Finding an exhaust leak?? (1 Viewer)

Joined
Jul 13, 2003
Messages
786
Location
Folsom, CA
I have tried several times to locate an exhaust leak in my 350 TBI FJ55. I have a nice scar on my left hand from feeling around the exhaust manifold looking for that leak. It is not noticable at idle, but is quite loud when accelrating. I am using 1981 corvette stock headers that do not use any type of fiber gasket with the exhaust pipe. I don't think the leak is there.
Below is pic of one of the manifolds.
Anyone have a 'trick' to finding the leak?
out of the pig.jpg
 
Joined
Mar 12, 2004
Messages
688
I use a stethescope with tubing connected to one earpiece and then tied or taped along the rod for rigidity. You run it all around the joints and listen for air passing over the tip. You have to isolate it from fan air.

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Joined
Mar 30, 2004
Messages
228
have you tried partially blocking the exhaust pipe (a soft soled shoe pressed onto the pipe by someone sitting on the ground will work) and listening? This should make the leak more noticable.
 

Pighead

Stop calling it an FJ
Joined
Aug 31, 2004
Messages
8,083
Location
Denverish
Maybe a length of garden hose? One end to your ear, poke the other end in and listen/feel for the leak?
 
Joined
Apr 19, 2004
Messages
123
Location
Colorado
I found an exaust leak using a spray bottle with soapy water in it. Bubbles indicate a leak.
This reminds me of that Far Side cartoon with the cave men holding meat over the fire with their bare hands. They look like they are in a lot of pain. Another cave man is holding his meat on a stick over another fire and one of the cave men says, "Oohh, look what Zog do!"
 
Joined
May 2, 2003
Messages
4,925
Location
GSO NC
As mentioned (kinda) ... zip tie a couple socks over (NOT IN) the tail pipe to give a little more back pressure and this may help with your quest.
 

Colorado Boy-74-FJ40

I may grow older but I refuse to grow up!
Joined
Aug 5, 2005
Messages
1,462
Location
Windsor Colorado
This may sound stupid, but it worked for me. I put a couple of smoke bombs in the tailpipe of my truck (white works pretty good). roll them in there at least a foot or so. When they start smoking really good ,blow the smoke into the exhaust with shop air or by mouth(dont burn your lips). Plug the tailpipe with a rag and turn over the engine with the starter. Don't let it fire off. (disconnect the coil wire) It will give enough perssure in the exhaust to force out the smoke wherever there is a leak. It really does work! You can do it over and over until you find the leak. You can also back pressurize the system with the shop air and find the leak that way, the only thing is that it will find open exhaust valves that way.
 
Joined
Sep 16, 2005
Messages
133
disconect your fan and run sea-foam through your intake... or any other carbon remover. should be @~2000rpm. you WILL see smoke at any leak.
HTH, carl
 

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