My 1995 Pontiac Grand Prix SE 3.1 is losing coolant, but it has some symptoms and not others?

i would guess the intake gaskets and maybe the waterpump are leaking. when is it low on coolant it will overheat, erractic temp gauge readings, and the heater core will have air in it instead of coolant and blow cold air

You have very little anti freeze left in the system and are overheating your motor. 3.1's are known for intake manifold coolant leaks and are very common. It sounds like you also have a bad water pump seal which seals the pulley shaft. The reason you don't get an accurate temperature reading is because there is no coolant where the temperature sending unit is, there is only an air pocket with steam. You keep driving it that way and revving the motor you will end up with warped cylinder heads or a seized motor.

The only way you get the "milkshake oil" is when there is coolant leaking into the oil from a blown head gasket, you're leaking down the side of the motor, not into it.

Fix the problems before you end up walking!

You got a leaking head gasket.This accounts for the loss of coolant and no you don't have to have milky oil to have a blown or leaking head gasket if you are leaking coolant into the cylinder. This would also account for the no heat if there is air in the coolant system or the coolant was low and not getting to the heater core. The blown head gasket could be from a bad water pump this could account for the water leaking around the pump and the other problems.

The steam coming from "somewhere near the water pump" is probably from the water pump it self. Sounds like the seal is going out in the pump. When the seal is bad you'll get water and/or steam coming out around the pump shaft. With a poorly working pump you'll also get that heater problem. As to the leak at the rear it could be a freeze plug or an intake gasket.

the final transmission may well be a alternative for the single that exchange into orginully interior the motor vehicle. there have been 2 transmissions available with the 4 cylindar whether: the three speed motor vehicle which you have, and a 5 speed instruction manual. you are able to replace it with a 5 speed in case you want, it would be high priced enhancing the underhood to settle for the instruction manual as a exchange of the motor vehicle, aswell as a results of fact the interior for the kit shift. or you are able to bypass with the three speed motor vehicle. whether it would be ultimate to bypass with a alternative motor vehicle for what you have, as a results of fact the ECM is already programmed for the computerized transmission.

^^^ reving

intake manifold gasket is leaking, common problem, have it replaced and you will be fine

good luck

Your thermostat is froze.

Among other things!