I recently replaced a leaking valley pan gasket a couple months ago. All is well until now I notice a coolant smell from the engine after a long trip. Sure enough head gaskets are leaking externally at the rear of the engine. I am tempted to try a stop leak product since this a slow leak but don't want to clog my radiator as I just had it rodded out. What do you think?

 

Do you think it leaked as a result of something you did while changing the valley pan gasket or just coincidence?

 

Stay away from the stop leak products unless you want even more problems.

 

stay away from stop leak. Just continue to watch temperature and fill coolant. Not ALL headgasket failures cause overheating.

 

Probably just coincidence. I was going to add half a tube of alumaseal to see if it would help. It is not overheating now, I just have to watch the coolant level. This is an external leak as far as I know b/c my block tester detected no gases and it is running fine. Anybody used a tablespoon of black pepper?

 

I really wouldn't use ANY LEAK STOP.

 

Probably will not use a "stop leak." Did some research and GM apparently added "coolant tabs" to vehicles to prevent leak with no adverse side effects.