Muffler Pipe Cracked

[rayman1946]

Why is my muffler pipe cracking around where it bolts up near to flange at turbo? It was cracked with only 1000 miles on it. I removed muffler and Tig welded cracks, now it is cracked again right next to where I welded it. Is there some reason for this, or a known fix? (Its on a 2005 smart 450)

[babybenz]

turbos are known to crack manifolds

[Leroy]

It is a problem with some G&K cars. There is a small cat that was added to the muffler which weakens it. Replace the muffler with an aftermarket muffler and you will not have any problems.

Leroy

[sunnyokanagan]

The weight of the 450's muffler with built-in catalytic converter makes the rigid downpipe susceptible to breakage due to the fact that the engine, which vibrates, is connected to the muffler, which is rigidly mounted to the transmission case, which doesn't.

Here's one simple mitigation... use spring-loaded manifold bolts and file a radius shoulder on the inside of the mounting flange where it presses against the down-pipe trumpet.

[rayman1946]

I think that might be the solution. Great Idea. I will do that when I take muffler off to weld it again. Thankyou very much. I'll let you know how it works in time.

[ASmartMan]

rayman1946

You may also want to contact G&K, they may be able to help as well.

Just a thought

ASM

[idahosmart]

Some of the G&K conversions have had this crack. Mine so far has not cracked, but I did get a letter from them over a year ago stating that they would pay for the repair if needed.

Tom

[briansmart]

Originally Posted by sunnyokanagan

The weight of the 450's muffler with built-in catalytic converter makes the rigid downpipe susceptible to breakage due to the fact that the engine, which vibrates, is connected to the muffler, which is rigidly mounted to the transmission case, which doesn't.

Here's one simple mitigation... use spring-loaded manifold bolts and file a radius shoulder on the inside of the mounting flange where it presses against the down-pipe trumpet.

Brilliant fix!! I will do this once I replace the spark plugs in my car.

[hoov23]

Contact G&K, they were sending out new mufflers to people whose mufflers cracked because of the old cat. I don't know for sure if it's still covered, though, but it used to be.