Exhaust Manifold questions (20R)

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Murphy, TX
I've been tracking down/fixing some exhaust leaks and now I have come to the primary leak. When I hold my hand up against the heat shield I can feel exhaust air coming out a couple of the open ports (see pic), so I assume I need to replace the exhaust manifold gasket. I've done some research and have been reading horror stories about the studs/nuts backing out and stripped out stud holes so before I tackle this job I wanted to ask some questions and get some opinions.

I'm not finding Toyota OEM gaskets in my searches. Rock Auto and NAPA show that they have Felpro as a replacement. Is that a good brand? Any other recommendations?

I'm reading that the OEM exhaust stud nuts are a one time use only. Should I replace the studs as well? Yotashop.com has a complete stud kit. Seems kinda pricey, but I'd rather do this one time.

I'm planning on soaking down the exhaust studs for a couple of days before I attempt to remove them. Any other tips that might prevent problems?

Thanks.

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pappy

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I would not replace the studs unless you need to. Ya know, if it ain't broke. Yes, they can be a problem. Oh, wait, they are a problem after 40 years. Just be careful, and as you are doing, soak the crap out of them. Go buy a lottery ticket if you get them off without issue. Ya, replace the nuts, and I would run a die over those stud threads.

As far as gasket, I'm surprised Toyota has disco'd it. Felpro is fine as a backup. I did see that Rockauto had other options.
 
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pappy

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Oh, those studs are M10-1.25 if I remember correctly. You might start researching the installation and source of Helicoils/Recoils/thread inserts.
 
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On a positive note, your engine looks pretty clean and you're not in the rust belt.

"Sometimes" the studs will come out with the nuts. I think that's a good thing even if the threads in the head are gone. At least you won't have to drill out a broken stud.

If you have to have it up and running because it's your DD, get some studs, nuts and Heli-coils or other thread inserts before you start. Good luck.
 
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Thanks for the input. I got the heat shield off and had a look. There are supposed to be 7 studs holding the manifold on and sure enough there is no stud back by cylinder #4 where I was feeling the exhaust air. Also, as is usually the case, looks like someone has been in here before as I have a combination of 2 studs and 4 bolts holding the manifold on. Not sure if having bolts instead of studs helps me in trying to get them out. Starting the soak process. This is not my DD, so I am going to spend quite a bit of time soaking before I try to loosen anything.

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pappy

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Don't ya just love previous owners?
 

pappy

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Also, in your pic, the one stud/nut combo doesn't look right. The nut is wrong, and I think the stud is too short. I wish I had part numbers for you, but the studs used on newer engines have a torx head on them. That lets you install them easier. Plus, you can hold them in place while you remove the nuts.
 

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