99 Grand Am Overheating
Causeless
05-28-2007, 09:43 PM
New to the forum but thought I would see if I could get some help. I have a 99 Grand Am GT. At idle it runs about 200 degeres but as soon as I start down the road it begins to overheat and fast! The radiator and thermostat have been replaced recently and the water pump is under a year old. Also the heat isn't warm after 20 mins of idle when the temp is already at 200. No noticable water in the oil.. Suggestions?:banghead:
GTP Dad
05-29-2007, 11:16 AM
Welcome to AF!!
I suggest you check the radiator as it sounds like the radiator may be blocked or you have air in the system. Air would be the reason that the temp rises quickly but the heat takes time to get warm. I suggest if you have a radiator cap that you open the cap and start the car. It helps if you point the nose of the car uphill. Allow the car to warm up and you should see the level of the water drop once the thermostat opens. If it drops then refill and repeat several times. If you don't have a radiator cap but one on the reservoir you will need to open the vents on the top of the thermostat housing or on the block to allow the air out. You will need to repeat this several times as well to get all the air out of the system.
I suggest you check the radiator as it sounds like the radiator may be blocked or you have air in the system. Air would be the reason that the temp rises quickly but the heat takes time to get warm. I suggest if you have a radiator cap that you open the cap and start the car. It helps if you point the nose of the car uphill. Allow the car to warm up and you should see the level of the water drop once the thermostat opens. If it drops then refill and repeat several times. If you don't have a radiator cap but one on the reservoir you will need to open the vents on the top of the thermostat housing or on the block to allow the air out. You will need to repeat this several times as well to get all the air out of the system.
Automotive Network, Inc., Copyright ©2026