Hey guys, I have a 91 caprice wagon with the tbi 305 (ya...its a roach). I purchased it from an older man who had backed into a curb and kinked the tailpipe at the end. I hacked this off and just threw on a kragen slashcut tip with a clamp until I can afford new exhaust. I noticed a week or so after, I have a HORRENDOUS exhaust leak at the manifold now. I am assuming it all shifted. I dont think its at the exhaust donut. Its the drivers side so there isnt too much stuff in the way. What is involved with fixing this? I am concerned about bolts breaking off when trying to remove the manifold.

 

The stock exhaust shouldn't have any gaskets. Are you sure you are leaking at the manifold to cylinder head flange? You are right in that old, high mileage exhaust bolts will break off, but a little bit of PB blaster and patience will have them out. I do recommend replacing them (cheap).

 

I cant say im 100% sure, but it sounds the loudest right in there. I have felt around the entire area and cant feel any air. It goes away somewhat when its completely warmed. We are kinda lost on how to find it exactly.

 

Are you hearing a popping sound or cracking sound? Is the AIR system and EGR intact? Sometimes an AIR or EGR leak can sound nasty.

 

The best way I can describe this noise is the sound of the TBI injectors but WAY louder. http://www.youtube.com/watch?v=uTmaQ...eature=related sounds pretty much just like this. On the drivers side. and a little more pronounced.

 

Do you see any carbon marks around any of the exhaust primaries to indicate that there is a leak?

 

I dont think so. I will thoroughly check tomorrow when there is light. My dad seems to think its that "donut". that collector flange or whatever its called. Since we had to remove the last hanger in the back to cut the tip of the pipe, it added pressure on that. I will check it out more tommorow.

 

Cutting the tailpipe will not make that noise. Also, GM didn't use any donuts or gaskets on TBI exhaust systems. It could be a missfiring cylinder. How is the drivability of the car? Despite the noise does it run okay? Is there any hesitation? That sounds could also be the pumping losses of a dead cylinder.

 

drives fine. same power and everything. I know cutting the tailpipe wouldnt make the noise, but we had to cut the last hanger off, and It must have shifted something or put added stress on something we are thinking. It all started shortly after that.

 

I had a similar if not the same problem. I thought it was just loud injectors until my step dad stuck his head in there and said "sounds like a exhaust leak coming from the drivers side manifold".Sure enough I checked the manifold bolts and the back two were loose. Tightened them back down and that fixed it.

 

I will check all the bolts in the morning when I have some light. thanks.

 

well I checked it today feeling around more. I found a loose or broken off bolt at the very back near the firewall...I am hoping it just backed out and didnt break off. Light is fading so I will get under it tommorow and check it out.

 

2nd bolt from the back was broke off deep in there. Then a couple others were loose. I tightened them down and the leak is gone, now I just have to worry about replacing that bolt sometime in the near future!

 

I think everyone should see this video. I was having that sound last year. Thought it was all kinds of stuff like lifter tap or more serious stuff. Eventually discovered it was just a loose header bolt.

 

Really glad you fixed the problem. At least its not leaking. Now the bolts being broken off is a hole different matter. Fixing that sounds like a Nightmare .