So about 4 or 5 months ago I started hearing what sounded like an exhaust leak coming from around the passenger firewall / footwell primarily when accelerating under load in a high gear after the engine is warmed up...

Gradually it got worse until I had had enough and started researching. I quickly found a trend of broken exhaust manifold bolts here on the forum. So I took a look and sure enough the back most stud was broken off flush with the head.

After easy out-ing the broken bolt and replacing all others with new bolts and lock washers, and also replacing the gasket I was sure the problem would be fixed.

Nope. So I took another look and found a hairline crack in the manifold...replaced the manifold and noise is still exactly the same.

The only other possibility I can think of is a leak at the manifold outlet / flange.

Has anyone else ever had it leak there? I'm almost 100% sure it's an exhaust leak and just as certain it is passenger side...just running out of ideas and optimism.

 

I suspect the problem might have been in using lock washers. When I did my headers, I was going to use the locking bolts available but was cautioned against using them by a friend who used to run a performance shop.

His reasoning - in an aluminum engine if the bolts cannot give then the weakest point is going to go. He had seen multiple times where the threads stripped out the block with locking bolts. So I gave in to just having to check and re-torque my bolts around every other oil change or so.

I'm thinking same principle here except the manifold went instead of the threads...

 

Sorry should've noted...I did it without washers the first two times I took it apart and put back together with the old gasket and with the new gasket.

I then added the lock washers on the 3rd go round.

 

ANY time working with an exhaust manifold, let the engine warm up to operating temperature. Shut it off, let it cool, then re-torque the bolts. Also, make sure the doughnut ring is in at the end of the manifold. Those can deteriorate and start leaking too. They are reuseable if in good condition.

 

donut ring...please explain. If there is or was one I didn't see it.

I still have the old manifold out on my bench...don't see a donut ring or gasket of any sort there at the end of the manifold nor was there one on the replacement.

 

I guess it's not on the stock, but I found this gasket.

http://www.autozone.com/autozone/par...820725_0_7472_