Hi All,

 

I noticed on my Octavia RS IV PHEV after a longer but soft run (3.3 l/100km and 2kwh/100km consumption) right after stopping the engine the fan would come on but stop immediately. (HV battery 3%)

If I plug in the charger, the radiator fan starts immediately and runs a few minutes with the fan speed gradually slowing down to zero.

Also to note that my home is located on a hill going like 800m on slow speed between 10-30 km/h

Other times running motorway, after stop, no fan on even on constant 120km/h for an hour or so.

All these on moderate ambiental temperature 15-25 C

I am thinking about occasions when engine could not cool down enough due to different situations and needs the engine and turbo to further cool down.

Also, the car in hybrid mode always turn off petrol engine when no throttle which would be normal but not if hot.

So why is the car turning off the petrol engine if the engine is hot and would need to run at light speed to cool it down? Maybe the speed not enough to cool it anyway? If so, why isn't it running the fan after stop the car only with charger plugged in? Isn't it more important to cool the engine down?

 

 

Edited 8 May, 20242 yr by axw

That is normal, don’t wory about.

 

Thanks!

Hello my friend. It was really normal or u had problems later?

Hi!

Yes it was normal to behave like this, the ECU won't turn on the fan every single occasion to save battery but if connected to charger will use this opportunity to cool down. I understood there are complex cooling mechanisms which involve different conditions like HV battery level, outside temperature, etc. There are three cooling circuits if I am not wrong, one for battery, one for ICE and a third one (smaller radiator in front of the big one) for hybrid system. Once I also noticed the cooling agent was circulating while the car was stopped for a while. No issues since then, except an intermittent coolant sensor wire that ocasionally started the cooling fan but this issue was different from my first observation.

46 minutes ago, axw said:

There are three cooling circuits if I am not wrong, one for battery, one for ICE and a third one (smaller radiator in front of the big one) for hybrid system.

You have two. One for ICE and second for HV. HV one is connected to AC circuit via heat exchanger and dumping heat there.