The electric radiator fan runs after truck is shut off. Will turn off after 30-40 min. Is this normal?

If they're electric fans, that's normal as the fans are cooling the radiator down. If you're still worried about it, the take your car to a radiator specialist or your mechanic.

Many cars have this feature. The fan will run for a few minutes at a time until the coolant in the radiator drops below a certain temperature. Most vehicles with this feature will have a warning label on the radiator shroud indicating that the fan may start without warning when the engine or radiator is still hot. The only time you would need to be concerned would be if the fan continues to run without turning itself off, and causing the battery to be drained.

idle learn procedure:

turn off all electrical items (AC fan, audio, lights, defogger, etc.)
Start the engine and hold it at 3,000 rpm with no load (in park or Neutral) until the radiator fan comes on or the engine coolant gauge shows normal running temp.

Now let the engine idle for a minimum of 5 mins with no electrical loads. If the radiator fan cycles on during this time, you must add the fan running time to the 5 mins.

SOUND LIKE FAULTY CLUTCH FAN OR THE AUXILIARY ELECTRIC COOLANT FAN NOT RUNNING. CHECK AUXILIARY FAN FUSE AND RELAY. IF LOOK GOOD HOT WIRE TO SEE IF FAN TURNS ON IF NOT FAN FAULTY. IF FAN RUNS YOU HAVE FAULTY THERMO SWITCH. WHICH LOCATED AT THE BOTTOM OF RADIATOR ON THE LEFT HAND SIDE OR ON THE LOWER RADIATOR HOSE ON THE RIGHT HAND SIDE OF THE ENGINE COMPARTMENT.IF FANS OKAY COOLANT LEVEL CORRECT.REPLACE THERMOSTAT.HAVE RADIATOR AND ENGINE FLUSHED.CHECK IN FRONT OF GRILLE MAKE SURE NO DEBRIS BLOCKING OFF AIR FLOW THROUGH RADIATOR CORES AND AC CONDENSOR CORES.

Your English is very good.

From what you have described, which is a rapid over heating of the radiator coolant fluid and therefore a hot engine condition, it would appear that the thermostat in the engine's cooling system is faulty.

If the thermostat is sticking in the closed or nearly closed position temporarily, there will be no flow or very little coolant flow between the engine and the radiator and the engine will overheat.

You have advised that after the engine is shut off , and radiator coolant fluid has cooled, you re-start the engine and drive the car without the overheating condition occurring again and the radiator coolant temperature is normal. This time there is no overheating because the thermostat is working normally.

You should have the thermostat replaced as soon as possible because allowing the engine to overheat can cause very expensive engine damage.

If you had a continuing overheating condition then I would suspect both the thermostat and the water pump. However as the overheating seems to be only temporary, and clears itself after you have shut down the engine and re-started it 10 minutes later (without further overheating arising) then I think you only have a faulty thermostat.

Please also check that the electric fans which draw air through the radiator are operating. These run on a temperature sensor and will switch on automatically once the radiator coolant fluid reaches a certain temperature and then switch off again when the fluid temperature reduces. You will hear them running once they start up. If these fans are not working the radiator coolant can quickly overheat in various driving and temperature conditions because there will be insufficient air flow through the radiator to cool the fluid. If the temperature sensor is faulty or has died, or if the electric motors running the fans are faulty, the fans will not operate.

I hope this helps.

The fans are controlled by a thermostat, and they are not dependent on the engine running for power. They run after the engine is shut off in order to bring the coolant system down to a safe temperature and prevent engine/radiator damage or coolant loss. This is normal on most cars with electric fans.

Bill B

That is nothing to worry about the fan remains running after the vehicle shuts off in order for the engine to cool down. Once the motor cools down sensors trigger the fan to shut it off.

As long as the fan eventually shuts off this isn't a problem,the fan will continue to run for a bit after the car is turned off,once it reaches a set temprature it will turn off.

How long does it remain on for?
This is quite normal. It should switch of once the radiator temperature drops..