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Discussion Starter #1
I'd been hearing more and more of my beastly 2.9 as of late, and finally resolved to replace the gaskets on both ends of the exhaust manifold. Well my 169,000 mile truck had other plans.



There's a crack that goes all the way around the manifold between #2 and #3 runner, and a crack that splits off to run along the #3 runner. I considered welding it, but it's really only hanging together by 1/4" on the bottom. There's chunks of metal missing! My oxygen sensor was probably just a random number generator because of this. I looked in a salvage yard, and found a couple of 2.8's, which I'm not sure would fit, and were cracked anyway, and a 2.9, which was cracked, and a 3.5, which was pristine because of course it was.

I work in the metal fabrication business, and know some very talented welders, who told me what I had already kinda figured. It could be welded, but it may or may not last very long.

So I had to make a decision. Do I spend the $500+ (!!) on a stock cast manifold, and hope it's not cracked again? (It looks like a common problem) Or... do I order something shiny from Pacesetter for about half as much?

The new header will be here Wednesday, if Amazon prime holds up their end. I don't need the truck until Thursday, hopefully, I can get everything back together Wednesday. If I can't, it's not the end of the world, I'll ride the motorcycle.

Has anyone else put a header on their 2.9? Did it make a difference? Will I be under the hood tightening exhaust bolts once a week? While I have it apart, should I change the bolts out for studs?
 

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I have the same problem on my 3.5. Except, at my U-Pull yard I found one good 2.9 manifold, but no 5 cylinder manifolds! Too bad we're so far away. I'm in Savannah Ga, so the shipping would make it silly for us to swap. Basically, like we both understand, heat causes the manifold to expand and contract. This manifold has to be bolted very tightly to the head, so it has no room to move. Other members have use various tools to make to bolt holes larger or even just wider (slotted) to allow for a little movement to prevent these cracks. Mine is cracked on both sides of #3. So, it may be that the replacement header you ordered has oversized holes already, but if not this is a solution that seems to work, but I'd hesitate to modify something that I just purchased for hundreds of dollars. I would either replace the bolts or install studs. I probably would prefer studs. I broke two of the bolts when I took my manifold off to gut the pre-cat and to attempt to use muffler tape to patch the crack in my manifold. It lasted for about 6 months. I hate messing with broken bolts. Studs would fix that problem, but I'm sure you hope you never have to take it off again, but who knows.
 

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Discussion Starter #3
I have one bolt broken off in the head, there's about a half inch of it sticking out so I've been soaking it with PB blaster yesterday and this morning so I can attempt to remove it later today. It was broken when I went to pull the manifold, so I don't know how long it's been that way.

The new manifold is stainless tubing, instead of cast iron, if it cracks I can weld it up no problem - but stainless doesn't crack as easy as cast iron.

What I am glad to see, is the new part has the mounts for the heat shield. As cool as it would look to have a header exposed under the hood, I don't want to deal with the extra heat.
 

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Discussion Starter #4
Sometimes, you get lucky.



That's the broken off bolt that was stuck in the head by the #4 cylinder. Soaked it several times with WD-40, grabbed it with my daintiest vice grips, and started to wiggle it back and forth. It started to unscrew, so I gave it another soaking, and carefully, slowly, sensually, backed it out. I've got the mating surface clean, the holes blown out and run out with a tap, as soon as the pacesetter fairy makes an appearance, I'll fly into action, like an inebriated yeti with a socket wrench and tourettes, and slap it all together.
 

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and started to wiggle it back and forth. It started to unscrew, so I gave it another soaking, and carefully, slowly, sensually, backed it out. I've got the mating surface clean, the holes blown out and run out with a tap,
That's the sexiest talk I have heard when it comes to talking manifolds.
 

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Discussion Starter #8
About to tackle this exact issue on my 3.5. Hoping that I don't have any issues with the bolts. Every stuck bolt I've had has turned into a nightmare..

Been there, done that. Broke an exhaust stud off on a 12A rotary, of all things. Can't pull the head off of that, can we.

