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Username Post: Help! Thermostat Housing Mounting Stud loose.        (Topic#359761)
ampico-kid 
Contributor
Posts: 106

Reg: 07-12-17
02-09-20 11:39 AM - Post#2786180    

My '63 Impala SS w/327 had a small coolant leak by the thermostat housing. It was the housing itself which was all pitted and potholed where the hose attached. I bought a NOS and prepped it to replace the original. When I went to install the new one I found that one of the two mounting studs wouldn't tighten. I removed the housing and the stud easily loosened and came up out of the threaded hole in the manifold. I removed the good stud to compare and found that the bad one was about 1/4" shorter than the good side. The stud had obviously been replaced at some point with a shorter version. I checked the depth of the two holes and that was case. I'm assuming that about a 1/4" piece of the original bad stud is still in the hole.

The question is....what do I do now? I'd rather not have to pull the intake manifold. Could I retap to a slightly larger stud? Use some kind of a hardening epoxy to anchor the stud in the hole? Is there something that will harden enough to hold the stud in place? Or should I ?? Never had to deal with this kind of a situation before...any advice would be greatly appreciated. Thanks. Bob



 


Verne_Frantz 
Member #574 "61-64 Subject Matter Expert"
Posts: 5699
Verne_Frantz
Loc: Hightstown,NJ USA
Reg: 08-22-00
02-09-20 12:33 PM - Post#2786185    
    In response to ampico-kid

Buy a Helicoil kit for a 3/8-16 thread and follow the instructions. The housing should be held down by bolts, not studs and nuts.

Verne



 
ampico-kid 
Contributor
Posts: 106

Reg: 07-12-17
02-09-20 01:27 PM - Post#2786189    
    In response to Verne_Frantz

  • Verne_Frantz Said:
Buy a Helicoil kit for a 3/8-16 thread and follow the instructions. The housing should be held down by bolts, not studs and nuts.

Verne


Thanks Verne....it pays to ask questions in the right place. I had no idea such a thing as the Helicoil even existed. You learn something new every day. Thanks again. Bob



 
ampico-kid 
Contributor
Posts: 106

Reg: 07-12-17
02-09-20 02:23 PM - Post#2786195    
    In response to Verne_Frantz

  • Verne_Frantz Said:
Buy a Helicoil kit for a 3/8-16 thread and follow the instructions. The housing should be held down by bolts, not studs and nuts.

Verne



The bolts should be 3/8-16 thread. I assume they would each have a lock washer. What length are the bolts? Thanks again. Bob



 
Verne_Frantz 
Member #574 "61-64 Subject Matter Expert"
Posts: 5699
Verne_Frantz
Loc: Hightstown,NJ USA
Reg: 08-22-00
02-09-20 06:18 PM - Post#2786206    
    In response to ampico-kid

No lock washers. I believe the bolts are about 1-1/2", but I'd have to wait until tomorrow to measure one.

Verne



 
DonSSDD 
Silver Supporting Member
Posts: 7255
DonSSDD
Loc: Nova Scotia, Canada
Reg: 08-21-01
02-10-20 05:28 AM - Post#2786219    
    In response to Verne_Frantz

I’d buy helicoil brand as well, some of the off brand ones are not as strong.

63 Pontiac Parisienne Sport Coupe(CDN Chev mechanically (409, 4 speed),62 Bel Air SC (sold), 59 El Camino (sold), 62 Bel Air SC(sold), 63 SWC Vette (sold),
Member #2194


 
ampico-kid 
Contributor
Posts: 106

Reg: 07-12-17
02-10-20 08:59 AM - Post#2786230    
    In response to DonSSDD

  • DonSSDD Said:
I’d buy helicoil brand as well, some of the off brand ones are not as strong.




OK..thanks for the heads up. I'll make sure it's a Helicoil brand.



 
Verne_Frantz 
Member #574 "61-64 Subject Matter Expert"
Posts: 5699
Verne_Frantz
Loc: Hightstown,NJ USA
Reg: 08-22-00
02-10-20 09:04 AM - Post#2786232    
    In response to ampico-kid

I checked an original bolt and they are 1", not 1-1/2". Standard hex head. Originals have various head markings but "UR" is very common.

Verne

Just to be perfectly clear in case you're not used to normal bolt measurements, the length is the length of the threads, not the overall length. In the case of a bolt with a shoulder, it's measured from under the head to the end.



