I just bought new exhaust, front to back

ANONYMOUS

MEMBER
2000 GMC JIMMY
115,000 MILES

I just bought new exhaust, front to back. A new catalytic converter with all the pipes attached, and a Dynomax exhaust system. I want to protect it. The cat and pipes are stainless but I worry about rusting at the welds, the exhaust is aluminized steel. I live in an area where corrosion is a major issue, is there any reason why I shouldnt paint everything including the cat and muffler with high heat exhaust paint?

4 Replies

CARADIODOC

MECHANIC
33,743 POSTS

I've gone through the same thing but it's hopeless. The pipes rust out from the inside from the moisture that condenses in there. The best way to make the pipes last is long enough trips on the highway to get those pipes nice and hot.

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Sunday, March 17th, 2013 AT 6:12 AM

JOEBOLDT

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1 POST

That's good to know! Would the paint hurt or affect the cat or muffler negatively?

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Sunday, March 17th, 2013 AT 6:30 AM

MHPAUTOS

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31,938 POSTS

In the good old days, mufflers had a small drain hole at the back of each muffler, I still run a 1/8 drill through to help drain off water after short trips, been doing it for 45 years, but the steel used to day is just so thin its just rubbish.

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Sunday, March 17th, 2013 AT 10:35 AM

CARADIODOC

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33,743 POSTS

You don't want to get paint or rustproofing on an oxygen sensor. They measure the oxygen in the exhaust system by comparing it to the oxygen in the atmosphere. You don't want to block that tiny opening between the wires. Also be aware oxygen sensors don't work until they get to 600 degrees. Any paint on the catalytic converter is just going to burn off. You'll need engine paint to withstand the high temperatures the pipes will get up to.

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Monday, March 18th, 2013 AT 12:16 AM