turbo oil leak... not the usual ones - PeachParts Mercedes-Benz Forum

JHZR2 · #1 02-17-2004, 04:32 PM

Hi,

I replaced the turbo drain seals this past august. It still leaked some, so I had a professional MB only shop do it last November. It still leaks all the time, and so I brought it back today to have them re-do it.
They cleaned it all up really well, and replaced the gasket. again.

I drove it about 70 miles, and now Im giving it an oil change. I am seeing the same thing... seepage.

The mechanic who fixed it had a thurough look at it, and told me that it might possibly be coming from above the oil drain, and is dribbling along and dripping from that spot. Looking around now with the leak there again, I believe he is right. Looks to me like it isnt the gasket at all, but rather just above it.

What would cause this? I always idle the car so to prevent coking on the bearings, etc. If the PO shut it off too soon after a highway run, etc., could that wreak havoc on the bearing seals (I think the leaks started after using synth oil), so I think the leaks were clogged a bit previously.

So what does that mean, that the turbo bearing seals are shot? What is just above the oil return tube that could leak? Is thebest bet to just get another turbo and put it on? I plan to keep the car for 100k more miles at least, but at the same time, dont want to spend a lot of money on a new turbo.

The turbo will easily make 10.5 psi of boost, BTW, and if I set the boost controller too aggressively, itll make over 15psi, so it seems that internally it is healthy.

Thanks for reading my long post. Any information or advice would be most appreciated. Thanks,

JMH

JHZR2 · #2 02-17-2004, 05:53 PM

An update... I poked around in therew while doing my oil change, and found that one of the bottom bolts, directly above the flange where the turbo drain is, was loose.

I tightened it (no idea why it is loose or why it loosened itself), and we shall see if (hopefully)itll be OK. Im so careful with the turbo in terms of cooling down, etc., that I cant imagine that its bad. Plus, it spins easily and generates plenty of boost...

We'll see...
Thanks,

JMH

psfred · #3 02-17-2004, 07:36 PM

Don't forget that there is an oil supply line to the turbo, too -- on top.

If that seal leaks, oil will run down to the bottom and off the drain tube.

There is probably nothing wrong with the turbo itself -- bad shaft seals results in excess oil consumption, either down the intake from the front, or more usually, out the exhaust, to the point that oil will drip off the tailpipe! Lots of blue smoke under load, too.

peter

JHZR2 · #4 02-17-2004, 08:47 PM

OK, thanks...

The top (pressure) line is totally fine, 100% sealed. I have checked it numerous times.

And none of those issues you listed.

Are there any other places for an outboard oil leak from the turbo besides the oil inlet, drain and intake/exhaust?

Thanks,

JMH

psfred · #5 02-18-2004, 12:27 PM

Only if the body is cracked.

Peter

JHZR2 · #6 02-18-2004, 01:11 PM

OK, good to know...

Have you ever heard of a garret turbocharger that had a crack in its body from normal road use?

im sure that would be a first...

Thanks,

JMH

psfred · #7 02-18-2004, 02:39 PM

It's possible the seal between the compressor housing and the bearing cartridge is leaking, too -- this will dribble oil down the front side of the cart and onto the drain hose.

Peter

leathermang · #8 02-18-2004, 03:32 PM

ok, when you and the machinic replaced it the first times.. did you put a new gasket at the top of the tube ? and two new orings plus the ' sectional seal' at the junction of the top of the oil pan ?

JHZR2 · #9 02-18-2004, 03:52 PM

Yes, the correct paper gasket at the flange where the top of the tube mates to the drain on the turbo, and the various rubber parts at the other spots. It doesnt leak at the middle seal or at the entry into the oil pan, BTW.

Thanks,

JMH

JHZR2 · #10 02-18-2004, 10:11 PM

I think Ive slowed down the leak... Tightening the lowest bolt facing forward on the turbo body just above the turbo body drain flange, seems to have helped. It was pretty loose before, and I got it finger tight. Signs of oil on the engine mount after a 15 mile and a 45 mile interstate trip were scarse.

I think its a good sign. I didnt want to tighten it too much, maybe Ill try and get it a little tighter sometime.

I know there is oil in the intake side of the turbo, by where the U-tube attaches. I dont think there is much oil in the U-tube, but I think it must just be oil vapor from the breather tube, since there is no sign of burning oil.

Hopefully the tighening will fix it. If not, since the turbo is still providing great boost and not burning oil, can I put some 'liquid gasket' type stuff in spots that the leak could potentially be from, and let it dry on the turbo body to help stop the leak? It would be a lousy repair, but would keep the engine clean and buy some time before I send the whole thing to be rebuilt and balanced.

Thanks,

JMH