Header bolts removal

Dose any one have any advice for removing a stock exhuast manifold on a 91 4.3 The bolts have been in there since the truck left the candian factory. Kind of want to put headers on pluse my exhuast flange bolts are boken off in the manifold flange

I have had luck with lots of prep work... get it hot, spray penetrating oil on each bolt. Rinse and repeat daily for a month or more.

I hate exhaust bolts, worse than brake fittings IMO

Go into the job expecting to pull the heads to drill-out the broken bolts.

Go into the job expecting to have to torch or drill-out the broken exhaust-pipe studs.

That way it's a bonus and top-of-the-world feeling if you get the bolts/studs undone without breaking 'em. Penetrating oil on the studs is probably a good idea. Not sure it makes a bit of difference on the bolts going into the head. The oil can't really get into the cylinder-head threads to do any good. Makes a nice puddle on the ground.

When it goes back together, use brass or stainless nuts on the studs securing the exhaust pipe; and anti-seize on the bolts holding the manifold/headers to the cylinder head. Stud-and-brass-nut kits are available at any parts store. I've gotten them from NAPA several times.
Example:

thanks i ll just wait till the heads have to come off. One guy told me to heat the heck out of the engine. then try but he said read line it for a few mins ( the last part isnt going to happen at all)

Engine heat (combined with exposure to the elements) is what caused that hardware to seize to begin with. Warming-up the engine is pointless.

You wanna use heat, get an Oxy-Acetylene torch. That allows you to add tremendous, LOCALIZED heat, so that you can use differential expansion to your advantage. The point is to heat one item fast enough that the heat doesn't have time to transfer to the other item. Heat the piss out of the manifold flange where each stud is, one at a time. Remove each stud while the manifold is still glowing. The studs should be considered disposable. OTOH, if you're replacing the manifolds with headers, there's no reason not to just break the studs, you're not reusing 'em. You could try heating the bolt heads at the cylinder head end of the manifold; but I don't think you can expect miracles with them. You'll never get the bolts hot, deep enough to do any good. At any rate, heat the heads, then let 'em cool before removing.

Yeah, exhaust work often SUCKS. As I said, you need to go into the job with the attitude that it's all getting scrapped. Whatever you can salvage is bonus.

Xxl2 said:

One guy told me to heat the heck out of the engine. then try but he said read line it for a few mins

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Do I understand this right? The guy says to "red-line" the engine for a few minutes?

Good way to put rods through the side of the block, or drop a valve. Don't ask for his advice on automotive repair any more.

Xxl2 said:

stock exhuast manifold on a 91 4.3

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Rev the piss out of it for several hours may be the best solution to begin with

Schurkey said:

Do I understand this right? The guy says to "red-line" the engine for a few minutes?

Good way to put rods through the side of the block, or drop a valve. Don't ask for his advice on automotive repair any more.

Click to expand...

Trust me i stopped listening after he told me that. I posted that more for a laugh

id suggest getting a set of these especially if you plan to reinstall them. I did a head gasket on my 97 last year if I remember correctly they came out ok but 2 of the bolts were tight and didn't want to come out. I put the spreader on there to take some of the pressure off the bolts and it came right out. I tried to reinstall the manifold and it was unbelievable how far the manifolds were off after sitting for a few weeks. there was no way I could have got them back on without the spreader. I wouldn't have believed the manifold would change like that if I hadn't seen it myself.

tried everything, took it to the dealer.