[Jeroen]

Originally Posted by sanjeevs

if this feature is given for the newer generation cars, radiator fan running for additional minutes will have very little or no desired effect on the engine cooling effect in practical terms and at the same time draining the precious power from the battery if it is designed that way.

It’s quite normal on many modern and even not so modern cars. My 2002 car has it!

You seem quite convinced the engine designers got it wrong then? How come you appear to know better than all these different engine designers from so many different manufacturers? Any specific engineering and design insights you can share with us?

Jeroen

[autobahnjpr]

It is perfectly N-O-R-M-A-L . In the first instance it may give an impression that something is not right but this is a behavior for many manufacturers and many cars. I first witnessed it in Palio long back in 2006 or so when my neighbors palio radiator fan would continued running even after switching off the engine. This behavior is there in my Audi also and once my neighbor came running to complain that something is wrong with my car as the fan was still running.

Chill, there is nothing to worry.

[spgv]

My Fiat Palio did this often. AFAIK it was more than a minute.
My 2008 Grand Vitara too did this, though it was not common.

For a 80Watts Fan at 12V, current shud be 6.66Amps. Thats 0.22 Ah for 2 minutes. Car battery may be 60Ah.

[Mitadru]

Not very weird actually. Our 2008 Hyundai Santro does it. With temperature touching 43 degree Celsius in Kolkata our Santro does it pretty often. Our Slavia usually turns off the radiator as soon as we switch the AC off. But nonetheless I religiously practice the 1 minute idling rule after a drive. And if the radiator is running, I keep the engine on, until it has stopped spinning. If the OP is still worried, maybe he should keep an eye on the temperature gauge, it will give an indication of overheating, if this what he fears.

[sanjeevs]

Originally Posted by Jeroen

It’s quite normal on many modern and even not so modern cars. My 2002 car has it!

You seem quite convinced the engine designers got it wrong then? How come you appear to know better than all these different engine designers from so many different manufacturers? Any specific engineering and design insights you can share with us?

Jeroen

I am not at all mentioning that designers have got it wrong. I have not seen this feature in Indian car manufacturers like Tata , Maruti etc. at least to my knowledge. I was just trying to focus on the point that it is not so good feature to have wherein you don't have any plausible benefits on the cooling effect for the engine. If this was the case all the car manufacturers would have got this as a standard feature in their engine design.

[Jeroen]

Originally Posted by sanjeevs

I am not at all mentioning that designers have got it wrong. I have not seen this feature in Indian car manufacturers like Tata , Maruti etc. at least to my knowledge. I was just trying to focus on the point that it is not so good feature to have wherein you don't have any plausible benefits on the cooling effect for the engine. If this was the case all the car manufacturers would have got this as a standard feature in their engine design.

You are looking at it from the wrong way. Some engines benefit from it, some don’t. It is an intrinsic part of the engine and car design.

Older cars/engine and obviously every one with a mechanical fan is not going to have this feature.

The benefits of this feature are several. When the engine gets switched off there is a lot of residual heat left in the engine itself and the coolant system. Without coolant circulation the residual heat seeps into the coolant and some get dispersed through the air and convection). However, it means that certain parts of the engine could get way hotter than normal. These are known as hot spotsThat can present problem on starting when the engine is not cooled down. And it can affect the life of certain parts over time. To prevent all of this, the electrical fan is kept running for a short while after the engine has been shut down.

The fan does two things. It provides air cooling of all the various part under the hood and it cools the coolant in the radiator. A small temperature difference in the system will create some natural circulation. That is sufficient to ensure none of these hotspot occur.

Whether an engine benefits from this feature is depended on a number of factors. The engine design itself, coolant system, air flow under the hood etc.

As a general phenomena we see smaller engines making more power. And it is not just the size, the engine themselves are becoming smaller. So engineers crank out more power and torque and smaller and lighter engines. The downside of this is cooling becomes more difficult and more critical. For every advantage there tends to be a disadvantage as well. Engine design is always a compromise.

