OM602 Turbo Leaking Oil - Need Help to ID Cause - PeachParts Mercedes-Benz Forum

300D-91 · #1 08-09-2015, 10:17 PM

The turbo on my 91 OM602 (318K miles) is leaking oil. Just finished a round trip to Hartford CT (~500 miles). After pulling into the garage I saw oil drops. Opening the hood you can clearly see where the outside of the turbo oil drain line is wet (including the frame and everything below). The top of the turbo at the oil feed line and the casting it's bolted to is also wet.

Checked the feed line and it's tight - what else could it be? Admittedly I'm not a turbo guru and expected it to start leaking into the exhaust or intake if the bearings are going bad. Didn't expect a wet engine compartment

Im leaving in 3 days for a trip to Montreal QC (~475 miles 1 way), now I'm concerned it could burn up or stop working on the trip.

Any ideas / suggestions how to troubleshoot this are appreciated. I'll post some photos tomorrow...

Phillytwotank · #2 08-09-2015, 10:33 PM

Start by cleaning everything. Getting it dryed up will definitely help to pinpoint exactly where it is leaking.

dieselbenz1 · #3 08-09-2015, 10:44 PM

Pull the air inlet to the turbo and see how wet it is inside the inlet could be a lot of blow by.

Mxfrank · #4 08-10-2015, 07:20 AM

There's a paper gasket under the oil feed fitting that may be the cause. The return line directly underneath has similar gaskets on the turbo and the block side. The return tube is jointed with a rubber o-ring between the two sections. Any of that can be leaking.

Oil in the intake isn't necessarily indicative of excessive blowby, but let's not go there yet.

300D-91 · #5 08-10-2015, 09:44 AM

Phillytwotank everything was clean before I left for Hartford, so I'm confident this is fresh. Still need to get under the car for a different view.

dieselbenz1 the valve cover doesn't vent into the air intake system (it's vented into the atmosphere).

Mxfrank later today I'll pop off the feed line and replace the gasket. Then look at the below gaskets and O-ring. Thanks for the information!

leathermang · #6 08-10-2015, 09:54 AM

Quote:

Originally Posted by Phillytwotank

Start by cleaning everything. Getting it dryed up will definitely help to pinpoint exactly where it is leaking.

X2 and I will expand on the concept.... once clean you do SHORT trips.. maybe just around the block...and check again... then a little longer..
You may not be able to drive all the way to Hartford and it be obvious where the source of the leak is...

300D-91 · #7 08-10-2015, 10:53 AM

leathermang Just finished wiping everything down, then I replaced the feed line gasket.

It could still be the lower (return line) gasket, but it doesn't appear to be the O'ring (leak starts much higher).

Right now I'm off to a new fuel leak, let's see what the new feed line gasket does ....

Thanks to everyone in this thread for the feedback, always appreciated.

300D-91 · #8 08-11-2015, 09:41 PM

[UPDATE] The gasket I removed was a black material (non-metal), using it as a template I made a replacement using standard oil resistant gasket material.

It leaked

So I made a 2nd - it also leaked

Put the 3rd homemade one in tonight with a little gasket sealer on it. Fingers crossed it doesn't leak too bad until I finish my trip to Montreal QC. I'm going to call the dealer tomorrow and order a new one so it's here when I get back.

Guess I'll make a few spares and toss them in the glove box just in case....

300D-91 · #9 08-17-2015, 09:41 AM

After a round trip to Montreal gasket #3 w/sealer leaked

Today I'm going to make a custom gasket from soft copper.

In the back of my mind there is this fear that there is a crack in the casting and no gasket will fix this.

Maxbumpo · #10 08-18-2015, 03:14 PM

Why not try an OE gasket from the dealer?

A casting doesn't just crack by itself. What could have caused the crack? Do you mean a casting in the oil feed line, or in the turbo housing?

300D-91 · #11 08-18-2015, 04:19 PM

Quote:

Originally Posted by Maxbumpo

Why not try an OE gasket from the dealer?

A casting doesn't just crack by itself. What could have caused the crack? Do you mean a casting in the oil feed line, or in the turbo housing?

After many cleanings I'm confident the leak is above the turbo housing. Not saying there is a crack in the oil feed line or the casting on the end of that line. Just considering possible causes....

Ordered 2 gaskets from my dealer yesterday, pick them up tomorrow.

BatteredBenz · #12 08-18-2015, 04:29 PM

I've had an oil feed line crack right where it enters the block that bolts to the turbo oil inlet. I think that was caused in part by the PO who had removed the single 10 mm bolt that secured the oil feed line to the turbo assembly on the OM603 this happened on.

after you've cleaned and put a new gasket in place have you tried to observe that area with the engine running?

300D-91 · #13 08-19-2015, 04:24 PM

Picked up the new gasket this AM, this PM I discovered it's too big. Dealer is supposed to have the correct one for me tomorrow AM. Very anxious to see what the new one looks like because todays gasket is a green fiber and cost ~$2.50 - tomorrows will cost ~$10.00

300D-91 · #14 09-07-2015, 04:35 PM

Wanted to wrap up this tread with info on the fix.

After installing the factory gasket the leak continued. A (lot) of investigation uncovered that the feed line was 'weeping'. Cleaned it good with brake cleaner, then mixed up some J&B Weld for the repair.

Maxbumpo · #15 09-09-2015, 01:51 PM

How much is a new feed line? Seems to me that if it ruptures, catastrophic oil loss could then destroy the engine.

I'm also curious what caused the feed line to fail, and how will you prevent that condition from causing another failure. Someone mentioned in the posts above that there is a 10mm nut/bolt support that may be missing?