T-stat housing bolts

[FullBlowncustoms]

Dealing with steel bolts and aluminum intake is a PITA sometimes. They expand and contract at different rates and corrode differently. You can drill them out and tap to the next size up. There is plenty of room under there to clean out the debris. If you do that, use some anti seize on new threads. Not a bunch, just a dab. Luckily, access to do all this, is wide open. Or, spring for a new intake and gaskets.

Had same problem before on wifes 85 Eldorado head bolts many years ago, Aluminum block.

 

[FullBlowncustoms]

Well, I tried everything I could think of and got a whole bunch of advice from other folks, and everything failed. Both bolts are broken off now, and the truck is at work over the weekend. We used heat, all kinds of penetrating oils, vibration, etc. Even tried welding nuts to the exposed threads. So, she's stuck till Monday and I got a loaner to drive for the weekend. More bummed than mad....never had an issue like this working on the old small blocks. Now I know why everything else was replaced EXCEPT the thermostat!

Try melting crayons, Candle wax etc in to the studs,

 

[FullBlowncustoms]

Being vertical studs done correctly, it will trace down in to the threads... Then weld good nut on top to remove stud.

 

[Schurkey]

the housing bolts are mega tight. I've been applying a good amount of force with my long handle ratchet and they won't break loose. Since the intake is aluminum, I'm afraid of breaking a bolt off or pulling the threads. They've been soaking in PB Blaster for an hour now. Anyone have some advice?

1990 TBI intake manifold? The Treasure Yards have plenty of 'em. And...your intake gaskets are probably due to be changed anyway along with the heater connector at the right-rear.

Drop the block drain plug on the left side, the knock sensor on the right side. Do a coolant flush at the same time as the thermostat and heater connector, as part of the intake manifold swap.

Heck, you could probably get a new serpentine belt and tensioner while you're in there.

Fresh gasket under the throttle body. And check the distributor for a broken magnet. No time like the present to swap distributors since it's coming out anyway.

With the intake off, you could pull a couple of lifters to check for excessive wear, and look at some cam lobes as well.

Pretty soon, you've got a new truck.

Realistically, I'd drill the broken bolts as described previously. IF POSSIBLE, drill using the size bit you'd use for tapping that size hole. See if you can then pull out the threads. MIGHT be possible if you're on-center, but the threads are maybe corroded right into the aluminum of the manifold. IF the hole goes all the way into the water crossover--some do, some don't--a heli-coil may perpetually weep coolant as the coolant works it's way around the thread insert.

But then, this advice is coming from a guy who spent two months drilling two broken bolts out of a rear-axle driveshaft yoke, in order to save a 90-dollar yoke. I should have bought a new yoke, and saved 56 days of crying and bit_ching.

I put this stuff on every thing that is exposed to corrision or galvanic reaction.

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Interesting. Hadn't thought of that. I've used it as a gasket sealer on steel-shim head gaskets, and on an Oldsmobile intake gasket that wouldn't stop leaking.

It's a crappy thread sealant, though.

Yep, it's pretty much the same thing (PTFE) as this stuff but, 1/10th, or more, the cost.

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Because 592 is an EXCELLENT thread sealer. Has essentially "Loctite thread-locker" blended-in, so it hardens rather than just solvent evaporation.

Expensive, and worth every penny. It's "ten times" as expensive as the brush-top "Teflon" (PTFE) tubs of thread sealer, but it works ten times as well.

 

[PlayingWithTBI]

Expensive, and worth every penny. It's "ten times" as expensive as the brush-top "Teflon" (PTFE) tubs of thread sealer, but it works ten times as well.

It works fine for me, if it works I don't need ten times good enough (you really don't need to yell at me. I can read and comprehend at a 5th grade or better level ). I use my stuff for everything including head bolts without any issues.

 

[evilunclegrimace]

It's a crappy thread sealant, though.

I am going to have to disagree here, 592 is anerobic, ie;it dries hard, 80632 stays pliable. I have used it for over 30 years and have not had a problem with it sealing.

 

[Scooterwrench]

He is dealing with blind holes,he doesn't need thread sealer he needs antiseize. The bronze colored aintiseize works best in my opinion.

 

[L31MaxExpress]

He is dealing with blind holes,he doesn't need thread sealer he needs antiseize. The bronze colored aintiseize works best in my opinion.

SBC thermostat bolts are not blind, atleast most of them are not.

 

[Scooterwrench]

All of them I've seen are. The holes in Smoky are blind holes,I've got a 305HO Q-jet manifold with blind holes. When did they start boring them all the way through?

 

[L31MaxExpress]

All of them I've seen are. The holes in Smoky are blind holes,I've got a 305HO Q-jet manifold with blind holes. When did they start boring them all the way through?

I have seen a bunch that are. I want to say my TPI manifold was. A lot of aftermarket manifolds are.