repairing manifold cracks on a 2.7

Im new to the group but i have been a reader for a long time but i figured why not ill share a story of my week.

Ive had a busted manifold like loads of other people on here and i decided to be done with the problem and i ordered a new stainless header online but i figured while i wait for it to come in why dont i try some of the cheap fixes that countless people are asking if works.
so i removed my manifold and headed to the parts store and stocked up on a few things that say they repair exhaust but any mechanic that cares about there work never look twice at.

so after just a wire brush clean here is my cracks im working with.



i decided to start with everyones favorit go to product to repair anything on a truck that should never be used, JB Weld (original).
normal JB Weld has a melting tempature of 500 degrees and exhaust manifold get well into the thousand range, but i still found a bunch of people that still want to try so here i go.

i cleaned the manifold up, mixed the JB Weld 50/50 and put down a very generous amount on the cracks and spread it wide, let it set for a full day in this arkansas sun and i was ready to throw her back on.


i fired the ol girl up and i couldnt believe it, it was quiet! i drove it around town and all was well beside a horrible smell it was putting off but hey i can live with it.
i started off to town the next day made it about 15 miles and started hearing a very familiar sound and as i went it just kept getting louder and louder till it was just like when i started.
i pulled the heat sheild and it turned to dust and just blew off from the heat (kinda new it was going to happen.)

next on the list was JB Weld extreme heat! says right on the package perfect for manifolds! lets see. i puller the manifold back off, cleaned her back up and followed the directions perfectly. i ground out the crack and gave it a rough surface to it to bond too. yet again i gave more than what was needed to give it the best chance at working.



next day i threw her back together together, fired her up, and just like last time it was quiet (for now). i drove it around and it was holding up great and wasnt burning away at all unlike its avarage counterpart. i actually believed it had worked until i took it down a dirt road and this stuff litteraly was falling off in chunks untill all that was left on the manifold was the JB Weld that wasnt even on the cracks at all!
so then it was time to try out the muffler cast exhaust bandage......... it was a complete joke and a waist of time not only did i not get to test it but i couldnt even get it to stay on the manifold through the instalation!

i then tried the last repair on the my list. i pulled out the mig welder, cleaned the manifold back up, put my helmet on, and welded her up. honestly only took 15 minutes. i went ahead and put a coat of flat black exhaust paint on it and threw it back in the truck. and the exhaust leak is compleatly gone and i can ride quietly until my new header comes in and i can replace that old junky cast iron manifold for good.


my point in this whole thing is, if your manifold is cracked and it bothers you so much that you cant stand it, dont waist your money or time on these cheap products that claim to work because if it does work it wont for long if at all. there is only two actual fixes to this very common problem and that is to ether weld it up right with a actual welder or braze rods. or buy a new manifold/header, and that is it!

stay safe people!

 

LOL. Mine cracked and I replaced it with a cheap assed PaceSetter header. It’s lasted a few years but I’ve have to change the 2.5” collector gasket 4 times. This last a fe days ago it still would not seal off due to the little 3 hole flanges being bent over from trying to seal it off. So I looked around at headers and manifolds then decided to go turbo. But I couldn’t resist a try at this header while I wait for all the turbo bits to arrive from all around the planet.


Will this one work? I haven’t a clue. I stumbled across it months ago and couldn’t get detailed measurements from the vendor but the same pics showed up over on Alibaba/AliExpress/whatever it is. So....it’s probably gonna have Chinese shipping labels. But WGAF. $200 is dang cheap for a solid header. Only issue is it’s not emissions friendly unless you weld in the EGR flange.

This is for a Prada which is basically a GX470 but with a 4banger. I have one. So I measured from each A arm to the opposite side on both the GX and my Tacoma and they were basically a 1/2” difference. I didn’t remove ththe skids, so it’s likely the same.

https://www.ebay.com/ulk/itm/253815481465

 

For $200 a Toyota mini header is as good as it gets unless boosted.

 

True dat. But I’ve lost my short pipe over the years and figured I’d give this full size a try.

 

You have to heat the case up first..I have mig welded manifolds with good luck before. Do the grinding and vee of the crack first like you did. Then you have to heat the cast up. I use the oven at 450 for about 30 min. Take it out and weld it immediately. Reheat and then let it cool down in the oven.

 

Solid advice. You can also drill a hole at each end of the crack and sometimes they won’t run on you while welding if not preheated enough.