Edited by Verne_Frantz on 02-10-20 09:08 AM. Reason for edit: No reason given.

 
turbo38s10 
"9th Year" Gold Supporting Member
Posts: 1725
turbo38s10
Loc: Agawam,MA
Reg: 09-17-09
02-10-20 10:11 AM - Post#2786234    
    In response to Verne_Frantz

Here is a good video on inserts. A little long but interesting. Seems Bigserts win out.
https://www.threadkits.com/big-sert/
https://www.youtube.com/watch?v=LpDduCVUy6w



Edited by turbo38s10 on 02-10-20 10:15 AM. Reason for edit: No reason given.

 
ampico-kid 
Contributor
Posts: 106

Reg: 07-12-17
02-10-20 02:46 PM - Post#2786250    
    In response to Verne_Frantz

  • Verne_Frantz Said:
I checked an original bolt and they are 1", not 1-1/2". Standard hex head. Originals have various head markings but "UR" is very common.

Verne

Just to be perfectly clear in case you're not used to normal bolt measurements, the length is the length of the threads, not the overall length. In the case of a bolt with a shoulder, it's measured from under the head to the end.



Thanks Verne....I understand. The only complication is that one of the holes was pretty badly mangled. Looks like someone may have tried to dig out the old bolt that was in there and replace it with the stud. One of the holes drilled out and threaded great. The other mangled one...not so sure. I've put some locktite on the threads before screwing the Helicoil sleeve into it. It seemed to screw in alright. I'm going to give it some time to cure before trying to tighten up the bolts. I may give it a shot tomorrow. I'll let you know how I make out. Thanks for all of your help. Bob



 
ampico-kid 
Contributor
Posts: 106

Reg: 07-12-17
02-10-20 02:47 PM - Post#2786251    
    In response to turbo38s10

Thanks...already checked out some YouTube videos. Very informative.....



 
Verne_Frantz 
Member #574 "61-64 Subject Matter Expert"
Posts: 5699
Verne_Frantz
Loc: Hightstown,NJ USA
Reg: 08-22-00
02-10-20 07:32 PM - Post#2786273    
    In response to ampico-kid

I hope it works out for you. Those bolts don't have to be very tight as long as you have some good gasket sealer on both sides of the gasket (NOT RTV).
If you can torque the one to 15 ft lbs, it should be fine.

Verne



 
ampico-kid 
Contributor
Posts: 106

Reg: 07-12-17
02-11-20 07:03 AM - Post#2786292    
    In response to Verne_Frantz

What's the finish on the bolts? Engine orange or natural?



 
Verne_Frantz 
Member #574 "61-64 Subject Matter Expert"
Posts: 5699
Verne_Frantz
Loc: Hightstown,NJ USA
Reg: 08-22-00
02-11-20 08:23 AM - Post#2786298    
    In response to ampico-kid

Originally they would have had a dull zinc finish.
Verne



 
ampico-kid 
Contributor
Posts: 106

Reg: 07-12-17
02-12-20 12:58 PM - Post#2786382    
    In response to Verne_Frantz

I wanted to clue you all in to the final outcome. I used the Helicoil insert to repair the damaged/rusted threads on my thermostat housing. I was very concerned because one of the holes was badly mangled and the drill seemed like it was all over the place. The Helicoil went in easy enough, and possibly a little too easy I thought, so I covered it with gel type locktite, inserted it, and let it cure for a few days. I reassembled it today and torqued it to about 15 ft.lbs. and all is well. I ran the engine up to operating temperature and no leaks, no surprises, so apparently all is well. Thanks Verne for the helpful tips and advice. It's much appreciated. Bob



 
Verne_Frantz 
Member #574 "61-64 Subject Matter Expert"
Posts: 5699
Verne_Frantz
Loc: Hightstown,NJ USA
Reg: 08-22-00
02-12-20 02:25 PM - Post#2786387    
    In response to ampico-kid

Glad to hear it worked out!

Verne



 
junky 
Valued Contributor
Posts: 3228

Loc: Northeast CT
Reg: 06-27-10
02-12-20 08:12 PM - Post#2786398    
    In response to ampico-kid

Keep an eye on it when the engine gets hot, because Locktite is released with heat, depending on which one you used. They make a Locktite that is specifically for loose threads.

Never argue with an idiot. He'll drag you down to his level, then beat you with experience.


 
ampico-kid 
Contributor
Posts: 106

Reg: 07-12-17
02-13-20 08:53 AM - Post#2786419    
    In response to junky

  • junky Said:
Keep an eye on it when the engine gets hot, because Locktite is released with heat, depending on which one you used. They make a Locktite that is specifically for loose threads.



The formula I used indicates that it has a temperature resistance range of -65F to +300F. I hope my intake manifold/thermostat housing never sees 300 degrees F. Thanks for the heads up though, I'll keep an eye on it.



 


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