Why does my cooling fan run after shutting the engine off?

The after-running of the cooling fans is deliberate and can sometimes last up to 16 minutes after switching the engine off. The after-running process prevents excessive engine compartment temperatures caused by the diesel particulate filter regeneration cycle.

What happens to the coolant when the engine is turned off?

When the engine is running, the coolant circulates from the engine and flows to the radiator, where heat is dissipated. When the engine is turned off, the coolant doesn’t circulate, and the heat stays trapped, therefore prolonging the engine from cooling. Running cooling fans help cool down the engine even after you turn off the car.

Why does the radiator fan run all the time?

The radiator fan may run up to five minutes and sometimes longer. Unless there is an electrical issue, it may stay on all the time until it drains the battery. When the engine is running, the coolant circulates from the engine and flows to the radiator, where heat is dissipated.

What happens when you shut off the cooling system?

SteveF has it right…With all engine and cooling system designs, when you shut off the engine, you also shut off the water pump. Coolant trapped in the heads can boil as it absorbs the heat in the metal engine parts with no way of transporting this heat to the radiator.

Is it OK to leave the cooling fan on when the engine is turned off?

Car Fan Still On When Engine is Turned Off You park your car, turn off the ignition and start walking away. Then you notice the engine cooling fan is still running even though the car is turned off. It is ok for the engine cooling fan to keep running for a few minutes after turning off the car.

Is it normal for a car fan to run all the time?

This is normal in many vehicles, such as BMW or Mercedes-Benz. The radiator fan may run up to five minutes and sometimes longer. Unless there is an electrical issue, it may stay on all the time until it drains the battery. When the engine is running, the coolant circulates from the engine and flows to the radiator, where heat is dissipated.

Why does my blower motor not shut off?

All of sudden the fan motor started running on high speed and will not cut off of high no other way than the ground off the battery, could not find on fuse panel the fan fuse. helpful? To clarify, are you talking about the engine cooling fan (under the hood), or the blower fan (for heat and A/C)?

When does the fan stop running on a TDI?

When the temperature falls into acceptable range the fans will stop automatically. Bonus point: some new TDI owners have also reported an odd odour describing it as a “burning smell”.

How long does a VW cooling fan last?

The thought of walking away from your Volkswagen with the cooling fans buzzing away leaves most people with images in their heads of dead batteries and tow trucks. Rest assured—this is in fact normal operation. The after-running of the cooling fans is deliberate and can sometimes last up to 16 minutes after switching the engine off.

Why does my car fan run after Turner off?

Fan runs after car is turner off drains the battery. After having my battery replaced, I noticed my engine light was on and my fan was running “hard”. It also runs for 10 seconds after my car is turned off. Diagnostics stated “cooling system malfunction”.

What are the symptoms of a bad cooling fan relay?

1. Engine running hot One of the first symptoms commonly associated with a bad or failing cooling fan relay is an engine that runs hot or overheats. If you notice that your engine is running at higher temperatures than normal, that may be a sign that the relay is not functioning properly.

What happens to the engine when the fan clutch fails?

As the fan clutch is one of the main cooling system components, it is very important to the proper operation of the engine. When it fails, the engine can be put at risk of serious damage due to overheating.

When do you turn on the fan relay?

When the correct parameters are met, a temperature switch or the computer will activate the relay, which will allow power to the fans. The relay will usually be activated once it is detected that the vehicle’s temperature approaches excessively high temperatures.

Why are my aux and main cooling fans not working?

Cooling Fans: Both Aux and Main Cooling Fans Have Stopped Working… Both aux and main cooling fans have stopped working. Turning on A/C or elevated engine temp doesn’t make either fan come on. I have replaced the Main cooling fan relay but didn’t help. Not sure if there is anything else that controls both fans or would cause them both to fail.

What to do if your computer cooling fan won’t run?

Replace the cooling fan relay with a new one. A stuck closed relay is the only thing that can operate the cooling fan continuously with the key off. The computer looses power with the key off and the same applies to the coolant temperature sensor. The relay, however, has direct power to one side, the same as a light switch.

Why does the cooling fan run after the engine is shut off?

The rise in the temperature of the water after the engine is shut off is because of the residual heat in the engine and the lack of further airflow across the radiator – hence the running of the fan. SteveF

What causes a cooling fan relay to stop working?

Cooling fan relays can stop working for any number of reasons. Common causes for relays going bad include: There are several ways to tell if a bad cooling fan relay is to blame for an overheated engine. The easiest method is to start the engine and then turn on the air conditioning.

What happens if one fan fails to come on?

If one or both fans fail to come on; the lack of additional cooling provided by the fan may cause poor A/C cooling performance. Also, it may cause the A/C compressor to overheat and fail. The engine may also run hot and overheat, too.

Why does my AC fan not come on?

When the ac is of the radiator hoses both become same heat after a while and the overflow reservoir starts boiling over and the fan do not kick in. Any advise please. You might have an initial temperature sensor which causes the fan to come on when the temperature begins to rise; that sensor might be defective.

How does a radiator fan work when the AC is on?

The electric radiator cooling fan assembly is controlled by a thermoswitch located in the side of the radiator. At higher coolant temperatures, the switch closes to start the cooling fans. Any time the coolant temperature rises to higher than normal levels, the fan will start and continue to run until coolant temperature returns to a normal range.

Why are the cooling fans not working on my car?

Many other issues can cause the engine to run hot or overheat. Rather than uncommonly high engine temps, the driver may notice that the cooling fans have stopped running. A faulty or broken relay cannot deliver power to the cooling fans. In turn, the unpowered fans won’t run, leaving the radiator to its own devices.

Is the radiator cooling fan in auto shut off mode?

Auto shut off mode was active (fuel saving mode). As some point along her 20 mile trip the radiator cooling fan came on. I thought this was odd due to the air temperature. At stops the engine shut off as expected.

Can a car cool with the engine off?

There probably would be nothing wrong with letting the engine cool “by itself” (which is what happens if the design removes power from the fan when the ignition is off), but since the normal operation of most cars is to run the fan when the water temperature exceeds a set threshold, it does so even with the engine off.

Why does my car have a radiator fan?

You probably already know the purpose of the radiator and the cooling system in your car. When you are driving fast, the wind is passing through the radiator to cool the coolant down without issues, but when you are driving slow, there is no wind pushed through the radiator. This is why we use a radiator fan.

Why does my cooling fan run after shutting the engine off?