Exhaust manifold cracking

HALLEY

MEMBER
TOYOTA COROLLA

Hello, I own a 1996 toyota corolla ce 1.6 litre engine with 157,000 miles. I have had four exhaust manifolds replaced on this car and it continues to crack all the manifolds in the same spot on the manifolds. All replaced manifolds were new aftermarket, made of heavier castings to be able to withstand cracking. Each time new gaskets were installed and all bolts were torqued to specs. What could be causing this re-curring problem? Thanks for your suggestions.

Sunday, November 25th, 2007 AT 10:52 PM

1 Reply

MMPRINCE4000

MECHANIC
8,548 POSTS

It could be an issue with air/fuel ratio (running lean), or the replacement manifolds could be inferior to the Toyota manifold.

I would ask Toyota if there was an issue with this particular year regarding cracked manifolds.
I would have the PCM scanned to see if there is an indication of a lean engine (PCM trying to add fuel).

In 1991 Toyota had a problem with cracked manifolds caused by the heat shield (the factory shield had no vents). They replaced the shield with one that had several vents (slits in the steel) that helped cool the manifold and it solved the problem.

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Monday, November 26th, 2007 AT 6:09 AM