OM603 dripping oil at front of engine and terribly noisy. - PeachParts Mercedes-Benz Forum

ah-kay · #1 04-17-2016, 08:16 PM

Need some help and pointers as to what was wrong with my 300SDL. Ran an errand to pick up some Mercedes parts from a CL seller. Engine was noisy than usual but I did not pay much attention. Doing 70-80mph on freeway with radio on, car ran fine. At the seller place he told me the engine was very noisy even for a diesel. It was in fact terribly noisy when I listened to it. We noticed engine oil dripping continuously on the driveway when idling. We could not figure out why but I suspect it was the front crank seal. Engine oil was at the full mark so I drove home, no problem. Engine was noisy but drove fine at 70mph. It is now in the garage and this is the symptoms I noticed.

1) Dripping oil all the way on the way back, oil spots on driveway leading to garage.
2) Oil pressure was good on the freeway. However, oil pressure is very LOW at idle, normally it is at 1 bar. Now it is below 1, nearly 0. Oil pressure goes up to 3 bar when I rev the engine, just like it should.
3) I have removed the clutch fan, serpentine belt and the belt tensioner to give me a better view of what is going on. There seem to be a lot FREE PLAY on the crank. Should there be any free play, front and back, up and down? Never try it before so don't know.
4) Should I drop the oil pan and take a look inside?

Any info is appreciated.

Mxfrank · #2 04-17-2016, 08:57 PM

Not sure what you mean by free play, but the crank should rotate without much resistance. You should never rotate the engine counterclockwise.

Removing the oil pan is a major PITA. You'll need ramps or a lift and an engine hoist. You really need to clean the engine off and see where the leak is coming from before you start wrenching. One of the problems you're dealing with is that the fan throws leaked oil all over the place, so it's hard to see where it's coming from. As for noise, one thing you do want to check is free play in the belt tensioner. It should rock up and down, but never ever front to back.

ah-kay · #3 04-17-2016, 09:07 PM

Quote:

Originally Posted by Mxfrank

Not sure what you mean by free play, but the crank should rotate without much resistance. You should never rotate the engine counterclockwise.

I do not mean turning the crank. I meant the crank has some 'free play' moving back and forth. Is it normal? I seem to be able to move it 'up and down', not 100% sure. I have removed the oil pan before so that is not an issue. I want to have a better understanding of the leak and the sound before I remove it.

babymog · #4 04-17-2016, 09:16 PM

I would have guessed a broken timing-chain cover at the tensioner, but since you have removed the tensioner, you probably would notice.

No other guesses!

86-300sdl · #5 04-17-2016, 10:00 PM

I don't have any observable vertical or forward /aft play in my sdl motor if that means anything.

But noise + crank play+ low oil pressure at low rpm begins to sound like bottom end problems.

But maybe the timing chain tensioner is failing or backing out with resulting oil seal leak and a less than tight timing chain

I had a timing chain tensioner seal split and it spit oil only at mid to higher rpms in a fine mist that was then blown around the front end, collected and began to drip. Looked like the oil was leaking from the timing chain cover at both the belt tensioner and the crank.

P.S. Is this the motor that had the oil pump chain snap?

ah-kay · #6 04-17-2016, 11:59 PM

Quote:

Originally Posted by 86-300sdl

I don't have any observable vertical or forward /aft play in my sdl motor if that means anything.

But noise + crank play+ low oil pressure at low rpm begins to sound like bottom end problems.

P.S. Is this the motor that had the oil pump chain snap?

Yes. This is the motor with the oil pump chain snapped. It had done 20k since the repair so the warranty is out, my own warranty. I think you are right it may be the bottom end. It is a loud knocking noise. I may remove the oil pan and take a look.

Maxbumpo · #7 04-18-2016, 09:17 AM

Sounds to me like the nut holding the crankshaft balancer to the crankshaft has worked loose. Hopefully the damage is not too significant! Hub on the end of the crankshaft and/or the balancer may be toast.

86-300sdl · #8 04-18-2016, 04:59 PM

Mr. Ah-kay

Let me know if and when you could use an extra hand. I know you're well accomplished. But in return for all of your assistance I'd like to offer up a little "return favor".

P.S. Seems like your "warranty" is unconditionally unlimited

Quote:

Originally Posted by ah-kay

Yes. This is the motor with the oil pump chain snapped. It had done 20k since the repair so the warranty is out, my own warranty. I think you are right it may be the bottom end. It is a loud knocking noise. I may remove the oil pan and take a look.

awsrock · #9 04-18-2016, 10:00 PM

I second crank pulley bolt got loose and or fell out.

ah-kay · #10 04-29-2016, 06:20 PM

No wonder there is so much free play in the crank pulley. I can move the crank pulley, up and down, front and back. The crank was snapped at front of piston 1. Bad bad news. Surprisingly, the car still run! What are my options with the least work? The car is rust free and in very good condition.

1) Junk the car and harvest the good parts, radiator and other light items.
2) Change the lower block.
3) Change the engine.
4) Change the crank.

I am leaning on option (1). Anyone suggest otherwise and why. Out of option 2-4, which one is the least work. Can you weld a crank? It seems to be doable from underneath the car, the break is very clean. Any input is appreciated.

jt20 · #11 04-29-2016, 07:10 PM

considering your approach on other topics, the most direct solution would be to change out the entire bottom end.

the machine work is quite do-able and could be fixed otherwise. if you drive it much more, that will not be the case.

jt20 · #12 04-29-2016, 07:11 PM

what do you think caused this?

was there damage to the crank when you opened it up for the oil sump before?

ah-kay · #13 04-29-2016, 07:21 PM

What I meant it ran is I drove 20 miles home with the broken crank. I have not driven it since. I do not know what happened and why the crank snapped now. The engine seized when the oil chain snapped 20K miles ago. The crank may have been weaken then, I do not know. I 'fixed' it and it ran fine for 20K until lately ... I did not measure the crank, it is possible that the journals were out of spec.

So what next?

jt20 · #14 04-29-2016, 07:40 PM

the engine seizing on a broken chain in the front pretty much sums it up for me, at least.

the crank was weakened then; some microfractures, or perhaps a large one that held for a while, were born.

if you opt for just a replacement crank, you'll need a balanced assembly: flywheel, crank and the front balancer (if it has balancing bores on it, I forget - the 601 doesn't). Unless you can prove that your flywheel is neutral and the replacement crank is as well.

then it would be in your best interest to have a machinist check the rod and piston for distortion on that cylinder.

...but, you could probably drive it for a long time just be swapping the rotating assembly out.

installing the new crank means checking each bearing for clearance spec : plastiguage

sounds you'll at least have one bad bearing on a rod - it might not look like it, but i wouldnt use it.

dieselbenz1 · #15 04-30-2016, 12:03 AM

My vote is 3) since the engine has to come out anyway provided you can source one at a fair price.