M603 Oil in Crossover Pipe - PeachParts Mercedes-Benz Forum

beaulieub · #1 09-17-2006, 08:26 PM

Just opened the Intake Manifold and Crossover Pipe to find a LOT of oil sludge in both. Also, wiping inside the block openings, walls are soaked in oil. This is a fairly new to me '90 350SDL w/ 194K miles. Since Ive had it Ive had erratic and heavy oil consumption from 1 qt every 400 miles to over 700 miles. Seems to be related to driving speed. How dry should this crossover be? I'm hoping this means a turbo problem and not a rod bending problem. Car drives great.
I've got a fuel delivery valve which is leaking sooo - Now that the o-rings and springs and copper seals have arrived in the mail I figured I would remove the manifold to get at the del. valves and thus look for oil in the manifold - BINGO!
I'm also going to do a compression test and get some baseline numbers on this engine. Can I do a comp. test with the intake manifold off? Also, the holes in the block for each cylinder - Is this the pre-chamber Im looking into or the head?

Ill be back at it tomorrow so Ill keep you posted. Id like to hear any comments you all may have.

Thanks Bert - NH

BOMC · #2 09-17-2006, 08:55 PM

on my 603 in my 300D my charge air/crossover pipe was gunky with sludge at its connection to the air pipe comming from the turbo (see pik#1). the rest of my intake manifold was kinda coky/powdery/sooty black.

the way i see it, the only "normal" ways for oil vapor getting into the charge air and intake (leading to gunk) are from the EGR that dumps into it and the breather from the valve cover that scavenges vapors.

sorry i cant contribute anything usefull to the other questions,

jshadows · #3 09-17-2006, 09:41 PM

That's a lot of oil consumption. Check out turbo outlet and air intake for oil as well. Mine was spitting out a bit before I rebuilt (though more like a qt every 2K miles and I drive fast)

Brian Carlton · #4 09-17-2006, 11:10 PM

The problem is one of two possibilities:

1) Worn turbo seals allowing far too much oil to reach the intake.

2) Worn rings allowing too much blowby and too much oil ends up in the intake.

The only way to confirm which of the two is the issue is to pull the breather hose and run it into a bucket. Drive it for a few hundred miles and check the bucket. Either the oil is there.........or it isn't.

guage · #5 09-17-2006, 11:16 PM

There is a reason why they call the 350SDL (603 motor) rod benders.

jshadows · #6 09-17-2006, 11:19 PM

Quote:

There is a reason why they call the 350SDL (603 motor) rod benders.

Wow, with the number of times the obvious not necessarily likely conclusion is restated, we're going to have to start checking snopes.com to see if it's really true or not.

guage · #7 09-17-2006, 11:27 PM

Quote:

Originally Posted by jshadows

Wow, with the number of times the obvious not necessarily likely conclusion is restated, we're going to have to start checking snopes.com to see if it's really true or not.

Go right ahead.
And while you are their search cracked heads too.

Jadavis · #8 09-18-2006, 08:51 AM

My 87 300D uses 1/2 quart per oil change. I change the oil every 5,000 miles. I do not top up in between. You are using a lot of oil.

-Jim

sixto · #9 09-18-2006, 03:17 PM

You can do a compression check with the intake manifold off. Heck, you can drive the car with the intake manifold off.

Ideally you do a compression check on a warm engine. You'll get good information doing it cold but it won't be... uhh... ideal.

Depending on your compression tested, you can use an injector fitting or a glow plug fitting. Either way the fitting goes into the prechamber. The prechambers are in the head. There shouldn't be any holes in the block that lead to the combustion chamber. Likewise there shouldn't be other holes in the head that lead to the combustion chambers other than the prechambers and valves ports.

Sixto
93 300SD

gsxr · #10 09-18-2006, 04:02 PM

A few comments:

1) The oil in the intake tract is not really desireable, but it is pretty normal. Most of the 603's that I've opened up are oily in the intake tract. It's probably from the PCV system more than the turbo seals. I actually found a document in the WIS that says no warranty work is to be done to correct this, because it's normal... but I was never able to find the document again so I could make a PDF of it! (Some day I'll figure out where they're hiding it, lol.)

2) I used less than one quart of Mobil-1 in 10,000 miles on my most recent oil change, with 270kmi on the clock. A quart in less than 700 miles is definitely excessive.

