1. Home
  2. Mercedes Autos and SUVs
  3. Turbo Diesel oil in intake manifold?

Turbo Diesel oil in intake manifold?

I was changing the glow plug harness in my 1994 S350 (168k) and took off the intake manifold to get at things. I think I found where the blue exhaust smoke is coming from. The manifold is caked with thick oil residue that looks like it has been there for years, but also has a thinner layer on top that looks rather recent. I can trace it right back to the turbo. My guess is that there has always been a little bit of oil coming from the thing, but now there is a lot. Looks like I'm down about a quart in 1500 miles. Haven't noticed any oil loss before the last oil change

- at least not much (always leaks a bit here and there).

Are there any seals or gaskets or whatever in the turbo that can be replaced?

What to do?

Thanks

-Dave Walton

Reply to
Dave
Loading thread data ...

The intake manifold will be caked with soot and oil. Soot from the EGR system - normal - and a bit of oil from the crankcase ventilation system aka as "the breather" - also normal.

I believe there's a vent hose from the top of the valve cover over to the air cleaner or some point on the air passage to the turbo's air inlet. There's always a bit of oil in the crankcase fumes and it is what you see inside the intake manifold. Normal. Don't blame the turbo, they rarely fail.

Reply to
T.G. Lambach

Are you aware of this 3.5 L diesel's reputation for bending its connection rods?

Oil consumption - usually past the #1 and #4 pistons - is a symptom of greater things to come. Owners of these engines have not been a happy lot.

Reply to
T.G. Lambach

I have come across references to this engine problem here and there, but was unable to find anything that covered it in detail. Is this fixable?

Thanks

-Dave Walton

Reply to
Dave

Although M-B denies that any design defect exists, they did produce a heavier version connecting rod. However, I recall something about it having limited availability which doesn't make sense but that's what I read.

The problem is well known, especially to owners of the engine. I believe I may have some pictures of the connecting rods and will try to email them to you directly. I'm not an email expert so don't be surprised if nothing appears. Tom

Reply to
T.G. Lambach

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.