Permatex 80333 Muffler and Tailpipe Putty, 4 oz.

This product will work, but you need more direction than the instructions on the package or their website. I think most of the poor reviews come from people who followed the vague instructions on the package causing the product to fail.The important property of this product is that it cures in 2 stages.Stage 1, water dries from the putty.Stage 2, the putty cures/hardens from high heat.During stage 1 it is critical that the temperature is below 212. If the temperature rises above boiling, the product will swell and fall off the pipe. The package states to start the engine and let it idle. That will work to speed stage 1 but if it gets over 212, it will look like the exhaust is blowing the putty off of the pipe. If you notice it rising like cookies in the oven, shut the car off, take a tool and push the putty back in place.Stage 1 is the complex stage. How long it takes will depend on the amount/depth of putty you use. If you can use starting the car to speed stage 1 will depend how hot the engine gets the exhaust pipe at the repair. If you are in front of the muffler, I would not use the engine. My best guess is wait 2 days. You could use a blow dryer or a trouble light to provide a safe heat. The putty will become hard during stage 1, but I don't know of an indicator that you have finished stage 1. The real test comes when applying the curing heat of stage 2. If it doesn't swell, you finished stage 1. If it does swell, just reshape it and wait longer to apply heat over 212. The putty will stick to itself, so if it swells and you want to add more of it to the repair, it will stick/join the existing putty.Stage 2 is simple, if you have completely finished stage 1. All you need to do is drive and the heat from the exhaust will cure the putty to a tough waterproof seal. (If it swells and falls out, you didn't finish stage 1)My only concern would be if the putty is not heated enough from driving, it would not cure. I do not have any input on this as my repair was close to the engine and over 1000 degrees while driving.My repair has lasted 30 days and it seems very solid. I hope that you can experiment with this product and find a method that works. My repair was to a very solid header pipe that only had a hole due to a heat shield that was spot welded on and rusted out at the spot welds. The product is cheap and easy to work with, about the consistency of toothpaste. Until you pass stage 2, the putty is still water soluble. If you need to soften it, just add water.I would recommend going to[...]to make a correct choice on the product you need. You can also find additional instructions for the products.

I have used this numerous times on cracked exhaust manifolds and even holes in manifolds and cats. I find the best thing to do is to try to find a course thread screw that fits tight in the hole and make a little sheet metal washer for it and screw this into the hole. Then the surrounding area must be wire brushed, sanded and sprayed with brake parts cleaner. I then layer furnace cement or the other high temp steel manifold epoxy that comes in a tiny plastic can over all of this, allowing it to dry. I then heat it several times with a heat gun. After this has cooled I idle the engine for small periods of time and allow it to fully cool. After this has all hardened I then coat the furnace cement WITH THIS as furnace cement and the other epoxy are NOT waterproof even after curing they deteriorate when wet. This is much more water resistant and also forms a much smoother even coat over the cement (if the appearance matters to you). After hardening I do the heat gun and idle/ cool cycles for this to cure. Finally I use high temp ceramic manifold paint over the repaired area. The problem with furnace cement and other products the hold up better to direct exhaust gasses are they are water based and resolve when wet. I give this 4 stars as it can be hard to apply (sort of a sticky toothpaste consistency) and it tends to crack and flake off if directly exposed to the hot fumes.

This is my first time using this kind of thing, and I screwed up. It works great, but I still screwed up. I made the mistake of soaking the entire roll when I planned on using it in two places. Bad idea. This stuff gave me what seemed like 4 minutes until it was too hard to unravel. I was able to wrap only one part of my exhaust (about a quarter sized hole) in that time. When I went to wrap another area, it was already hard as a rock. If you are using it in more than one place, cut it to length before you soak so you don't make the same mistake I did. Thankfully the other area I had to patch already had exhaust putty over it, and had a much smaller crack, so it's not a big deal.As for the product itself, it seems to be working great. It's hard as steel and does not seem to get particularly hot. I don't expect any issues down the line. No blow through or anything to make it seem like it can't deal with the heat. I will update my review in the future though.

Works temporarily, probably a few days until you can get it to a shop. Used it for a pinhole on my tucks exhaust . It's rated for high heat resistance but it did not hold up at the rear of my exhaust where the heat is not as high as the exhaust manifold.

I used this very successfully to seal pipe thread on a boat exhaust by applying to the threads before assembly. It has many hours of use and is working well. It's in the first threaded junction off the exhaust manifold so the hottest area with the most vibration. I'm very happy with the ketchup consistency when used as a sealer during assembly.I first tried to glob it over the threads as a quick fix, which would be similar to what I expect a repair on a car would be like. It was somewhat thin (ketchup consistency) and very brittle when fully cured. Also, after curing when it breaks the pieces are extremely sharp - like flakes of obsidian. There may be other epoxies with a slightly lower temperature rating that are less brittle that would be better suited to covering rust holes and stuff like that in an old car exhaust.