I installed new gaskets (along with Loctite High Temp Gasket Sealant) last year and now I have to remove the exhaust manifolds and throw them out (leak is still there), and replace them. The car was barely driven over last winter. Can I re-use those gaskets and re-seal them with the Loctite?

Are they the thick shiny metallic like gaskets...where was your leak @ by the way!

if there aren't many miles on the assembly, I wouldn't hesitate to reuse them (provided they don't get damaged duing disassembly.

due to the cost of new manifolds, you may consider taking them to a machine shop, and get them planed. not sure what that would cost, but I'd bet that would be cheaper. call around, see if you can find a place to do it, and ask for quotes.

@cmax
when the mani studs break, the mani can warp. when it's reassembled, with new studs/nuts and gaskets, they can still leak.

How can you tell where the exhaust manifold is leaking? I think I have a leak on the firewall side of the manifold, but cant really pinpoint it.

Yes, those are the ones. They are OEM and made by Ishino. The leak was somewhere within the exhaust manifold, not the flange.

I took a risk and in the end I wasted money. The problem is most machine shops wont pressure test them to see if there are leaks etc. I ended up paying for the decking of the exhaust manifold flanges (both), and after all that expense and new OEM gaskets and the high temp loctite and all new studs, the leak was still there immediately when I turned it on. It's likely a pinhole leak somewhere inside the manifold. I can't tell which one.

I've learned that on an old car like this, if it's something where the access is a major hassle and very costly in time, it can be pretty risky to re-use the old part.

It's hard. You can attempt the old plumbers trick by mixing 1 part water and 1 part dishwasher soap, spray the flanges soaking, then turn the car on (when it's completely cool), and look for bubbles. Have someone step on the pedal and watch. However, here is the horrible part. The putting sound can be a hole in the manifold itself (like mine), and you can't see it because of those heat shields that are either riveted on or spot welded covering the piping. So for me it was a gamble. At the machine shop the guy didn't want to remove the heat shields, because he said it would cost me more for him to weld them back together. I thought about using them without the heat shields, but then figured all the hoses would get burned up.

It's very hard to detect the firewall side, as you'll have to get the car raised up, then do the spraying, then look from underneath at the flange to see the bottom view. It may be hard to see the top view regardless.