[soldermonkey]

After 14 years since the last thermostat change, the thermostat housing on my '74 Nova was leaking coolant. The mounting bolts were corroded and completely fused to the block and, inevitably, I broke off one of them. I successfully drilled out the remaining stud using a QuickCenter, but went too far with my 5/16" drill bit and accidentally poked a ~5/64" hole in the bottom of the mounting bolt cavity with the tip of the drill bit. I'm thinking I need to somehow plug this hole before reinstalling the thermostat housing, to prevent coolant from entering the bolt cavity. Any thoughts or advice would be greatly appreciated.

 

[the FLYER]

open a Photobucket account and follow the tutorial on posting images here at the site... get us an image or three and we'll see what we can do. the FB imaging doesn't work here i don't believe...

here's the tutorial...

http://www.stevesnovasite.com/forums/showthread.php?t=27716


welcome to the site


might try filling the hole with an epoxy sealer, just enough to fill opening but not prevent the bolt from being tightened or removed...

 

[soldermonkey]

Thanks for your prompt reply, and the tip about photobucket.com. Here a couple of photos:

Epoxy is a possibility, but I don't want it to crack or leak over time. Others have suggested blue RTV. I also though about tapping the hole at the bottom for a 6-32 screw, or maybe larger, then installing a screw with permanent Loctite. (There's quite a bit of room between the bottom of the thermostat housing mounting bolt and the bottom of the cavity.) I want to plug the hole, but also guard against have the plug come loose years later and cause a leak or, worse, break through the bottom of the cavity and get released into my block's cooling channels.

 

[bracketchev1221]

Ultra black RTV on the bolt threads and don't give it another thought. It's been used for years to seal head bolts that go into the water jacket.

 

[Dan_Lockwood]

On my 392 hemi half of the head bolts and half of the front timing cover bolts were open directly into the water jackets.

Like bracketchevy said, use bolt sealer and move on. You will not have any issues.

 

[my T mouse]

Rtv those threads or a gasket sealer, sold at local parts store. Make sure you allow plenty of time to dry

 

[soldermonkey]

In addition to sealing the bolt threads with RTV, do you think I should also cover the hole by filling in the bottom of the cavity with RTV?

 

[Dan_Lockwood]

In addition to sealing the bolt threads with RTV, do you think I should also cover the hole by filling in the bottom of the cavity with RTV?

No, the hole is in the same water cavity as the underside of the thermostat. It's all equal pressure and the same fluid.

 

[sbc1320]

You could run an allan head set screw down in it with some red lotite if you want, but like said RTV will do it just fine and also will stop the bolt from sticking next time..



PS: If the bolts seem to be really tight then take a hammer and rap the head of the bolt several times. Hit it pretty hard and lots of times this will shock the threads and release the bolt.

 

[65 Post]

Put some brown locktite gasket sealer on the threads and bolt it in. Ot get a stud a little longer than you need and install it. I put the loctite on my headbolts, they got to water, and have NEVER had a leak. It's only 15lbs pressure. You'll be fine. Dave

 

[Jim383]

I was gonna say silicone some studs in the holes and if they won't come out its a good thing,use some nylock nuts on top.

 

[MI-76]

I'd be tempted to pull the intake and bolt on a new one. "It's ruined," is a great excuse. I picked up my gently used performer for $50. Check your local Craigslist.

 

[soldermonkey]

I'm gonna go with RTV on the bolt. Thanks for all the good ideas. I'll let you all know how it turns out.

 

[soldermonkey]

FYI, RTV on the bolt did the trick just fine.

 

[the FLYER]

good to hear. :thumbsup: