I have a pontiac grand am 1996 v6 with a 3.1L 3100 SFI engine. I have a coolant leak and I think it's coming from the water pump. When the car is cool and then turned on, about 4 to 9 minutes into warming up, coolant is hitting a belt and spraying out of the car's front end. When this is happening I see that there is coolant dripping off of the waterpump housing. The coolant started to spray everywhere about 15 seconds before the radiator fan kicked in. Why would this happen when first warming up only? Can a defective thermostat cause this to happen?
Mating surfaces of water pump slightly expand after warm up closing tighter on gasket in between, so the leak will not be as much. If you leave it, eventually it may get larger and will leak all the time. Change the water pump and/or it's gasket.
Stop guessing and have the cooling system pressure tested.
Understand what they do...thermostat is like a door inside the hose-either it is open or closed. Waterpump gasket is just a special paper that is between the pump and the engine block. The waterpump rotates so a shaft sticks out holding a pulley. Around that shaft has to be a material that does not wear very fast but allows shaft to rotate. It is called waterpump seal. Most likely that is gone so the waterpump is replaced with either a new one or a rebult one(depending on your finances). It lasted 15 years. Which is a good stretch, so you got to be expecting this kind of thing to happen.
