Exhaust manifold leak - Toyota 4Runner Forum

daprotege5 · 10-16-2022, 12:14 PM

05 4Runner 4.0, Recently replaced my exhaust manifolds with davico brand as I was getting p420,p430. so before installing talk to a friend and he said double up on the gaskets so it doesn’t leak. Initially did it and another friend said sounds like you have an exhaust leak. So following weekend I took out the extra gasket and left just the one.

My exhaust note changed somewhat, and feels like it’s lacking a pinch of acceleration it had previously. but no CEL, I never disconnected the battery, should I have reset ecu??

Also was looking into remflex gaskets, suppose to be a solution for warped heads or manifolds..

Anyone have this issue??

waypoint · 10-17-2022, 08:40 PM

Did you use a torque wrench and tighten the bolts to spec, in a radiating pattern from center outwards?

I've never heard of double-gasketing anything unless the service manual written by engineers specifically calls for it.

If you've ever seen what happens to oil filter sealing when the old rubber gasket stays stuck to the housing and results in double-gasketing, you'll have some idea what is likely happening at your exhaust manifold surfaces.

daprotege5 · 10-18-2022, 12:52 PM

Theirs only 1 gasket in there now. Actually I torqued them backwards from outside corner to corner, than did the inside.

gm350reratliff · 10-18-2022, 05:30 PM

I agree, don't double gasket anything unless it calls for it. If it still leaks, either the gasket is compromised/installed wrong, the manifold is warped, or the head is eroded where it was previously leaking. I would also recommend to leave the battery disconnected at least 4 hours so you can reset fuel trims, etc..

randy88fj62 · 10-19-2022, 05:04 PM

When I pulled my cracked manifold off I rewelded it and re-installed it with a new gasket. Never had an issue needing to reset the battery. I have also never heard of double gasketing.

I replaced the studs with new and installed copper lock nuts so if I ever need to take it apart again it won't be a hassle.

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