When driving, I notice that my thermostat fluctuates, but doesn't overheat. When I shut my car off, I can hear the fan under the hood still running. It will shut off after a few seconds, however, it comes back on for a few more seconds, then shuts off. I have checked my coolant, radiator, fans....no damage or anything....

I got this car about five years ago, and of all the things I replaced, the thermostat wasn't something that got changed..

any ideas as to why the fan keeps running after the car shuts off

 

How much fluxuation in the temp. gauge are you getting?

There are 4 sensors dealing with coolant temperature on your car.

There are two coolant temperature switch (A & B) that control the fans on your car, that are on/off switches. Switch A turns on when the coolant reaches a set temperature while the car is running. Switch B does the same thing, but is in control when the engine is not running.

The third switch is the coolant temperature is what the engine computer uses for fuel/air ratio, etc. It sends a range of temps. Fourth, the temperature sending unit is what your gauge in the car uses to move the needle.

The thermostat just adjusts the rate of coolant flow through the car based on the coolant temperature. If both hoses coming from the radiator are hot, then your thermostat is probably ok. If you decide to drain the coolant system, I would replace with a thermostat from the dealership.

With that said, I would inspect the cooling system. When the engine is cold, remove the radiator cap and see if the radiator is filled to the top with coolant. If not, fill it up with a 50:50 mix. Also inspect the fins of the radiator for deterioration. Right before mine gave out, the aluminum fins were coming like on ribbon.

Also, start the car and turn on the a/c. Do both fans at the radiator turn on?

 

Sometimes its in the middle, the it elevates slightly, then it drops below the halfway mark...the cycle repeats itself..

Will check the radiator and hoses in the morning...

 

I checked my hoses this morning. The upper hose is hot to the touch after driving for approx. 20 mins. The lower hose is almost warm, I was able to touch and hold the hose. The radiator is full and the reservoir has coolant in it as well.....

Is the lower hose being lukewarm normal????

 

I would get a new thermostat from the dealership and install it. Plan on changing your coolant as well.

 

While you're at it, try to take a look inside the radiator to see if it has scaly crusty deposits. When it's drained that's a good opportunity to flush the cooling system with some kind of cleaner/flush to clean up the scale.

 

I just picked up the thermostat from the dealership. I will get my coolant flushed as well. I will keep you posted on the outcome..


Thank you!!!!

I absolutely LOVE this site!!!

 

I changed the thermostat and flushed coolant....so far...so good.

thanks again everyone for such quick response and help...