During recent head replacement, i had the manifolds off. The intake manifold was loaded with major black gunk!!! ...at least 1/4 inch thick all around. Very messy job to clean (solvents, engine cleaner, big bottle brush, etc.)

What causes this..blowby past valve guides??


Thanks,

Mark

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1984 300TD Wagon, 407,800 mi (current daily driver)
1985 300DT Sedan, 330,000 mi (gone to that great autobahn in the sky)

Matt this is caused by normal oil vapors that are blown by and enter the combustion chamber. The EGR then sends very hot soot laden exhaust gases in there at the same time and "cooks" the oil vapors into that gooey paste. I disabled/blocked off my EGR and no longer have that problem.

CJ,
How do you disable/block off the EGR?
Thanks



David

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1985 300D Turbo

For the pre-85 cars you can simply put a BB in the vacuum line to diable it. For 86 and later/computer controled cars you can simply make a block off plate to block the EGR from putting crap into the intake.

CJ,

Why won't putting a restriction in '86 and newer Diesels stop the EGR from working?

P E H

You can use the BB trick on the 86/87 OM603.96x (3.0L), and probably all diesel models up through 1989. This works fine IF the spring inside the valve is keeping it closed, and the valve itself is sealing. Otherwise you can still get some exhaust leaking into the intake. The more permanent fix is to install a blocking plate of sheet metal between two gaskets. Or, as I plan to do, make a flat plate of 1/4-inch steel and remove the valve entirely! I just need to figure out how to plug the hole in the exhaust manifold.


From 1990-up the computer (EDS - electronic diesel system) controls more than the older models. This applies only the OM603.97x (3.5L) and OM602 (2.5L) engines, which were the only two sold by Mercedes between 90-94 (the 95 E300 got the new OM606). Although I don't have personal experience with one of these (don't own one) I have heard from numerous sources that if you disable the EGR (through a BB or other means), it confuses the computer (it has more sensors that the older models) and makes the car run worse, not better. If I ever get my hands on one I'll experiment, there HAS to be a way to disable it somehow!


HTH,

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Dave
Boise, ID
Check out my website photos, documents, and movies!

I disabled the EGR by the method of a bloeck off plate. This allows the EGR to still open and close. I am not aware of any other sensors in the exhaust or EGR that would know that there is a plate in there. My car does not throw any trouble codes and it runs great.

GSXR
Here is my answer. Took 1/4 inch plate steel made block off, used a gasket and original bolts to remove Egr, Then went to hardware store and purchased a 1/2 and 3/4 pipe end plug. Taped threads into manifold and JB Welded and run plug into manifold and used clam shell clamp over plug that was there orignally. On leak and no EGR.The reason I purchase both size I don't remember the corect size. You only use one. I thinks it 1/2. Good luck. Charlie