Block Coolant Leak Repair???

[SeattleCarGuy]

Have an old 396 Chevrolet. Coolant plug above #3 cylinder where temp sending unit goes was rusted stuck and stripped. Used heat, broke an Eazy-Out, etc. trying to get the plug out. In so drilling, we got too close to the edge and removed some metal where the threads are so in installing the Temp Sending Unit, there is a gap between the sender and the threads which we filled with JB Weld. Well, it leaks letting some coolant seep out.

Next step is to remove the cylinder head and take it to machine shop for welding and install of helicoil.

Any other suggestions to save tearing the motor down? Any coolant sealer products out there that might work?

Thank you,

Paul

[L78steve]

If its not a gaping hole try some Bars leak.

[PapaSmurf]

Paul
Be careful with the BarsLeak. It will plug up small leaks temporarily but will also plug up your radiator & potentially cause heating issues.

[Lynn]

I wouldn't use any sealing product on it.
Fix it right, fix it once.

[Mr.Nickey Nova]

GM sells a product called (Cooling System Seal Tabs) part# 12378254. Used it in my 05 pickup when i had a little coolant leak, couldn't tell where it was coming from,possible head gasket. Worked like a charm and that was five years ago.It's made out of some kind of vegetable formula that seals minor leaks. You can get it at your local Chevrolet dealer, give it a try...

[bugsy]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lynn</div><div class="ubbcode-body">I wouldn't use any sealing product on it.
Fix it right, fix it once. </div></div> X1000 take the head off and fix it right. JMO

[PxTx]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Mr.Nickey Nova</div><div class="ubbcode-body">GM sells a product called (Cooling System Seal Tabs) part# 12378254. Used it in my 05 pickup when i had a little coolant leak, couldn't tell where it was coming from,possible head gasket. Worked like a charm and that was five years ago.It's made out of some kind of vegetable formula that seals minor leaks. You can get it at your local Chevrolet dealer, give it a try... </div></div>

Those tabs kept many a Cadillac HT4100 alive throughout the 1980's. Aluminum block and iron heads! Not sure there was a &quot;right fix&quot; for many of that engine's shortcomings other than using those tabs. My Dad was a Caddy mechanic for 30 years and I have seen more success than failures with them. I wouldn't be afraid of using 'em.

[Lynn]

Yeah, forgot about the tabs, and I used to work at a GM dealer. IIRC, they are triggered by oxygen, so at least in THEORY, they don't plug up heater cores and radiators. Still.... If I had a small leak and didn't know where it was coming from, I would use the GM tabs.
But if I had a leak, and knew the source and how to fix it, I would fix it. Why take a chance plugging up something else?

[Billohio]

I used a locktite thread repair product recently that worked well. put it in hole, a coating on the sender and screw it in. I will save the hole and new threads if you don't want to disassemble. At least it's supposed to! Worked on what I did.

[Mk IV Muscle]

The best answer would be to pull the head, IMO. If this isn't an option then I too would use the GM tablets. Also have heard that Irontite works very well, but have no personal experience with it.

Good luck with whatever method you choose.