Odd coolant leak

[inplansight]

My 87 tona has developed an odd coolant leak from the bleeder above the T-stat. The leak is small leaving just a coolant stain/ drops on top of the head, the threads inside the head are not in great shape but the plug will tighten up with no issues. I have tried liquid pipe thread sealant with no improvement, I might try Teflon tape the next time I am working on the car and see if there is an improvement.

What is the best way to fix this on the car, Core-cert, drill and tap for larger plug??

The car is not a DD and could be removed form service for a week or two but I like having a back up car and we all know what happens "while I am in there"....

Paul B

[135sohc]

Teflon tape worked for me. What size and configuration is the bleeder on your engine? (I have seen a couple different ones)

[inplansight]

Just a plug with a Allen hex 6MM, maybe.

[supercrackerbox]

Is it possible there's a hairline crack in the thermostat box?

[inplansight]

I would not rule out a cracked head as this engine has been in two different cars over the last 12 years, the engine has over 180K miles with out any major repairs. I have owned maybe 18 cars with the 2.2 engine and I have never seen one crack or leak coolant from this area.

Paul B

[bgbmxer]

Pressure test the system and see where it leaks from

[supercrackerbox]

I've seen them crack from the plugs being cranked down too tight. But at least it could be easily fixed if you want to take the head back off the car. Just weld the hole shut.

[inplansight]

This leak is both small and slow (4-5 days of driving required) also requires heat, pressure testing the cooling system has shown no leak.

Pressure test the system and see where it leaks from

Paul