88 cougar has a coolant leak. it only leaks on real cold
nights without the car even been running for days. i fill it
up, start it and look for leaks when its running and no leaks.
not a lot, just a puddle or two. could this be related to my
service light being on?
Sometimes a water pump shaft seal will leak a little when
cold, then seal up when heated, or the leakage is small
enough to evaporate when the engine is running. If this
happens, a dose of water pump lube/seal additive in the
radiator may slow down the leak, but eventually the leak
will increase and the water pump will need to be replaced.
You could try radiator stop-leak, but it is not as effective
on the dynamic seal in the water pump as it is on fixed
gasket seals, and it may reduce cooling performance.
A leaking water pump will not activate any service light.