Exhaust Manifold studs

[rodo]

'82 with about 60K miles. Exhaust manifold is off. I understand that studs # 2 and 4 (if I have that right) are prone to leaking. Doesn't seem mine are leaking. Take them out anyway and reseal them? And what does one use to seal? I've seen several suggestions: silicone, tape, elmers glue. (Okay, not elmers.) Thanks.

[18Fiatsandcounting]

Yes, the top inner bolts (or studs) in the exhaust manifold lead to the oil gallery. #2 and #4 of the five. Some leak and some don't, but it's a good idea to put thread sealer on these. All you need is this or the equivalent:
https://www.henkel-adhesives.com/us/en/ ... e_567.html

-Bryan

[rodo]

Great, thanks. Got them both out and am now wondering about cleaning the threads inside. Read that some folks use brake cleaner. Okay, but how does one spray up in there without getting it inside the engine? More subtle way to clean those threads?

[18Fiatsandcounting]

I use old test tube brushes, gathered during my working days as a benchtop chemist. I also see these occasionally at dollar stores, and in fact you can probably find something similar at a hardware store.

All you need is a cylindrical bristle brush about 1/4" or 3/8" in diameter. Just put some oil on it, and twist it through the holes a few times. You could also use Q-tips or the like, I suppose, or even run some clean bolts in and out of the holes, cleaning the bolt threads each time. The bolts holes don't have to be pristine.

-Bryan

[rodo]

But if you put oil on the threads does that not negate the effectiveness of the thread sealer?

[18Fiatsandcounting]

But if you put oil on the threads does that not negate the effectiveness of the thread sealer?

Excessive oil, yes. A light coating that you wipe off, no. Just wipe the threads off with a clean rag as best you can, put on the thread sealer, insert the studs/bolts, and you should be good.

-Bryan

[rodo]

Bryan, you are the best. One last question...so I install the studs and...how far down do I tighten them? Surely there isn't a torque rating? Just until they snug up against the block when the threads run out?

[18Fiatsandcounting]

Yes, just tighten the studs so that the unthreaded part is against the head. I don't think there's a torque spec for this, but I wouldn't go any tighter than 18 or so ft lbs which is about as much as you want to torque an M8x1.25 bolt (stud) into aluminum. Honestly, I just snug them up and let it go at that.

My recollection is that the shorter length of threads is the side that goes into the head. If the threads in the head are partially stripped (it does happen), you can go a little deeper with a longer stud. Just don't bottom out the stud.

-Bryan

[rodo]

All came out, and back in, without a hitch. Thread sealer is curing. Thanks, Bryan.