I replaced a majority of the exhaust, everything after the exhaust manifold (muffler, resonator, catalytic converter and flex pipe). I used Toyota part for the resonator, but aftermarket for the catalytic converter and flex pipe section, and the muffler. The aftermarket catalytic converter, I realized after almost completing R&R that the flange on the aftermarket catalytic converter that meets up with the OEM resonator section, did not have a recessed portion for the proper gasket. So I made my own using Permatex Optimum MAX TEMP. I I also put some on the exterior of the flange to ensure no leaks. I also did on the other flanges as well. I taped the shop vac to the muffler and blew air into the newly installed exhaust and got underneath the car, and couldn’t find any leaks. I also use anti-seize on the bolts, in the hope that I would be able to remove them later on if needed. I used Permatex copper anti-seize. I used silicone grease on the bushings that hold up the exhaust to make it easier getting the old exhaust off and the new one back on. I made sure to take off the stickers the best I could before installing the exhaust parts, so that none of it was left.
After starting up the car, everything looked great. I could feel exhaust gases coming out of the muffler, so I don’t believe it’s clogged. It did not get cheery red hot in any of the exhaust. I put a fire extinguisher in the car and did a test drive. I even got onto the highway and went for about a 20 minute drive. I did not smell anything from inside of the car or with the windows down. After stopping I got out of the car and noticed a somewhat burning smell but couldn’t see any issues. After I got home I noticed some white smoke coming out of the flange that connects the catalytic converter to the resonator.
What should I do? Should I just continue to drive for a few days and ensure that everything has “burned off” that would be causing this issue? I’m sure that the silicone grease that I used properly wasn’t rated for an exhaust. I used it only on the rubber bushings though. I did see a burnt rectangle area where the old stickers used to be. I used Permatex copper based anti seize that is supposed to withstand an exhaust so I don’t think it should be burning off. The Permatex 27038 is rated up to 750 degrees F, so I think that should be fine as well. I guess if I continue to see fumes coming from the flange after several days, should I just take more Permatex 27038 and go around the flange to ensure it is really not leaking? I used a torque wrench on every fastener using specs from the service manual.
Buy a flat exhaust gasket that seats where you put the Permatex. Make a template of the surface and take that to the parts store to find the closest match.
Thanks. On the OEM resonator there is a recessed portion on the flange (but there is not on the Walker catalytic converter). Would a flat gasket still work for me? I have seen these gaskets before. The only issue is that no dimensions are provided in part descriptions for these flat gaskets. Do they sell like a sheet of this material that I could just cut myself?
The part stores don’t have these gaskets on shelves so I would have to get behind the counter, and because they don’t have descriptions of dimensions, might be a bit difficult.
Both sides are like this. Completely flat. So it looks like two of them came this way so may not be a manufacturing error. Very strange indeed. This is a Walker 55603.
Thanks I tried several aftermarket gaskets that were supposedly correct. I clamped down them and it was clear it was to thick. After great frustration I gave in and bought the OEM part.
The proper gasket from the dealer. Gave them my VIN and they told it was part number 90917-A6001
But even this seemed to thick, but inner diameter and outer diameter correct. I concluded that the catalytic converter was just what you get with aftermarket part and it was supposed to have the recessed area at the flange. The only thing I could think of was to find a gasket with the same dimensions but half the thickness at 0.10 inches. Were with the OEM catalytic converter would have the recessed out area, and 0.10 inches would sit in the catalytic converter flange and the other 0.10 inches would sit in the resonator flange, allowing the two flanges to meet and be flush up against each other after using the fasteners to specified torque.
I couldn’t find a gasket with inner diameter of 2.39 inches, outer diameter of 2.91 inches and a thickness of 0.10 inches. So I’m stuck. I guess I can continue to look for one as I only spent a few minutes, and I cannot find a tool to sort gaskets by dimensions online to buy one. Some descriptions don’t even list the dimensions. Unless the flat one would work? Hopefully I can buy a sheet of that stuff?
I couldn’t get that wire out, so i am just going to return it.
