By January 24, 2012 Read More →

Car Overheating – New Thermostat and Water Pump

My car keeps overheating. My husband has changed the thermostat, water pump, and head gasket. We have even pump the radiator hose that goes to the engine from radiator to make sure air bubbles are out. We thought it was fixed till today it overheated again. Only this time there is still water in the reservoir.

Can you give us some advice on what to do next?


Hi there,

First thing’s first, get a cooling system pressure test to determine if you have an internal or external coolant leak. Looking at the coolant level inside the overflow bottle does not tell you what is happening inside the radiator.  The radiator could be low or empty and the overflow could still have some coolant, so you have to check inside the radiator.  I would not be surprised if the radiator on a 11 year old vehicle is restricted with rust and calcium deposits at the bottom which you can not see or “flush out”. If the coolant cant flow through the radiator the engine will overheat. If the top radiator hose is hot and the bottom hose is cold when the engine is overheating, you might have a radiator restriction, an air pocket in the system or the electric cooling fan is not coming on.

Second, check the electric cooling fan motor operation, the fan up near the radiator should cycle on and off as the engine heats up.  if you just have 1 electric fan near the radiator that should also come on when the A/C compressor is turned on, so if it does not come on with the a/c on…the fan motor is probably bad.

If you have 2 electric fans, one is for the A/C and the other for the radiator so my test really wont tell you much.  the electric cooling fan is required to come on when at stops or slow speeds, but not so much at freeway speeds. So if the overheating is happening when the car is at a stop light or at idle and the fan is not coming on…the fan needs to be checked. There is a sensor for the fan at the bottom of the radiator that should also be checked to make sure it is sending the signal to the fan motor.

Lastly, when the engine is overheating, turn on the heater. If the air coming out of the vents is hot, then you have enough coolant inside the engine to operate the heater and might indicate a problem with the electric cooling fan, or a restriction in the radiator. If you do not have hot air coming out the vents, then you most likely have no coolant in the system….due to a leak somewhere or a radiator that is so restricted that no coolant is allowing to flow inside the engine.

Hope this helps

Austin Davis


Follow up question

Thank you  for your reply , However, when the car over heats it blows cold air through the vents. We checked the fan it also works. so were at a loss when it comes to the overheating.


Follow up reply

Cold air means NO hot coolant in the engine…..its all leaked out, or is not circulating.  Pressure test first, then look very hard at the radiator for a restriction or an air pocket not allowing the coolant to circulate. New thermostat should have been 195 degrees.

Austin Davis

Posted in: Over Heating

About the Author:

Austin Davis, consumer car repair advocate. "Hi there! I love to help people solve their car repair problems and I hope my site was helpful to you today. Thank you for stopping by."

Comments are closed.