cheesemonk

2002 GS300
Just purchased mine! (preemptive thank you!)
I bought it with an exhaust leak that I hunted down to the exhaust flange gaskets ( by soapy water and a blower in the tail pipe. I purchased two new ones, installed, and the leak was coming out the bottom of the flange connector (by the bottom bolt). I assumed I messed up the install somehow (I hope I did so it's not something serious), but I sanded/wire brushed all the rust off and make sure the mating surfaces were clean as could be, used alcohol to further clean the surfaces and installed the gaskets. One thing I did notice was the bolts were not spring bolts, but standard M10x1.5 for all three. Should I get Toyota spring bolts? Or should I get some high temp silicone RTV gasket sealer and cover some of the metal surfaces?

I also had a small hole in the mid pipe literally on the weld for the down stream O2 sensor, I search the forums for this already and did not find anything about it, so I put some of the thermal steel paste on it and it quieted the ride quit a bit. So hopefully it's just the weird mating surface that can be fixed with the gasket sealer stuff.

Any thoughts?

Beau

salimshah

Congratulations.

Are we talking about the resonator (the large piece, before the tail pipe exits at the back)? The flange is straight nut-bolt. There is a grove for the gasket and one has ensure the packing sits in the groove (if it slips out, you will get a leak).

Most important thing is that the hangers must be aligned in a way that the flange faces are parallel to each other (the two halves that you are trying to bring together must be in a straight line. The faster just brings them together.

You can visit an exhaust shop and visit to the dealer is not necessary.
Salim

cheesemonk

No it's not the resonator, it's the flange from the header manifold, and going into the mid pipe. It's right behind the front wheels. I don't see a hanger until the rear wheels where there appears to be a brace going perpendicular to the vehicle. I will obtain pictures tomorrow for clarification.

salimshah

We are talking different location (there may or may not be spring loaded connection). But the flange connection is in 3 dimensions and for proper sealing the other two dimensions must still align.

Salim

captainva

iTrader: (1)

Did you buy a new factory exhaust gasket? The stock one disintegrates when it gets old

cheesemonk

I bought the FelPro ones from Orielly's. I installed them and they still leaked. Called Lexus and the parts were $15. I might use them instead. I've heard both great and awful things about FelPro, so I'm not sure what to do at this point.

captainva

iTrader: (1)

When I upgraded to my Toms exhaust I replaced the gasket with a Lexus one and haven't had any issues since. Make sure you get all of the old gasket off though or the new one won't seat properly

cheesemonk

Yeah I sanded it all down, used a plastic scraper to not damage the metal, wire brushed it, and used alcohol to clean it all. My gasket is super small though. Maybe a centimeter wide. The ones that were almost gone were the same thing, just rusted and falling apart. Link below to the ones I have, do they look OEM to you?

https://www.oreillyauto.com/shop/b/e...+flange+gasket

Thank you for all the replies!

captainva

iTrader: (1)

Is it made of a lot of metal rings? Personally I would just get OEM. $17 is not a lot and you can find it on Amazon

https://www.lexussouthatlantaparts.c...driveLine=8065

Alphaman19

cheesemonk

I rented one from Orielly's and did 36 FT/LBS. I couldn't find the direct torque so I used the manifold directions.
The flanges don't look bent, but when the vehicle is cold I shove my shop vac into the tail pipe and put a glove on the other pipe and spray soapy water on the entire thing. Nothing was blowing bubbles except for the O2 sensor hole which I used QuikSteel on to close up, and the flange area. As for the gaskets, I broke down and ordered the parts directly from Lexus. The old flange gaskets fell apart when I took them out, so I don't know how they were supposed to look, the Fel Pro seem very slim and carboardy though. I'll update tomorrow when I put everything back together. I might try to double them up too, or use some high temp gasket sealer/maker

Alphaman19

cheesemonk

So it wasn't he O2 sensor, it was the welding around it, it had an almost perfect round hole, which I thought was supposed to be there, but I guess not. The gaskets literally fell apart in my hand, but the shop vac was pushing enough to show bubbles and soapy water. I thought it was only leaking from the gasket, but once I replaced them (it quieted down a little the first time) I figured I'd spray everything since it's all kind of rusty down there anyway, and I found another hole.
I mean the gaskets shouldn't be leaking at all, right? It's not meant to let air past it?

Alphaman19

captainva

iTrader: (1)

Here are the torque specs