I have a 99' 4runner V6 & I have an issue w/ my flange gasket between the cat & the exhaust pipe. When I bought the truck in spring 2009 the gasket was leaking so I replaced it & this year it's leaking again. A mechanic I know said that the cat converters in these 4runners are notorious for a piece of metal inside the converter breaking off & causes these kinds of exhaust leaks. My friend told me that when he's driving behind me he can smell the raw exhaust & he told me that I should replace my catalytic converter. I am wondering if anyone in here had this same problem & need your advice just in case if it's just a gasket issue or it's really the catalytic converter? I just don't wanna go out & spend big $$ & the issue re-occurs.

 

are you buying OEM gasket? if your catalytic converter is dead your would get CEL and usually throw a p0420

 

No I'm not using OEM. When I went to my local parts store the first gasket that was listed for my truck didn't fit because it was like a small o-ring shaped gasket. So as I was looking @ the flange & it had an oval shaped style so I went back to the store & I requested for a chevy gasket & it fit right into the flange lol! Now I don't know if my truck has an aftermarket cat or if it came like that from factory.............

 

take a picture. if its oem cat, i would go to toyota a get an oem gasket. i havent seen any of those fail and alot of times you can just reuse them even tho the repair manual says to replace them if you remove

 

Hmmmm, I guess I'll take it to my local Toyota shop since I know most of the guys there & have them take a look @ it they'll have a better idea if it's aftermarket or OEM. No I don't have any engine lights coming on but I'll have them put it on a scanner to make sure.

 

if you dont have a cel than im sure your cat is fine. i would just use oem donut (gasket)

 

Oh okay guess I'll just buy an OEM gasket & see how it turns out. Does cel mean some kind of code or something?

 

CEL : check engine light

 

The exhaust bolts also need to be really tight. Mine leaked as well and I had to really crank the bolts to make a seal.

 

Use Copper Coat or a thin coat of RED RTV on both sides of the gasket. I don't even use gaskets on the exhaust in my '88, just a thin bead of RED RTV and I let it cure for a few hours before driving - no leaks in 6 years of use

stuff is great for high heat gaskets and helps fill imperfections

 

Be careful with gasket compounds of any kind. Copper and silicone (RTV) both are known catalyst and O2 sensor poisons.

It sounds like you have a non-OEM exhaust flange, so I'm not sure the OEM gasket will work.

-Dan