Exhaust Donut Gaskets
 

I keep burning up the little exhaust manifold donut gaskets. Is there a piece I am missing in there, all I have is the manifold and the flange that is welded to the exhaust pipes. I have replaced these twice and it will be quiet for about 50 miles then they burn out and there is nothing left. This is on a 22re and it is not running rich or lean or hot. has anyone else had this problem.

Most of the new ones are asbestos free, and not as tough as the old type ones.

You might see if you can find a solid metal donut of the correct size

Most parts stores will have a selection of them.

The metal ones will only seal well if the surface of the manifold and pipe flange are still smooth and not severely corroded.

I assume you mean the Exhaust Pipe Gasket 90917-06038 rather than the elastomeric suspension "donuts." http://www.toyotapartsoverstock.com/...rimLevel=18292 These are not maintenance items and should last the life of the vehicle; so yes, something is wrong with your truck.

The first thing I would suspect is a loose connection. The locking-nuts can literally wear out, and no longer grip the stud tightly enough. Vibration could open up the connection and beat the gasket to death. These nuts are about $1 each at the dealer, so consider replacing the ones you have when you replace the gasket. As millball suggests, you need to assure that the sealing surfaces are in reasonable shape; if not, torquing the connection will still not seat the gasket and its lifetime could be quite short.

And don't worry about asbestos; I don't think anyone has used asbestos in an automotive product in more than 40 years! The OEM gaskets were plenty good, and if installed correctly should easily last twenty years.

Most likely, as has been said, the gaskets are not seating properly and you still have a slight leak. The hot exhaust gases will quickly eat away a gasket if they are exiting out a small hole at high speed.

Below is a picture of an exhaust I worked on recently but for picture purpose and has since been fixed. Due to the issues that come up with leaks on them, I cut the pipe about 3 feet down. Getting the gaskets on while on the truck and getting them to stay while connecting the "Y" pipe is nearly impossible. I put the gaskets in the manifold first and THEN attach the "Y" pipe. I am not showing the gaskets, but I prefer the metal ones that tend to crush a little.
Attachment 118971

It cost me $25 to have my local muffler shop to weld the pipes back together and is well worth it to avoid the leaks to me.

Here is the reason I get to cut my exhaust system each time I pull the exhaust manifold. I use red locktite, then the Impact wrench and then I stake the nut to the stud. It beats having an exhaust leak at the manifold and pipe. The only leak I have to worry about is the manifold to head leaks which isnt often.
Attachment 118972

These will work but the ones I perfer are all silver. Not sure of the material. I got mine from the local machine shop.
Attachment 118973

i used the ones from the dealership, they seemed to work for me after I took off my y-pipe to weld a crack in the "Y". all the ones at parts stores were incorrect, I tried 3 different ones supposedly for my truck and they weren't the right diameter IIRC. i think having fresh studs/locknuts is also crucial in this repair, I was told they are one-time use only because they lock on.

if you let a leak go for a long time, it will get excessivly hot in the spot of the leak and warp it. i imagine that is what may have happened here. if that is the case, scuff up the gasket surfaces with sand paper or red/green scotch brite to shiny metal and use red rtv. it defies my teachings, but works on even 1/4" sbc headers.

Okay thanks for the info everybody. I am going to try and find the metal gaskets. I have tried 2 so far from autozone with no luck. I think I am going to cut the pipe like terry suggested because I just got my manifold back on with new nuts and studs after I heli coil several holes. should I use a little high heat rtv to just hold the donuts in place while I attach the bottom flange? I am going to get new nuts for it as well. The studs are in good shape and someone welded them to the manifold and I don't feel like torching them out.

i didn't use the rtv on mine, but then again they didn't leak afterwards with factory gaskets. i would in your case, especially where it leaked again. it doesn't get as hot as you might think, unless it is leaking.

Okay, I got it fixed. I drove to all the parts stores till I found some gaskets that would work. The ones I bought are about double the thickness of what they sold me the first 2 times. install was very easy I didn't have to cut the tail pipe. I just took the hanger bracket off the bell housing and pulled the bootom flange down till I had enough room to slide the new gaskets in and tada! I have a quiet truck again. thanks for you help everyone.

you didn't happen to get the part numbers for those thicker gaskets by any chance?

I think I still have the packaging on my work bench. I will look and post tonight.

Failing Exhaust Flange Gaskets
 

A common cause of these gaskets failing is a missing our broken mount between the bell housing and the exhaust pipe.