My 96 Galant S is constantly losing coolant, i.e., I keep on refilling the radiator with about half a quart every 4-5 days. I do not see any leak when the car is parked overnight. Even when I drive it for a while and pull over while the engine is still running, I do not see any leak. Any idea why this is happening? Thanks in advance for any help.
Three main possibilities: the radiator cap is leaking under pressure, or there's a pin hole in one of the hoses, or there's a hole in the radiator.
You don't mention rough running or white exhaust smoke, so a failing head gasket is unlikely.
You also don't mention any coolant smell in the cabin, so the heater core is not leaking.
When cold, pull the rad cap off and look at the coolant. Is there an oily film or grey-white goo? If so there's oil in the water, and the head gasket has failed.
Does the rad cap rubber seal look damaged or cracked? If so, replace it.
Squeeze all the hoses: they should be firm, not hard or soft and squishy. If not firm, have them replaced. Look at the 1" hoses that connect the engine to the heater, through the firewall. There's also some small hoses that connect part of the heater system to the main coolant hoses (rear of the engine). If these are contaminated with oil, or soft and squishy, replace them.
If the engine side of the rad is corroding away, its time for a new radiator, with all new hoses.
Lastly, look at the overflow bottle. There's a gasket under the lid. Is this sealing correctly? This is not essential, as the main sealing is done by the radiator cap.
Stewart DIBBS
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.