Indeed. Looking at my old exhaust at the flange for the section of pipe that joints the flex pipe and catalytic converter section to the exhaust manifold, I see a recessed out area for a gasket. So presumably the other end also has one, while on the aftermarket one none of the flanges have recessed out areas for a gasket.
Not much experience with exhaust system repair, but as a diy’er it seems like the best method would be to remove the entire system from (& possibly including) the exhaust manifold to the end of the tailpipe, and repair the whole thing on the bench, then slide it under the car & install the whole system at once. Did you do it that way? If the only problem is the lack of a flat gasket of the proper shape, I wonder if you can just buy the proper kind of exhaust gasket material and cut it into the shape you need?
My preferred local auto parts store has a big book of gasket shapes. Sometimes I’ll take the old damaged gasket and they’ll match it up to one of the shapes, then they order it for me. That method has always worked, but I haven’t needed to use it for exhaust gaskets.
Hey thanks. I might have to try the flat gasket route.
An interesting thing I noted, is that aftermarket exhaust parts, the ones that don’t have a recessed cut out, recommend a 3D gasket that is partially metal, and not a flat one. Meaning when you clamp down on the two flanges, they will not be flush with each other. Almost like this is intended. This does not make any sense to me. Is this really ok? Meaning when you look at the flange after assembly you will see the following:
I always thought that it was supposed to look like a continuous pipe after assembly. I’m a bit confused by this. Check out Walker 47847 for a resonator and 31585 for the recommended gasket and walker 53602 for the recommend muffler
The recessed out area is only on the muffler only.
So I guess really my question is the recessed area supposed to be on both ends of the flange? I guess it doesn’t really matter as long as it’s on one end of the flange and the gasket chosen can be accommodated.
No exhaust connection I have ever encountered in my life has the two flanges touching each other after proper tightening. You’d have to bend the flanges using a flat gasket and a donut is normal to have a gap with the gasket captured in-between.
You have a mismatch between end types apparently. Time to get creative. However, no RTV type of sealant is going to work on exhaust and even if you do use it, they cure with humidity and will take some significant time to fully cure.
It’s normal to have a visible gap between flanges as a result of the thickness of the gasket? From what your saying, yes.
I just want to be sure, because my original one, there was no gap as a result of the gasket. The gasket has a thickness and is a piece of metal that cannot compress. I think my original one, had a recessed area on both flanges, so that when tightened down, both flanges were flush with each other, and the thickness of the gasket was accommodated by the recessed out areas.
But from what your saying this not necessarily required, and the gap between flanges from the thickness of the gasket is ok? If that’s the case, then I can just put any gasket in between the two flanges, as long as it’s the right inner and outer diameter, and the thickness does not matter? The gap between the two flanges does not matter.
I was attempting to use the metal ring type exhaust gaskets. I assumed they were to thick because of the mismatched flanges and the resulting gap between them. But sounds like it’s not an issue with the ring type?
I was also wondering. My old exhaust, original bolts didn’t appear to be spring bolts. But I could tell that the fasteners on the exhaust manifold to the section of pipe that contains the flex pipe and catalytic converter were a stud and nur. The original ones were still in excellent shape. But looking at the service manual, it seems like they are normal bolts and nuts used elsewhere in the exhaust system. Would upgrading to spring bolts be worth it?
Spring bolts is what was mainly used to allow the exhaust to have movement without using a flex pipe… So unless all your motor mounts are broke and your engine is twisting and moving around like crazy you are probably good not using them while using a flex pipe…
I also just want to make sure. When using a ring type exhaust gasket. It is ok to have a gap between the matting flanges? I know the matting flanges have a recessed area sometimes so that when you put the gasket in there the flanges are flush with each other, but if it is not possible it’s ok to have a gap there because of the ring type exhaust gasket.
That method worries me a little. If an exhaust valve happens to be open, it seems like the shop vac could blow some carbon grit lodged in the exhaust system back into a cylinder. What do others here think? Am I over-worrying?
But can anyone confirm that when using a ring type gasket (not donught) in your exhaust, you do not need to have the flanges flushed against each other? The ring type gasket is metal and won’t compress, resulting in a gap between flanges, unless you have a recessed cut out area in the flanges that can accommodate the metal ring.
