6th Gen ('00-'05): Exhaust manifold repair questions
#1
Exhaust manifold repair questions
Hello all,
I have a 2000 Monte with the 3.8L. It has an exhaust manifold leak somewhere in the rear manifold. How hard is this to change out? Cant find any videos on the web. There is no friggin room between the motor and firewall to get to the bolts! I'm an adequate do it your selfer but damn this one looks like a b!+<#!! Should I rock the motor forward or is it possible to rotate the motor down for access? Anyone else out there ever replace the rear exhaust manifold? Any opinions or advice would be appreciated!!
I have a 2000 Monte with the 3.8L. It has an exhaust manifold leak somewhere in the rear manifold. How hard is this to change out? Cant find any videos on the web. There is no friggin room between the motor and firewall to get to the bolts! I'm an adequate do it your selfer but damn this one looks like a b!+<#!! Should I rock the motor forward or is it possible to rotate the motor down for access? Anyone else out there ever replace the rear exhaust manifold? Any opinions or advice would be appreciated!!
#3
Thanks for the info! The flex pipe should allow that movement of the motor yeah? I still have no idea if it's coming from the manifold at the head, the gasket, or the flex pipe itself. Is there a gasket between the manifold and flex pipe as well? If so I'll go ahead and change both. But I definitely want to pull the manifold out and inspect it and go from there. Thanks again for your time brotha!
#4
Yes, there is a gasket at the head and where the downpipe bolts up. Between the flex pipe and the rubber hangers, the exhaust can move a ton, you should be able to rock the engine forward far enough to easily get your hands back there.
Also, unlike the front cast manifold, the rear is a bunch of welded pipes. It's not common to have a weld crack / leak form but it wouldn't be the first I've seen either. Definitely should be able to tell pretty easily if there is a real sooty area on or near a weld.
Also, unlike the front cast manifold, the rear is a bunch of welded pipes. It's not common to have a weld crack / leak form but it wouldn't be the first I've seen either. Definitely should be able to tell pretty easily if there is a real sooty area on or near a weld.
#5
Yes, there is a gasket at the head and where the downpipe bolts up. Between the flex pipe and the rubber hangers, the exhaust can move a ton, you should be able to rock the engine forward far enough to easily get your hands back there.
Also, unlike the front cast manifold, the rear is a bunch of welded pipes. It's not common to have a weld crack / leak form but it wouldn't be the first I've seen either. Definitely should be able to tell pretty easily if there is a real sooty area on or near a weld.
Also, unlike the front cast manifold, the rear is a bunch of welded pipes. It's not common to have a weld crack / leak form but it wouldn't be the first I've seen either. Definitely should be able to tell pretty easily if there is a real sooty area on or near a weld.
#6
Join Date: Apr 2010
Location: Mentor, Ohio
Posts: 12,156
Do you know if the leak is head to manifold? Manifold to downpipe? Manifold to EGR? Manifold to Cross over pipe? Or a damaged manifold?
Each one presents it's own issues. Two weeks ago, I resolved an issue with a loose connection between the rear manifold and the down pipe. I did it all from under the car. Since my car does not see any winter weather and I spent a couple days hitting the hardware with PB Blaster, it all came apart pretty easy. New gasket, replace some hardware and all good.
I found my leak because I suspected it (sounds louder than it should have). While under it for other reasons, found I could rock the downpipe at the rear manifold connection, just a little.
Each one presents it's own issues. Two weeks ago, I resolved an issue with a loose connection between the rear manifold and the down pipe. I did it all from under the car. Since my car does not see any winter weather and I spent a couple days hitting the hardware with PB Blaster, it all came apart pretty easy. New gasket, replace some hardware and all good.
I found my leak because I suspected it (sounds louder than it should have). While under it for other reasons, found I could rock the downpipe at the rear manifold connection, just a little.
#7
Do you know if the leak is head to manifold? Manifold to downpipe? Manifold to EGR? Manifold to Cross over pipe? Or a damaged manifold?
Each one presents it's own issues. Two weeks ago, I resolved an issue with a loose connection between the rear manifold and the down pipe. I did it all from under the car. Since my car does not see any winter weather and I spent a couple days hitting the hardware with PB Blaster, it all came apart pretty easy. New gasket, replace some hardware and all good.
I found my leak because I suspected it (sounds louder than it should have). While under it for other reasons, found I could rock the downpipe at the rear manifold connection, just a little.
Each one presents it's own issues. Two weeks ago, I resolved an issue with a loose connection between the rear manifold and the down pipe. I did it all from under the car. Since my car does not see any winter weather and I spent a couple days hitting the hardware with PB Blaster, it all came apart pretty easy. New gasket, replace some hardware and all good.
I found my leak because I suspected it (sounds louder than it should have). While under it for other reasons, found I could rock the downpipe at the rear manifold connection, just a little.
#9
It's certainly a possibility depending how bad the leak is. Any kind of opening to atmosphere ahead of the upstream O2 sensor can cause it to skew fueling as a result.
#10
That makes perfect sense. Considering the 02 censor is probably all out of whack due to the exhaust leak. It was running pretty damn good before this. It did have a cylinder misfire (stored in codes) in one of the cylinders back there. But didnt have an issue like now with the uneven idle and throttle hesitation. But the noise I'm hearing from the manifold screams big leak! Gonna change plugs n wires while I have access as well. Any other component that you guys can think of that I should disconnect before rocking the motor forward? Thanks again guys!
Last edited by Jesse Smith; 06-13-2019 at 11:35 AM.