Hi guys, my 97 civic ex has a coolant leak coming from the engine block where the upper radiator hose connects. It also has a problem where the reservoir tank overflows. Prior to using K&W Permanent Block seal, since i thought i had a bad head gasket, the reservoir would be empty in 1-2 weeks. After using the block seal, the reservoir tank seems to be overflowing with coolant. I have not had any problems with overheating since the temperature gauge stays constant below the middle mark. Does anyone know how to fix these problems? Thank you. Here are some pictures

 

First are you simply overfilling it? The tank should only be about 1/3 full with the engine cold. Also with the engine cold, take off the radiator cap and confirm the radiator is full to the top.

If it's not that, there is probably some head gasket leakage pushing the coolant into the tank. This can result in overheating if there is enough of a bubble formed in the engine.

The leak at the fitting should be fixable by unbolting it from the engine, clean both surfaces down to bare metal, and re-attach with Hondabond or other silicone sealer. I don't think there is an official gasket for this part.

 

I'm not overfilling it. I would usually fill the reservoir to minimum mark and after some time driving, it will overflow. Radiator is not full to the top when engine is cold. It probably is a head gasket leak. Is it recommended to use a different head gasket seal since i already used K&W Permanent Block Seal? Also, i'm going to purchase a radiator cap at autozone if it is the problem.

 

Pull the head, have it checked/machined and reinstall with new head gasket.

Fix leak as mentioned. 94

 

Stop-leak is never recommended. Replace the gasket.