Guys, I had someone replace my exhaust pipes & muffler as the old originals had finally gave out. But now I have an exhaust leak in the engine compartment. I took a look and it appears everything is connected properly.

However...

Right at the top of the front exhaust pipe... Pretty much where it bends downward and heads through the engine compartment, there is a round circle in the pipe about the size of a quarter or half dollar. Some kind of vent hole or whatnot. That is where the exhaust is exiting. This isn't a part that was replaced. New replacement pipe is connected to this section.

What is this hole for and why is there exhaust spewing out? I can bring it back to the guy who did the work and make him deal with it, but I almost suspect this is an easy fix...

AFAIK, there shouldn't be any hole as you describe.

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83 SD

84 CD

I'll post a picture. It's definitely there and appears to be original to the car.

Possibly where the pipe for the EGR (Exhaust Gas Recirculation) valve was attached to the exhaust manifold. If it was removed there would be a hole there.

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Western NC
1987 300SDL W126 Turbo Diesel 335,000 + miles
1976 300D W115 275,000 miles+

Here you go. I'm calling it a "hole" but really it's that circular piece at 12 o'clock. What the heck is it for? How would I stop exhaust from pouring out?

Just like Jputt said, EGR.

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'82 300SD - Somewhere over 220k - Becoming reliable...

http://www.monstercraftsman.net/ makes a blocking kit. Very nicely done, I have one I need to install still. John is a great guy and will set you up with what you need if you shoot him an email.

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1985 300D (CA, 173K)

Dynamite Biodiesel Co-op, Phoenix,AZ

How's the project going? I've not seen too much activity on picasa - busy with other things?

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Agreed.

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83 SD

84 CD

Sounds good guys thanks for the advice. I'll go ahead and install it.

Quick question to finish this thread off...

His website says "The EGR valve let's exhaust gas be re- burnt through the intake of the mercedes turbo diesel engine"

I have the non turbo model, but I'm assuming this valve is the same on both turbo and non turbo?

You have an egr valve of some sort, yes it does the same thing.

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83 SD

84 CD

Thanks guys. I talked to Jon as recommended. The right thing will be to remove the EGR since it was added to regulate emissions after the fact and wasn't originally designed to be part of this system. Sounds like the engine will benefit from having this removed. And since they don't inspect for emissions in my state anyway... And the kit costs $30... Problem now solved. Thanks again.

So I did install the kit to block the EGR valve holes, and that has obviously fixed the problem. Much much quieter now, and I do believe I have a tad more power. Feels like a smoother shift as well but that's probably just in my head since now it's all been muffled. Or maybe there was a vaccuum leak caused by the egr not being connected properly.

Believe it or not... When I had my muffler replaced, the guy who installed it literally broke off my EGR valve, at the flex pipe. It was laying in the engine compartment wedged underneath some other parts. Which is why I couldn't understand what this hole was for... There was literally a part missing. Moron.