My 617 head seems to be leaking oil any quick fix? - PeachParts Mercedes-Benz Forum

777funk · #1 07-27-2007, 10:49 AM

I have good compression (around 400 psi) on my 617 but it is burning oil everytime I hit the accelerator.

I think this means my head has some leaky valves. Is there anything I can do?

One guy said have it machined but that's too expensive for this car (ugly smelly 300sd 116 body with 300k). Is there an easy way (or something I can do myself) to fix it?

I unplugged the blowby hose to see if it was sucking oil in the turbo. Not it either. So must be the valves.

What can be done?

#2 07-27-2007, 12:02 PM

You can replace the valve stem seals. After 300k miles they will be hard and brittle.
HERE is the document that tells you how to do it. Contact forum member wHunter and he should be able to get you a kit.

vstech · #3 07-27-2007, 12:08 PM

it could also be the turbo bearing seals too... that would put quite a shot of oil into the intake charge as well...

777funk · #4 07-27-2007, 12:49 PM

Well thanks you guys, vs how do I know the turbo is leaking?

Jeremy5848 · #5 07-27-2007, 01:04 PM

Quote:

Originally Posted by ForcedInduction

You can replace the valve stem seals. After 300k miles they will be hard and brittle....

That looks like something a journeyman DIY mechanic could do. Is there a similar procedure for the 603 engine?

Hatterasguy · #6 07-27-2007, 01:10 PM

It sounds like turbo seals, check out the turbo, see if its wet.

If its valve steam seals usualy you will see some blue smoke on start up then it will go away.

The crankcase vent has nothing to do with the turbo, the turbo is lubed via a high pressure oil line.

777funk · #7 07-27-2007, 01:33 PM

On the 116 chassis 617 turbo the CCV goes directly to the bottom of the U tube right to the turbo so it would spit any oil right there.

Quote:

Originally Posted by Hatterasguy

It sounds like turbo seals, check out the turbo, see if its wet.

If its valve steam seals usualy you will see some blue smoke on start up then it will go away.

The crankcase vent has nothing to do with the turbo, the turbo is lubed via a high pressure oil line.

Hatterasguy · #8 07-27-2007, 01:47 PM

I'm talking about failed turbo seals, the turbo is lubed via a hard high pressure oil line. The shaft spins at like a million RPM and the seals wear out, causing high oil consumption.

CCV system has nothing to do with this.

777funk · #9 07-27-2007, 01:59 PM

Oh yeah,
I know what you're saying.

That's something I've wondered as well. There's not much play in the turbo shaft. I don't know if that's the way to tell.

I had this in my original post:
'I unplugged the blowby hose to see if it was sucking oil in the turbo. Not it either. So must be the valves.'

I think that's how we got onto the CCV discussion. Anyways, that was just another diagnostic of my own. I put that to rule it out in the thread. I realize these are two different topics on how oil gets into the turbo and intake. But I was explaining my thought on the blowby possibility. The CCV setup is a little different on this 617 (in the 1980 300SD Turbo) than it is in the familiar 82-85 300d 617 engine. I've had both. This CCV goes right to U tube and the turbo. On the 300d it goes to the air box.

Just to clarify, I know we're talking about two different issues on the oil in the intake. The blowby was something I put in my very first post on the thread as something I ruled out.

Thanks,

Nick

Hatterasguy · #10 07-27-2007, 04:19 PM

I figured we were talking about two different things.

Is the intake really soaked with oil? A little is normal.

777funk · #11 07-27-2007, 10:40 PM

No I pulled the u-boot off and it looks a little greasy but not soaked by any means. I can't get my finger in the turbo to see if there's a pool in there, but I don't think there is. That's where I thought it'd be the valves leaking. Someone else on the forum led me to believe this a while back.

But... my guess is that the oil only would leak from the turbo oil feed when the turbo is spinning. It has a layer of oil as a bearing. But of course when sitting no oil is flowing so no mess. But when it is spinning, it'd easily suck all the oil it has spit out right into the intake. Especially at high revs since the turbo is flying at that point. So... it could be the turbo leaking.

How do I diagnose? Do I need to take the turbo off and run it without it? Is there an easier way to tell if that's the prob?

Quote:

Originally Posted by Hatterasguy

Is the intake really soaked with oil? A little is normal.

Hatterasguy · #12 07-27-2007, 11:50 PM

Ask Brian he as more experiance with blown turbo's. From my understanding they get worse really fast and the oil consumption shoots up quickly. Has the problem gotten worse?

777funk · #13 07-28-2007, 12:22 PM

I just bought the car a few months ago. It seems to be burning a good amount when I floor it. It really goes pretty good. Seems to have a lot of power but when I look out the back in the rear view mirror, I'm very glad we live in the country. Of course it needs lots of minor fixes like new shocks etc. But I figured I'd get the engine running well before I fix anything else. I'd be anxious to hear from Brian or anyone else with turbo experience on how to tell if things are ok in that dept.

kerry · #14 07-28-2007, 03:25 PM

Quote:

Originally Posted by 777funk

No I pulled the u-boot off and it looks a little greasy but not soaked by any means.

I think you're looking at the wrong side. The oil would be going in with the compressed air and not showing up on the suction side. You need to look in the intake manifold.

777funk · #15 07-28-2007, 03:35 PM

Ok... so does that require taking off the Turbo? If so, I could just run it without the turbo attached and that'd tell me right away if it's the turbo spitting oil into the intake. But I'd guess this is a 3-4 hour job. Is my guess on par?

Is there a quicker test?