Thermostat housing bolt

The bottom bolt of the thermostat housing is stripped in the head. CRAP!!!
It's an '87 with 255000 on the odometer.
What is the best way to fix the problem?:helpme:

Drill the hole and tap new threads?
Drill the hole and use a helicoil insert?
JBWeld a stud in it?
Another solution that I haven't a clue about?

I ask because from looking in through the thermostat hole there doesn't appear to be alot of metal to drill into. I don't want to drill into the water jacket...that would be bad.:scared:

If you have room, and want to do it right, I'd go to the next bigger thread and tap it out. Or I'd try to cheat it with a JB weld stud. Good idea to stud instead of trying to bolt back into the JB. If you have to heli-coil, I'd use a solid insert like keen-sert instead of heli-coil wire type. You know what's going on, I don't think ther are any other options. Personally - JB weld.

JB weld not so much.I have had to drill the housing and thread in a larger stud .On some I was able to just thread in next size larger metric stud without tapping.Worth a try and for sure better than JB.

X2 on tapping with a metric tap the next larger size. I have done it in several places on mine and the have all held great so far.
After the larger tap, I would then insert a stud (instead of a bolt) with some lock-tight and let it setup before you put it back together. Just make sure you have enough clearance for the belt to not rub the stud.

If you drill oversize, you'll have to open up the hole in the housing flange as well.

A Heli-Coil is a workable solution, but be sure to apply some variety of sealant to the insert when you put it in (LocTite #545 Hydraulic Sealant - or equivalent - works well.) A Heli-Coil also has the advantage of being CRES, so it won't rust on you.

A threaded bushing is also an option - you can usually find them where you drill and tap a size or two up (3/8"-16 or 7/16"-14) and it restores the original thread. I don't know if they can be found in CRES as well, and the same caveat applies as for sealer.

It isn't a "blind" hole, which is why it ends up rusting and stripping on you (leave the coolant mix in too long, and corrosion becomes a factor.)

If it were me, I'd use the Heli-Coil, and replace the screw with either CRES or brass - if you absolutely have to use carbon steel (SAE5 or SAE8, or socket head,) make sure to coat the threads and shaft of the screw with RTV before you install it - both to seal the thread and to protect the screw from rusting again.

Whatever you do, I also highly suggest replacing the screws - they should both be threaded 5/16"-18, just different lengths.

LocTite/Permatex also makes a "thread forming" kit using something similar to JB-Weld, but I've not tried it yet and can't comment on it.

Thanks guys. I just wasn't sure on how much metal I had to work with on drilling it out. I don't like or want to do the JBWeld but wanted other opinions on it. I think I'll tap it out to the next larger size then put a stud in it with some locktite and sealer.