It has been mentioned on this thread that the fan will cool until the thermostat switches it off. That is not always the case. The natural circulation in many cases is not sufficient to provide that large a drop in temperature. Often the fan is just run for a given amount of time. The engineers have determined what is a good enough time period. On some cars, based on driving conditions prior to the engine shut down it might even vary the time the fan runs for a bit. It sounds complex. But it is pretty simple from a software point of view and doesn’t require any additional hardware.

Jeroen

[alphahere]

My Jeep Compass diesel does this. So does my BMW X1 diesel. Also did my Fiat Uno. I believe in the old vehicle it was more about how the air conditioning was wired. The Jeep does this if it is shut off mid cycle during a DPF regen. Same with the BMW. The DPF can reach very high temperatures during regen and the high speed fan helps to promote airflow around the area to bring temperatures back to safe levels for parking. They do not want to be held responsible for a parking fire.

[anilntny]

This seems absolutely normal, my Compass too is having same phenomenon.

[Gansan]

This is a common feature for all cars. If you had taken time to go through the owners' manual after buying the car, it would have been mentioned clearly.

[MT_Hyderabad]

This feature is not necessarily for the engine protection alone, but for preventing heat buildup in the engine bay in a stationary car.

[Jeroen]

Originally Posted by MT_Hyderabad

This feature is not necessarily for the engine protection alone, but for preventing heat buildup in the engine bay in a stationary car.

Which component(S), other than the engine and its various components, benefits from it you think?

Jeroen

[MT_Hyderabad]

Originally Posted by Jeroen

Which component(S), other than the engine and its various components, benefits from it you think?

Jeroen

Electrical components including ECU/ECM, Fuse box, Sensors and Paint of the engine hood are few I can think of.

[roby_dk]

Originally Posted by sanjeevs

I am not at all mentioning that designers have got it wrong. I have not seen this feature in Indian car manufacturers like Tata , Maruti etc. at least to my knowledge. I was just trying to focus on the point that it is not so good feature to have wherein you don't have any plausible benefits on the cooling effect for the engine. If this was the case all the car manufacturers would have got this as a standard feature in their engine design.

Wrong dear the same feature was there in my Safari Dicor 2011 model. It seems you didn't notice the same in these brands.

Edit: Same is present in 2017 Endeavor and 2019 Thar

[Jeroen]

Originally Posted by MT_Hyderabad

Electrical components including ECU/ECM, Fuse box, Sensors and Paint of the engine hood are few I can think of.

Not really a problem. Paint suffers more from UV than from heat. Your hood, or any more or less horizontal part of your car is likely to get a lot hotter in the blazing sun than from residual engine heat.

Same for plastics. Temperature can age many materials obviously, but it always a function of temperature and time. So in order to make a real (negative) impact it needs to be exposed to unusual hot temperatures for a long time.

These days a lot of the electronics, (e.g. ECU, TCM, BPM tend to be distrubted all over the car. ) one of the main reason of moving the electronic components out of the engine bay is water ingress.

The problems the engine might suffer from in case of too much residual heat are more of a direct mechanical kind. Metals warp, gaskets get damaged and so on.

To put it in a different way. Exposing an engine to high residual heats, say a 100 times is likely to have an exponential larger impact than the ECU a 100 times to that same residual heat.

So yes, there are some benefits to other components, but inmpractive I would think they are marginal. But I would love to hear what the real engine designer think.

Of course, the above is a theoretical example. If the engine life is negatively impacted by the residual heat under the hood, you are likely to see this cooling fan running with ignition off. If you have a car with the ECU fitted inside the engine bay you can be sure its well suited to take those high temperatures.

Jeroen

[V0id2003]

Originally Posted by sanjeevs

I am not at all mentioning that designers have got it wrong. I have not seen this feature in Indian car manufacturers like Tata , Maruti etc. at least to my knowledge.

I have seen the same feature on my facelifted Tata Harrier. The fan spins quite loudly after shutting it off. Especially during this year's summers and mostly after spirited driving in Sports mode