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Every time I change the E53 after coming back from a trip it starts blowing the fan and heat comes out the sides of the car to the point the garage gets very hot. I stopped charing last night and took the car out on the drive way in the morning to charge it and it didn't start the fan! I dont know is it trying to cool the battery or warm it for charging? Have any of you noticed this?
Every time I change the E53 after coming back from a trip it starts blowing the fan and heat comes out the sides of the car to the point the garage gets very hot. I stopped charing last night and took the car out on the drive way in the morning to charge it and it didn't start the fan! I dont know is it trying to cool the battery or warm it for charging? Have any of you noticed this?
Thanks!
It's definitely not trying to warm anything after driving. Things are plenty hot. It's probably trying to cool the engine since you just drove it or cool the batteries. With you plugging it in, it has plenty of energy to turn on the fans to help cool things down. Either way, the running fans are not making your garage hotter. The car is doing that on its own. Fans only cause heat to be radiated faster by increasing air flow. The fans generate additional heat due to friction, but compared to the car it's negligible. In 2 hours, with the fans coming on, the garage would be cooler than it would with them staying off.
I don't have a plug-in but my car will turn on the fans when I shut the engine down if it's hot enough. I don't notice it often. Either way, parking a car in the garage after a drive, especially a long one, will heat up the garage. I will often leave the big door open for a few hours to help allow the heat to escape.
Hadn't had my coffee yet when I posted that. I know the car is a plug-in hybrid, but spaced it thinking it was a straight ICE, where obviously, you'd want to pop the hood to hook up a battery charger.
Hadn't had my coffee yet when I posted that. I know the car is a plug-in hybrid, but spaced it thinking it was a straight ICE, where obviously, you'd want to pop the hood to hook up a battery charger.
Somehow I suspected this, but I just had to ask. 🤣
First of all, yeah I don't pop the hood . This is almost every time I charge and my garage is not hot but it does get hot after this. Yes you are correct it does stop after a while. Usually less than 2 hrs as the battery is fully charged by then. I just do not see this with others cars I had, like EQS and EQE, they charge quietly regardless of how long my trip is and how hot it is.
The E53 has a much smaller battery but it seems to heat pretty easily.
Last edited by shakoomakoo; Aug 23, 2025 at 12:36 PM.
First of all, yeah I don't pop the hood . This is almost every time I charge and my garage is not hot but it does get hot after this. Yes you are correct it does stop after a while. Usually less than 2 hrs as the battery is fully charged by then. I just do not see this with others cars I had, like EQS and EQE, they charge quietly regardless of how long my trip is and how hot it is.
The E53 has a much smaller battery but it seems to heat pretty easily.
The EQS and EQE are all electric while the E53 is a plug-in hybrid with a 3.0 liter inline 6 for the gas part of the hybrid equation. I'm sure it gets much hotter then an all electric vehicle. Have you done an all electric round trip to see if the fan still comes on? My guess is the fan is cooling the gas engine and with it plugged in, it takes the opportunity to do that when it's hot. Just a guess. Have you looked in the manual for a clue as to what it might be doing?
For whatever it is worth, my BMW X5 plug in hybrid turns on fans randomly when charging. I gave up trying to figure out the logic. These cars are all the same bits and parts so imagine it is a similar system.
When charging the batteries of my electric devices (riding lawn mower or say the electric generator or the chain saw etc), the fans come on, and things get pretty noisy. I think the system is trying to keep things cool, to lengthen the life of the battery.
Also, in turbo-charged cars, coming to a stop after a drive, and turning the car off right away, I believe the mild-hybrid may be running the coolant through, and turning on the fans, to cool the system down. Again, a self-protective measure.
I personally drive gently with my cars for the first few miles, while the system (the engine, the drive-train components and the other sub-systems) is reaching operating temperatures. And similarly, at the end of my trip, during the last few miles, I drive gently to allow the cooling process to take hold, before shutting off the car. Just a protocol that I follow with all of my cars, especially the turbo-charged cars.
The EQS and EQE are all electric while the E53 is a plug-in hybrid with a 3.0 liter inline 6 for the gas part of the hybrid equation. I'm sure it gets much hotter then an all electric vehicle. Have you done an all electric round trip to see if the fan still comes on? My guess is the fan is cooling the gas engine and with it plugged in, it takes the opportunity to do that when it's hot. Just a guess. Have you looked in the manual for a clue as to what it might be doing?
Yes it does this even with an electric only trip. I have not looked into the manual.
The setting for pre-entry climate control might be tripping you up. The fan you may be hearing could be the heat exchanger fan. I haven't had this happen to me that I have noticed, but I always charge off our solar at work and have the car locked while doing it.
Last edited by Steven H-R; Aug 25, 2025 at 11:35 AM.
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. This is almost every time I charge and my garage is not hot but it does get hot after this. Yes you are correct it does stop after a while. Usually less than 2 hrs as the battery is fully charged by then. I just do not see this with others cars I had, like EQS and EQE, they charge quietly regardless of how long my trip is and how hot it is.