I also operate and repair a Mazak 300 Fabrigear tube laser. It has quite a few things that can go wrong/break. I've become pretty good at removing broken bolts, drilling and tapping, etc etc. However, it's a lot easier to get to most of the stuff on that machine than the associated fasteners on our little trucks.

I've run up against an interesting issue, however. It may be nothing, it may be a problem. It may require me to do some fabrication. I sent an email to someone at Pacesetter when this cracked manifold reared it's head the other day. He got back to me today, to inform me that he didn't have a header for the 2.9 engine.

Problem is, I ordered a header, pacesetter # 757517, from Amazon. It's for the 2.9 four cylinder, the part is pictured below and it certainly looks like it will fit. Can one of you more educated people tell me what horrible unworkable differences there are between the 2.9 manifold and the 2.8 manifold? I have access to some pretty incredible fabrication equipment, and if it was a case of the tubes being too far apart, and the flange being the wrong shape, I could make another flange in minutes, but I'd like to know what I should prepare for, in case I get a 2.8 manifold. It looks like one issue between the two is the two O2 sensor bungs - the header I've ordered and the manifold off my truck both have an upper and a lower O2 sensor.

 

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sharp looking header. keep the posts coming my 2.8 would love a exhaust redo.
 

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Is the 2010 too new to just pull the stock manifold off and replace it with a shorty header without O2 issues? That's what I did to my 05, no codes, no nothin'.
 

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Discussion Starter #11
Is the 2010 too new to just pull the stock manifold off and replace it with a shorty header without O2 issues? That's what I did to my 05, no codes, no nothin'.
I'm mostly doing this as a way to get the truck back on the road in a semi-now sort of timeframe, the header I purchased simply bolts on where the old manifold was, and attaches to the exhaust under the truck without modification.

My 2010 truck has two oxygen sensor fittings, one above the catalyst, one below it. I think if I'd replaced this with a non-catalyst part, I wouldn't have a place to screw in the 2nd sensor. It also might not attach to the exhaust pipe properly, causing a 15 mile open-header trip to the muffler shop, (midas) most likely to hear them caterwauling that it's not "stock" and they "aren't allowed to modify it" Come on guys, just move the end of the pipe six inches.
 

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Discussion Starter #12
The header fairy showed up a bit ago.



Doesn't weigh anything near what the old part did. Fit right up, top and bottom. This is pacesetter #757517 for the 2.9 liter engine.



I started the engine, and let it warm up. I figure I will heat cycle it a couple of times, then re-torque the flange bolts to 15 ft-lb. The truck is very quiet now. I haven't driven it yet, as the daughter creature is napping. When she wakes up, we'll take it down the road and see what happens.
 

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Discussion Starter #14
It's been ten months since the Great Header Saga was concluded. I'm sad to say, that the only issue I've had has been increased gas mileage, increased power, and reduced noise. I replaced the bolts with studs during the install, and haven't had any of them back off yet. The sound is subtly different. Not as much "forklift", more "rumble". The truck still has the rest of the stock exhaust. Noticeable increase in torque, the truck will just walk off with a decent size trailer now.

I've now got almost 179,000 miles, and I can say with confidence, don't but a stock replacement manifold if you can get one of these headers instead.
 

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Thanks so much for the feedback! We so rarely get this kind of info after the repair. I'm still in here in Savannah with the 3.5 with cracks getting bigger and truck getting louder. I've actually filled out the order twice for a stock replacement manifold, but cancelled it before supplying payment info. I need a good welded header like yours. I'm a realtor with 4 houses on the market for sale and I'm in the middle of a big house flip where I'm doing most of the repairs, so the money needed is on the way. Very glad to hear that the result was more than just getting rid of the racket! My MPG's have been disappointing for a while and a little extra bit of balls would be great too! My truck has 226,000 miles on it now and has been a great truck and does everything I need it too, even though I haule more than I should and pull a trailer constantly and always have several hundred pounds of tools, compressor, and all sorts of building supplies every day. Great Truck! Can't wait to get that header ordered.
Thanks again!
 
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