Exhaust Manifolds Leak

[hankk]

My exhaust manifolds have been leaking for quite some time now. Finally ready to pony up the cash to fix this issue but it seems the Doug Thorley Headers are out of stock everywhere. They show as in stock on the XAT Racing website but when I ordered them they sent me an email saying they no longer have any in stock. I’m told Doug Thorley is likely discontinuing these headers but XAT is working on manufacturing a solution. No word on when this may happen though. Anyone replaced their cracked manifolds with new OEM manifolds instead of Doug Thorleys? I’m curious how they hold up and how long before they leak again. Curious if anyone has any advice on what to do here. As far as I can tell my only options are to replace with OEM manifolds and hope they don’t leak again or wait and hope XAT starts offering an aftermarket header solution.

If anyone happens to be selling a set of non VVTI Doug Thorley headers I would love to purchase them.

 

[TahoeZ]

OEM is the only option at the moment I believe. They will leak again eventually. If yours aren’t cracked and are just slightly warped you can also have them machined/surfaced flat and reinstall them.

 

[nissanh]

AVOID OEM. I installed an OEM manifold and the gasket by my self and it still have a leak! That is a poor design.

 

[diego355]

Put a Dorman in like 4 months ago, no issues and they come with lifetime warranty

 

[pavell]

I installed a new oem about a year ago, worked great but I hear good things about aftermarket too

 

[Snow Wagon]

The replacement process isn't fun, so whatever you do, you just want to do it once.
LC is a little easier than LX (due to AHC parts in the way), but still not easy.

Recently I've use only OEM, with OEM gaskets, studs, and nuts.
Supposedly Toyota has slightly improved the design / build quality.
I haven't had any leak and I've done 5.

Penetrating fluid is your friend.
Start spraying it on a week in advance.
Clean the ends of any studs you can reach with a wire brush.
Unless you have a completely rust-free cruiser, the heat shields won't come off easily.
I usually end up cutting them.

Figure out what combination of sockets / extensions / breaker bars / impacts fits where and take notes.
Start the SUV, let it get up to temp, then shut it off.
With it still as hot as you're willing to work around, start breaking nuts free.
Repeat this process a couple of times until you know all nuts / studs have been broken loose.
Spray them all one more time with penetrating fluid, then fully remove each one.

Heat is your best friend when removing the nuts / studs and there's no good way to get a torch on them, so starting the SUV is the best maneuver to heat them up (IMO).

Spend some time cleaning the mating surface.
It needs to be nice and flat with no leftover gasket material, high rust spots, etc.
Walmart sells a metal gasket scraper that really isn't bad.
I also have plastic razor blades, small flat files, and scotch-brite / 3m pads that I use.
Make sure you don't gouge the metal.

For assembly, use a torque wrench on Every nut.
I had a guy bring me his, that was leaking after he did the replacement.
All I did was loosen and retorque every nut and the leak went away.

There's several write ups on mud about how to access everything, but this gives you some helpful hints.

Good luck.
Tom