Running hot 2002 pontaic aztec .......running hot. the radiator fans only come on if the heater is blasting inside the car. i have checked all relays and sensors. i have flushed radiator and replaced the ect sensor. why is my car running hot and why doesnt my radiator fans work when my motor gets hot

radiator fan may not be coming on make sure you can hear it running. Fan motor or relay is probably bad

Test both the cooling fan relay and the fuse (located under the hood and inside the control module box).

For the inop blower fan, test the switch if the fuse checks out.

The most common overlook thing is you got a air pocket, so before you go spend your money turn Heather on full blast, open the radiator cap, car running look for air bubbles, takes patience cause you got to wait for the thermostat to open up, you must refill the coolant really really slow snail pace, some car have a bleeding valve others have two chamber on the overflow bottle,good luck, if that doesn't work change the thermostat first and if that doesn't work I'm afraid you may need to replace water pump. . water pump

ENGINE NOT GOING TO START IF GET TOO HOT FIRST THING I WOULD REPLACE THERMOSTAT AND RADIATOR PRESSURE CAP THEN ADD COOLANT UNTIL COOLANT LEVEL CORRECT THATS WHEN THERMOSTAT OPEN UP AND TOP HOSE HOT.CHECK FOR LEAKING RADIATOR HOSES CHECK TOP RADIATOR HOSE CHECK BOTTOM RADIATOR HOSE.CHECK FOR LEAKS AROUND THE RADIATOR LOOK DOWN BELOW COOLANTS FANS CHECK FOR LEAKS AT RADIATOR CORES OR LEAKS AT THE RADIATOR PLASTIC SIDE CONTAINERS. CHECK FOR LEAKS AT WATER PUMP WEEP HOLE AND CHECK FOR LEAKS AT THE HEATER HOSES AROUND ENGINE BLOCK TO THE HEATER CORE HOSES. THERE IS A REASON CAR OVERHEAT.IF CAR OVERHEAT WHILE DRIVING YOU HAVE FAULTY THERMOSTAT OR LEAKING OUT COOLANT OR BLOWN HEAD GASKET.IF ENGINE OVER HEAT WHILE SITTING DURING A LONG IDLING PERIOD.YOU COULD HAVE FAULTY COOLANT TEMPERATURE SENSOR OR FAULTY COOLING FAN FUSE OR RELAY.HOT WIRE COOLANT TO SEE IF IT RUNS IF NO REPLACE FAN MOTOR. IF YES FAN MOTOR COULD HAVE FAULTY WIRE OR PCM FAILURE. CHECK ENGINE CRANKCASE IF OIL LOOKS LIKE MILK SHAKE ENGINE HEAD GASKET LEAKING.

will try to help.let car cool all the way off 1st take radiator cap off, top off w fluid, start car w/ radiator cap off. let it get to operating temperature w/motor running, keep addind fluid, look under car for leaks the whole time please!! if at any time-- you see fluid coming out beyond what you may spill or overfill,,shut the car off!! you may only be low on radiator coolant.with the radiator cap off while filling, you should see the fluid moving[circulating] inside the radiator, bubbles moving downward,,ok spewing upwards out of radiator NO if this repairs good, replace cap and drive 10miles regular speed. no hot,,good,,if hot let cool copletely,check cooling fan relays under hood,black box, look for fan relays, when key is moved back from on to off,,relayshould tick,put your finger on it while someone turns key off to on,WILL NOT SHOCK YOU!! just a very small vibration to fingertip. if this good, with engine running, do engine fan come on to cool, look between radiator and engine,at the fans to insure it;s coming on. you really should be able to hear it, but i prefer to see it visually. AS ALWAYS,IF YOU NEED FURTHER ASSISTANCE OR HAVE MORE QUESTIONS,PLEASE REPOST YOUR QUESTION, AND AN EXPERT WILL HELP WITH PHONE OR ONLINE ASSISTANCE.

Check the coolant temperature sensor (not the sender). Check that connection is clean and good. If you have electric radiator fans do they engage when car is hot. If nor check the fuse and the relay unit connections (under the front by the left inside fender). If you suspect the relay run a positive wire from the battery positive terminal directly to the fan. If the fan runs check the voltage to the relay and the voltage from it when triggered. If the relay is OK wiggle the wires on the coolant sender.

make sure you have radiator full of coolant
run the car to operating temperature
check the operation of the cooling fan
feel the upper radiator hose and the lower radiator hose. they both should be hot.
if one is cold then you may have a bad thermostat or restricted flow
if cooling fan does not come on when engine is hot then you have bad cooling fan switch, relay or motor.
good luck

Their is a sensor screwed into the radiator which sends a signal to the fan relay when the radiator gets hot and activates the fan. If you changed the relay then this is most likely the problem. But it may be the fan. To check remove the plug from the fan and when radiator get's hot check if power is comming through the wire's.

Radiator Fan Control Relay Switch. I bet your electric fan doesn't run?

Sounds like Clutch in your fan

The coolant level is right on, no hoses are leaking and the accessory belt is intact. You start the engine, let it idle and make a visual inspection. There's no sign of belt slippage.
If your car is like most, the cooling fan is mounted to its drive pulley via a clutch. Clutch fans operate at different speeds under different conditions to help reduce drain on the engine and to save fuel. When the engine is hot, the clutch fan runs nearly as fast as the engine. When the engine is cold, the fan runs much more slowly.
The fan clutch operation is regulated by a valve that is opened and closed by a thermostatic spring. The valve controls the flow of a viscous silicone fluid between chambers in the clutch assembly. When the engine is cold, the clutch is essentially disengaged, which is why the fan runs at its slowest compared to the engine's speed. As the engine warms up, the air flowing to the fan assembly becomes hotter. The hotter air causes the thermostatic spring to unwind and open the valve. Silicone fluid from the reservoir chamber flows into the main chamber, engaging the clutch, and the fan spins faster (though it's still slightly slower than the engine.

Hope this helps!