Strange Exhaust System Putty / Gasket Maker

[1993_VG30E_GXE]

When I got back my Honda from the garage, I notice they used a strange putty or gasket maker in between the CAT & Resonator pipe. I don't know if they used this IN PLACE of the actual donut gasket, but does anyone know what this stuff is?

It dried REALLY hard when I touched it. It was grey color. Didn't feel like RTV.

 

[GearJammer]

Sounds like some sort of epoxy. I probably wouldn't take my car back to them again.

 

[1993_VG30E_GXE]

I called them, they said it was "muffler cement". What is this stuff? Can it work on the exhaust manifold flange to Cylinder Head.

I asked the mechanic and he said you can, you can put it over gaskets too to ensure a good seal. Wonder if this stuff is any better than the 700 F Loctite Copper RTV.

 

[willix]

It is muffler man hack putty. It is clay with chemical drying agents in it so it will set up fast, there was still a leak and they bandaid that on there to plug it up. Don't worry it will blow out. That way they can reuse the gasket or donut.

 

[eljefino]

Orange RTV is the way to go. That clay stuff is from 1920. And it's nasty to use. Not too far off from stove cement you'd fix a woodstove with.

 

[willix]

The high temp gaskets go on dry. They are usually a graphite/tin sandwich type or steel with a crush bead around it for a flat gasket. A spring mounted donut goes on dry. If they used a new gasket the ears of the flange were over tightend distorting the flat surface and should have been straightened or ground flat again.

 

[1993_VG30E_GXE]

Thanks guys. That's what I'm thinking eljefino - I checked my exhaust manifolds and the Orange Loctite RTV never burned off. Seems like it's holding up OK.

Re: Exhaust Manifold Flange
Willix, the high temp exhaust manifold gaskets can go on dry, but when the engine is removed on a stand, and I'm putting in new gaskets, there's no way I would risk installing them dry in case there was a slight irregularity. Nobody would remove the engine again to re-gasket it to get rid of an annoying putting sound.

RE: Cat Flange
I totally hear you on the resonator to CAT flange though, bending when tightening. It happened to me when I installed it to torque new. Problem was, I couldn't torque it down even with less torque without it bending slightly, and I can't just hand tighten it or the hex nuts could rattle loose.

I think the shop said, if they don't put the donut gasket in, they use the grey muffler cement. He said they didn't put in the Bosal donut. The grey cement is sandwiched in between the flanges, and alot squeezed out then dried.

 

[andyd]

I have used the Orange RTV with great success in cobbling together the cat backs. Never tried it forward of the cat.S'posed to be good for 500F.