Car started overheating two days ago and has happened every day since not sure whats wrong. Only happens on my way home from work when it was hot. Fans go off I hear them, it only starts overheating when at a redlight, but when i start driving again the temp drops. When I am done driving the I hear the radiator boiling. I have water in the radiator instead of anti-freeze (moneys tight haha) I think I just need to put antifreeze so it doesn't get boiling hot in the sun. Anyone got any other ideas?

 

A gallon of Prestone 50/50 at Walmart is I think $15 or so and is more than enough coolant for you. A bottle of Water Wetter is about $8.99 at Autozone.

Check under the car for coolant leaks. At a red light rev the engine in neutral to about 3k while putting your HVAC temp control to full heat. If temp gauge goes down it could mean you need a new water pump.

 

Water pump could be going. How many miles on the car? You sure you hear the fan on? Had the same problem and it turned out to be a loose fan wire.

 

My cars a 98 it has 150K miles on it. Im almost positive I hear them. I'll check again though. Radiator and Thermostat are both brand new. It's not leaking water that's why I was hesistant to jump to the water pump being out.

 

Is the fan pushed right up on the rad w/o any space between it?

Bleed the cooling system with the front of the car higher then the rear.. rev it a little with heat on full blast. squeeze hoses to help evac air pockets.

 

Have you ever had the timing belt/water pump done? If not, you should probably do that. Would eliminate the risk of the timing belt breaking + you would see if the water pump is bad.

 

if your fan turns and you have your a new thermostat and still nothing I would try the thermoswitch which is on the thermostat housing. I changed everything else like you and was still overheating. then I changed the thermoswitch and it never got hot again

 

Thats the fan switch......