1983 Mercedes 240D (290k)
1983 Audi 4000S (93k)
1977 Porsche 924 (38k)

Just checking, shops have been known to put
in the wrong oil among other things.

You may already be doing this...

When changing the oil and filter on OM616 and 617 engines check that the passageway inside the long tube on the oil filter housing lid is clear. Mine got restricted by a small piece of cellophane like material, after that I got in the habit of flushing it with brake cleaner and yes that is messy. Don't forget to renew the two small o-rings on the bottom of that same tube as they get brittle.

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer