I have noticed that after I shut off my 96 accord, I can hear a fan running. When I pop the hood, I notice that one of the two fans still runs for a few seconds, then shuts off. It is not consistent, however, it does happen more often than before

What is making one fan run after the car shuts off??

any help in this matter is greatly appreciated!!

 

There are two coolant temperature sensors on your car, A and B. Sensor A will turn on the fans when the engine is running when the temperature reaches some set level.

Sensor B will turn on the fans when the car is shut off if the coolant is above a certain temperature (it is higher than sensor A). That is what you are noticing.

I would make sure the radiator is full of coolant and the overflow bottle. Check when the engine is cold. Also, check the fins of the radiator for deterioration. You may want to lightly spray water on the radiator fins to clean out any bugs/dirt to help the radiator cool better.

 

I looked at the fan, no deterioration, the radiator is new (a few months old) and the reservoir and radiator is filled.....

 

Perhaps thermoswitch B which controls on/off of the fans w/ keyswitch Off has drifted and is coming on at slightly lower temp than before.

Also the thermostat may drift and cause engine to run warmer than normal, contributing to engine-off fans running.

The new radiator may not be quite as efficient as OEM radiator causing temps to run a little higher.

When engine is shut down after running at highway speed for a while, the coolant trapped in the engine warms well above 200F. This heating can damage the head gasket. Honda added the engine-off fans to reduce this "heat soak" overheating issue and protect the head gasket.

good luck

 

I would unplug thermo switch B and clean out any crud on it using electrical cleaner. It located under the distributor closer to the front of the car and has a green plug with two wires going to it.

 

I thought fan-switch B is in the nozzle for the upper radiator hose. The one under the distributor is the temperature sensor for the ECU.

 

Yes, Jim is correct that Thermoswitch B is on the upper radiator hose fitting at the engine side.

good luck

 

I'm sure this is implied or assumed....but as stated by Texas. The fan running after the car is shut off is by design. So yes need to check to be sure everything is ok-coolant level, "crud" on the connector, ect....but if it is running and shutting off...it is just hot. Not sure which part of the world you are in so if the outside temp is still warm and or after a long drive and this happening, don't get too worried if everything else checks out.

 

I live in Charleston, SC. I wonder if the thermostat needs to be replaced. I have had this car for about 5 years. Since there wasnt any detailed paperwork as far a service is concerned, if didnt do it, then it was never done. I have never replaced the thermostat. Also, I noticed a small coolant fluid puddle (size of quarter) under my car as I went to change the oil. I cant tell where it is coming from, I just see it dripping off of the oil pan....

Clearly all these things may be connected....just dont know how.

any ideas????