Exhaust leak

Series I L27 (1992-1994 SE,SLE, SSE) & Series II L36 (1995-1999 SE, SSE, SLE) and common problems for the Series I and II L67 (all supercharged models 92-99) Including Olds 88's, Olds LSS's, Olds 98 91-96, Buick Lesabres and Park Avenue 91-96. Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.
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Detailpro116
SLE Member
SLE Member
Posts: 52
Joined: Sun Jan 21, 2018 1:18 pm
Year and Trim: 96 Bonneville SSEi
Location: Alberta, Canada

Exhaust leak

Post by Detailpro116 »

Since I bought the car there has been an audible fluttery sounding exhaust leak coming from the back side of the engine or under the car.

I'm ordering a ZZP downpipe soon, but I am assuming this exhaust leak is only the gasket where the exhaust manifold attaches to the exhaust pipe, as the leak is only heard under load.

If the manifold was cracked or leaking, if I'm correct, you would hear a constant ticking even at idle.

I just don't want to pull apart the exhaust and replace the gasket or install the downpipe and then find out it's the manifold, or replace the manifold and find out it was only a gasket. Haven't had a chance to be under the car to listen or look for the leak, but you can hear it only under acceleration or load applied. Probably just typing this out to verify my throught process lol.

On a side note, have any of you used the ZZP downpipe? I'm going to be ordering that, with the front power log and the ported throttle body.
'96 Bonneville SSEi - White on Teal - ZZP Stage 1 Kit, 3.6" Modular pulley, ZZP ported TB w/spacer, L3 short ram intake w/K&N filter, ZZP Power Log, ZZP DP w/high flow cat & 97+ manifold, ZZP SC coupler, ZZP HV ignition coils w/10.5mm plug wires, 16" Gold crosslaces w/Yokohama Avid tires, Olds LSS T-handle, Sony HU.

2000 Buick LeSabre Custom - Daily - Sony double DIN headunit, ZZP plug wires, ZZP TB spacer, L3 short ram intake - Dark Bronzemist Metallic on taupe
96 SSEi
Posts like a Northstar
Posts like a Northstar
Posts: 1813
Joined: Sun Aug 22, 2010 11:11 pm
Year and Trim: 2000 Bonniville SSEi L67
Location: Ontario, Canada

Re: Exhaust leak

Post by 96 SSEi »

assume nothing - get it up on stands and you may find the heatshield loose and rattling - see if you can recreate the noise with a helper holding revs
poverty forces one to do unorthodox things

2000 SSEi
past rides:
1996 SSEi
1992 GTP
1987 Grand Am
Detailpro116
SLE Member
SLE Member
Posts: 52
Joined: Sun Jan 21, 2018 1:18 pm
Year and Trim: 96 Bonneville SSEi
Location: Alberta, Canada

Re: Exhaust leak

Post by Detailpro116 »

Got all up in there. Leaned over the back of the motor and revved it. Can definetly hear the flutter coming from the gasket. You can see the gasket looks like it’s starting to fall apart on the top and that’s where you can clearly hear the leak. Problem solved. Now to spend money to repair lol. Going to be putting my ZZP order in within the next couple weeks.

Just spent my ZZP savings on a new fuel pump, EGR valve and fuel line repair on my new LeSabre. But that’s dealt with now.
'96 Bonneville SSEi - White on Teal - ZZP Stage 1 Kit, 3.6" Modular pulley, ZZP ported TB w/spacer, L3 short ram intake w/K&N filter, ZZP Power Log, ZZP DP w/high flow cat & 97+ manifold, ZZP SC coupler, ZZP HV ignition coils w/10.5mm plug wires, 16" Gold crosslaces w/Yokohama Avid tires, Olds LSS T-handle, Sony HU.

2000 Buick LeSabre Custom - Daily - Sony double DIN headunit, ZZP plug wires, ZZP TB spacer, L3 short ram intake - Dark Bronzemist Metallic on taupe
96 SSEi
Posts like a Northstar
Posts like a Northstar
Posts: 1813
Joined: Sun Aug 22, 2010 11:11 pm
Year and Trim: 2000 Bonniville SSEi L67
Location: Ontario, Canada

Re: Exhaust leak

Post by 96 SSEi »

so its the doughnut gasket where the downpipe meets the intermediate pipe? you can replace that yourself: not very hard 4 bolts iirc - rust is the enemy
poverty forces one to do unorthodox things

2000 SSEi
past rides:
1996 SSEi
1992 GTP
1987 Grand Am
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