3) A cold compression test may show if one or two cylinders are far off the others, but a warm/hot test is much preferred. The absolute numbers will be useless though, if done cold.

4) With that oil consumption, and a 3.5L engine, I'd be pretty surprised if you *don't* have a bent rod or two.

Only way to know for sure is to yank the head and measure piston protrusion.

5) For the delivery valve seals, don't forget the torque sequence... 30Nm, release, 30Nm again, release, final torque 35Nm. (The procedure is in the TDM, not the FSM, for reasons that still escape me.)

Brian Carlton · #11 09-18-2006, 04:09 PM

Quote:

Originally Posted by gsxr

A few comments:

1) The oil in the intake tract is not really desireable, but it is pretty normal. Most of the 603's that I've opened up are oily in the intake tract. It's probably from the PCV system more than the turbo seals. I actually found a document in the WIS that says no warranty work is to be done to correct this, because it's normal... but I was never able to find the document again so I could make a PDF of it! (Some day I'll figure out where they're hiding it, lol.)

2) I used less than one quart of Mobil-1 in 10,000 miles on my most recent oil change, with 270kmi on the clock. A quart in less than 700 miles is definitely excessive.

3) A cold compression test may show if one or two cylinders are far off the others, but a warm/hot test is much preferred. The absolute numbers will be useless though, if done cold.

4) With that oil consumption, and a 3.5L engine, I'd be pretty surprised if you *don't* have a bent rod or two.

Only way to know for sure is to yank the head and measure piston protrusion.

5) For the delivery valve seals, don't forget the torque sequence... 30Nm, release, 30Nm again, release, final torque 35Nm. (The procedure is in the TDM, not the FSM, for reasons that still escape me.)

One quart of Mobil-1 in 10,000 miles is not going to allow the intake tract to be "soaked in oil" as the OP described. In fact, it's barely going to give a light coating, IMHO.

If the engine bent a rod, the oil would be bypassing the piston and it would not show up excessively in the intake.

Now, he "might" have the problem of excessive blowby/bad turbo seals in addition to a bent rod, but, I doubt it.

I've personally witnessed a 603 with bad turbo seals that would consume 1 quart of oil every 200 miles. The intake tract looked like someone sprayed it down with a garden hose. Large globules of oil on all surfaces.

gsxr · #12 09-18-2006, 04:17 PM

On my car, the intake tract is always damp with oil - it's not dry. But it's not dripping wet, either. It's hard to quantify that though. I hear of very few failed 603 turbochargers. I'd want to make sure that was the cause before plunking down $500+ for a rebuilt unit and 5+ hours to swap it out, just to end up with the same problem afterwards...

beaulieub · #13 09-18-2006, 05:15 PM

Here's a picture showing a little oil pooled at the intake to the turbo on the fresh air side. Is this normal? Would this little bit of oil signify that the turbo is blowing oil into the engine? I did try the axle(?) of the turbo for excessive play. It moved very slightly - Im guessing its not worn too much. Let me know what you all think.

Thanks Bert - NH

gsxr · #14 09-18-2006, 05:35 PM

I see the same thing on my car - but it's not from the turbo, it's from the PCV tube that leads into the intake snorkel. I bet you'll find the rubber intake snorkel has quite a bit of oil inside as well.

jshadows · #15 09-18-2006, 06:22 PM

AFAIK the seal on the compressor of the turbo should not leak any oil. If it's a Garrett T3 the the compressor gas seal is a pretty complicated little mechanism designed to keep the oil where it's meant to be : on the bearings.

Attached are a few photos..sorry about the clarity, not my best photography ever.

Anyway, before I rebuilt I had oil gunk built up on intake hose coming from air filter and around aluminum portion of turbo housing. It was not excessive enough to cause major consumption or smoking off of exhaust manifold but enough to make a mess around the turbo and cause gunk to build up in the crossover pipe. And, if you can spend the 5 hours taking it out (though it really shouldn't take that long as long as airbox and heat shield are removed), you've got enough skills to rebuild the compressor side of the turbo for about $30 in parts (bearing, retainer rings, and new carbon gas seal)

That said, oil as BC said could come from two places here, either blowing past the turbo seal, or blow-by which will send it through the breather into the air intake stream.