I'm working on a 1987 300TDT with a 603 engine. Only when the engine's running is there a strong smell of post-combusted diesel fuel. It is somewhere in the area of the turbocharger. I am standing over the engine while it's idling and definitely can smell an odor. I tightened the obvious clamps, but still no improvement. I can't see any smoke rising from the engine compartment but it is definitely there. Any ideas on how to find this leak?? A mechanic told my sister a few weeks ago (mind you, he's not reputable) that there were "pinholes" in the exhaust manifold. I have been under the engine and have looked at all angles with an inspection mirror and cannot fine ANY evidence of any pinholes in the manifold. It's got to be something smaller/minor. I'm positive he was just trying to sell an expensive repair ($1,000+). Anyone have any ideas???

Would putting really soapy water all over it when its cold, then firing it up and looking for bubbles on the manifold/exhaust pipes work? I'd think that'd be a good way to locate the place where exhaust is escaping. Don't let it get hot with soap on it though, shut it back down and rinse it off first.

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I suppose that might work, we do that with air leaks out of tires so why not? I just tried shutting the lights off in the garage here and holding a light near the offending area and I could see a tiny plume of smoke coming up from that whole area. I still can't narrow it down though.

There are only a few places for leaks and I doubt pin-holes too, but areas more possible are likely to be the manifold gasket, or loose manifold to exhaust pipe connection (three bolts/nuts) and also the trap replacement pipe (wrapped in aluminum) has a flexible stainless pipe with collar clamps, each end, are the only 3 likely places for leaks.

I had an exhaust leak and didn't know it until I replaced the manifold gasket voluntarily! I'd bet it is the manifold gasket, or loose 13mm nut, or nuts, fastening the manifold. I'd try tightening first!

There is a stainless steel flex tube that connects the two pieces of the exhaust manifold together between cyls 2 & 3. There is also another, larger one on the turbocharger. In my case, both were cracked and spewing a fine plume of exhaust. One way to find it is to start it up cold then put your hand around the area. you will feel the exhaust when you are near the leak. They leak more when they are cold since expansion helps to close the gap. Each set consists of an outer flex tube slipped over an inner stainless tube, all held in place with stainless clamps. In order to change them you have to remove the exhaust manifold and the turbocharger, as well as the engine compartment encapsulation on the bottom and the right side. It took me most of a day to do it, I took my time and cleaned everything. It's a good time to remove the intake and clean all the gunk out of it. A baby bottle brush works pretty good with lots of solvent.

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Brian
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the egr actuator.

also, if its any consolation there is no danger in smelling it as there is virtually no carbon monoxide in diesel exh.... stinky though. i just like to think "that is the smell of money going into my pocket".

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Thanks for the ideas. I doubt it's a pinhole issue myself, more likely a bad clamp since there are so many of them in there. The puffs seem to be coming from the far left side of the engine. Possibly the clamps to the EGR, or even the clamps that attach the metallic-lookin pipe. I hope it's not the manifold gasket. Not something I'm looking forward to removing.

assuming looking from the front toward the pass comp. then i would suspect the flex link between the manifold and down pipe on the exhaust.
but if you can see puffs you should be able to see the source iw ould think.


tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

My money's on the head pipe (like t walgamuth said). First flex pipe after the turbo, connects turbo to the resonator pipe.

Mine was split in two. The hardest part of removal was getting the first "half" away from the turbo. I had to stick a 2x2 into it from below and wrench it around until it popped off (after taking out the bolts, that is).

Tom,
It's such a small (but noticeable leak) that you can barely see the puffs with the shop/garage lights off and a small shop light at the firewall. Really hard to tell where it's from. That whole area is full of clamps and flex pipes though. I'm going to start the engine soon and see if I can't feel where it's comiong from.

Upon closer inspection, I discovered that the small flex pipe (with a clamp on either end, about two-inches wide) in between the manifold of cylinders 1 & 2 and 3,4,5,6 not only has a small area of black soot on it, but I could just barely feel a few puffs of smoke coming from it. Thanks for all the help folks!
Pinholes in the manifold my a$$. That mechanic was looking for a massive profit. It's people like him (this scheister in Maryland) that make the whole auto repair business look bad.

A lot of times they suggest the worst so as to prepair you for a major expense and if they are honest, they will repair only what they have found, but not before dismantling stuff in pursuit. It's a guess until they have found it, and it could have involved manifold removal, so they cover their asses!