Exhaust Manifold to Downpipe still leaks?

[zedjr10]

I replaced my 2 gaskets that go on the exhaust manifold to downpipe and it still leaks slightly in 2 spots in front corners. Both leaks are equal distance apart from front bolt. It is an ex so there are 3 bolts and not 2. Should i use some liquid copper on this?

[GhostAccord]

I have used copper never seize in the past and it has worked. Thing about buying a tube/tub of copper never seize is that you can use it on everything.

If that doesn't work, permatex copper should work.

[F22Chris]

I had the same problem. I took the header and downpipe both to a belt sander to make both flanges as flat as possible, then used permatex. Even torque on those nuts would probably help as well.

[zedjr10]

I have used copper never seize in the past and it has worked. Thing about buying a tube/tub of copper never seize is that you can use it on everything.

If that doesn't work, permatex copper should work.

I just got finished loosening it again and checking things out. I sanded down the mating surfaces a bit and tried reinstalling with same gaskets as they are only 2 months old. After i put it back together it still leaks. I didn't try using any liquid copper this time but tomorrow i am going to do it again and put some liquid copper in there. Why is this not working am wondering. These are oem gaskets and facing the right way. Flat surface towards outlet of exhaust. Right? How do i coat it with copper. Plop it in the spot first then spread some copper around it i suppose? Is that right?

[Ghostwhite]

I just got finished loosening it again and checking things out. I sanded down the mating surfaces a bit and tried reinstalling with same gaskets as they are only 2 months old. After i put it back together it still leaks. I didn't try using any liquid copper this time but tomorrow i am going to do it again and put some liquid copper in there. Why is this not working am wondering. These are oem gaskets and facing the right way. Flat surface towards outlet of exhaust. Right? How do i coat it with copper. Plop it in the spot first then spread some copper around it i suppose? Is that right?

The biggest reason is from warped flanges. Smear a bead of copper on surface of the flange in the area the gasket occupies, sometimes you need to do both sides of the gasket. Even tightening on the bolts and don't over-torque.

If you wanted to check the flanges you can put a straight edge from outer bolt hole to outer bolt hole and pivot on one of the outer holes and sweep in an arc watching for gaps.

[zedjr10]

Should i now get another set of gaskets.

[Ghostwhite]

Should i now get another set of gaskets.

It would depend on how much crush the gaskets have, the copper sealant is cheap enough to try with you're old gaskets if you want.

[zedjr10]

It would depend on how much crush the gaskets have, the copper sealant is cheap enough to try with you're old gaskets if you want.

i read somewhere they compress and uncompress. This diminishes over time i guess.Not so much crush and stay crushed. I wonder if this is true?

[Fleetw00d]

If you're using OEM metal rings, they do not uncompress.

[zedjr10]

A little tube that came off my air sprayer went down into downpipe and i couldn't retrieve it. I guess now i should disconnect before cat and blow the thing out of exhaust. It is about the size of those air nozzle attachments on pbj blaster, brake cleaner and so on. IS my cat a thin honeycomb design. If it is wont it just melt inside of cat?

[F22Chris]

Yeah get that out. Just take the manifold and downpipe off completely and flatten the flanges.

[zedjr10]

Yeah get that out. Just take the manifold and downpipe off completely and flatten the flanges.

i plan on just loosening the pipe before the cat and start engine to blow it out. I should of got it out before but i thought it might pass thru cat(stupid me).

[zedjr10]

Is it possible if i started engine that it could just pass thru cat and exit tailpipe?

[cp[mike]]

Is it possible if i started engine that it could just pass thru cat and exit tailpipe?

no, the catalyst mesh is way too dense to fit a straw through. Think of it like a kitchen sponge.

[zedjr10]

no, the catalyst mesh is way too dense to fit a straw through. Think of it like a kitchen sponge.

Yeah stupid impatient me. I thought most cats had a blow by space above and below the honeycomb structure(or at least i was hoping). Am hoping now i can take those 3 bolts off easily and flex pipe will bend down a bit to blow that straw out.