Okay so i took the weekend and got a new cylinder head from the JY, rebuilt it, and put everything back together only to discover a coolant leak from the bottom hole of the thermostat cover. Pulled it back a part and found a piece of the cast metal sitting inside here and coolant running out of the bottom bolt hole in the head from the inside. What happened is the metal rusted away on the inside and caused a hole to form where the bolt threads into. I know the pictures are kinda crappy but it gets the idea. I am looking for ideas how to go about fixing this without removing the head again? Any help is appreciated. thank you.

I wondered about super prepping the area and JB welding and then re-tapping it the same size? Not sure if that would hold up to the coolant?

 

I have an idea but, I'm not sure if it's possible with the head still on the vehicle. I don't think I'd trust JB weld but, sealing up the leak with a wire welder, then retapping the hole sounds good to me.

 

That may be possible with it still on the car, the hole is pretty big and with the right angle I could get to it. But I wonder about it being cast if it would cause other issues? I would just need to stuff some rags inside to make sure no flash can get anywhere else

My other thought was soldering the hole shut with plumbing solder?

 

I'd use the same sealer on those bolt threads as the factory recommends for #11 head bolt. Same thing, really.

 

^^^This is what I did when I had the same problem with my 95 and it never leaked after. Hope it works for you too.

 

Permatex or Indian shellac on the bolt threads is all you need.

 

so your saying just thread sealant (definately have that on hand since i just swapped heads) and not worry about trying repair the hole? I can give that a shot, heck whats the worst that can happen!

I'll definately let it sit 24 hours before even thinking about starting it!

is the shellac going to set up too hard and make it unserviceable in the future? I have never used it so its new to me; have seen it in the stores plenty though.

 

The same stuff you're supposed to use on #11 head bolt. Think about it.

You did use something on #11, didn't you? LocTite 592 or equivalent. I use #2 Permatex FWIW.

 

definately used thread sealant on number 11, no doubts about that. I think it was the 59214, high temp thread sealant. Couldn't find the sealant that the manual states, but did a little research and the common consensus was that it was an acceptable substitute.

BTW off subject but thanks cruiser for the 88 mj electircal manual, came in handy yesterday when swapping over a harness from a 90 into the 89. Just a good guide to see where everything went since they changed a plug or two in between 89-90 (mainly the 4 & 6 terminal plug by the relays)

 

Use it on the thermostat bolt threads then. May I suggest that while you're there now, go buy a 83501426 factory stat from the dealer?

 

i would really like to but there is one in town here (all of indy), it is at the dealership where i live , but they want 35 bucks for it! I tried my best to talk them down and they just won't come off of it!

 

Geez. Highway robbery.

 

Tell me about it, its rediculous! it would make you think its made of gold for that matter!

so looks as if the common consensus is that the thread sealant should be sufficient to seal that up so no more leaky leaky? opposed to the indian shellac

 

Yes. I like Indian Head shellac but not sure it's best for this purpose.

 

Indian head shellac should work fine. #11 head bolt is a different application because of its close proximity to an exhaust port.