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Looking for some guidance on a possible exhaust manifold/header issue on my 997 after a rear-end accident.
Background:
Rear-end accident damaged the driver-side exhaust/tailpipe area
Driver-side tailpipe/muffler was bent downward.
Passenger side cat got hit and got dented
Muffler shop later used force to push/lift the driver tail pipe back into position.
More recently I replaced the cats myself.
During cat install, the bank 2 (driver side) cat pipe did NOT naturally align with the muffler inlet — I had to apply force to get the connection together.
Now I have:
ticking/exhaust leak at the manifold where it meets the head (felt the air come up from the area highlighted in the pics below - this gap/issue is towards the front of the car)
visible gap between manifold flange and head
no CEL or codes
car otherwise runs fine
Photos attached.
Question:
Could exhaust preload/tension from the rear impact + forced alignment be pulling the manifold/header out of alignment and causing this gap/leak? Has anyone seen a manifold flange warp or get pulled away from the head from downstream exhaust stress?
Trying to determine whether this is likely:
gasket only
warped manifold flange
exhaust alignment issue
or something more serious.
Also wondering whether I should avoid removing the manifold unless absolutely necessary because of the risk of broken studs on these cars.
Seems that the manifold flange has been distorted on impact, not making flush contact with the head. A knowlegable shop might be able to resurface the flange but it could lead to misalignment of the rest of the exhaust.
I pulled my exhaust manifolds last Oct to better facilitated changing plugs and coils.
Bolts came out no issue. (Manifold bold torque was only 17ftlbs)
New gaskets are cheap- I also order a new set of bolts ~$50 for both sides.
I've only had the 997.1 since Jan Oct, so I don't know what the entire history of maintenance has been regarding the manifold.
I'd start with replacing the gasket. Note you are also going to want to replace the exhaust manifold to cat converter gasket. Both gaskets run about $10 each.
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Exhaust manifold/header issue
