I have a 1991 hatch back it has a bad exhaust resonating vibration. It is especially bad on decelerating to a stop. The exhaust is in new cond. and the drive shaft is ok. Does anyone have any other ideas? It is getting worse and almost to the point I can not stand to drive the car because it hurts your ears so much.

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Re. 1

First check to make sure that no part of the exhaust system is touching any body part or real close like an 1/8" or closer. The only other possibility is a loose baffle inside the muffler or the resonator which is before the muffler.


Re. 2

I have been trying to get a quiet exhaust system for a year. The problems I have found to date are:

1) The heat shield on the exhaust manifold vibrates at about 3000 RPM. I tighted the bolts and it has improved.

2) The baffles in the resonator broke and a loud rattling sound would occur. Replaced it and the replacement failed six months later.

3) The mounting tabs that hold the heat shield onto the header pipe broke (rusted) and the shield buzzes. I have not fixed this one yet. I'm not sure about
removing the shield.

Any of these areas could cause your problems.

Re. 3

We had a problem on our car, after we had our muffler looked at. They had tightened the hang, and it ended up bumping the shipping hook. Had a muffler shop melt that puppy off, and it was fine.

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Re. 4

Hi there, I had the same problem too and I found out it was the heat shield.
I am pretty sure that is what is causing all the noise. Its not that costly
a procedure and if your worried that you need the heat shield for some
reason you really don't, its pretty much pointless and yes very annoying.

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Re. 4

I tracked the annoying vibration that occurs around 3000 rpm's to the heatshield that covers the end of the downpipe right before the "real" Cat. and not the main heatshield in the engine bay. I went to remove this sucker and some of the bolts were so rusty that they broke right off as described earlier. There's a total of 6-8 bolts to remove plus a round retainment bracket at the end. There are two pieces to remove, and the top shield takes some twisting to pull out. Once off all the "bad vibes" were gone. It took some time to pinpoint the source since it's located underneath you while driving!

Steve D.F.
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What is that darn rattling sound that all 240's make? 89-90 and maybe others.

The darn heat shields are to protect someones lawn from getting burnt or torched if you park over dead grass. This is because the 240 is a low car. I would just remove them all and don't park on a dead lawn or over a pool of gas. Everything will quiet up after that. Unless you have holes or loose hangers. but 9 times out of 10 it is the heat shields.A muffler shop should do it for under $40. Good luck

Brett Sandstrom
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