Today I noticed that on my 2008 400h the radiator fans seem to start only when the engine temperature is pretty hot - like after some hill climbing in very hot weather.
I was thinking to re-check that with the OBD interface (that I didn't have with me today) and the Torque app, which I'm sure that can show the coolant liquid temperature, among other things.
But it would be useful to know if anyone is aware of the correct temperatures at which the fans are supposed to turn on/off.
I'm posting this here rather than in the hybrid section because I suppose that it should be the same also in the 330 that has the same engine, if not also in the 350.
Thanks in advance!

 

On my RX330 the fans come on at 207 degrees and turn off at 203 degrees from what I just read in the service manual. That is without the A/C on.

 

Mine run all the time but they don't make much noise. But then my AC is always on. Is your AC on when they are not running?

 

In Rx400h the radiator fans can be also triggered by the inverter coolant temperature.

After stopping the vehicle I haven't experienced fans staying on by the gasoline engine as switching the A/C off has turned fans off always. I could think it's (3MZ) cooling system is less stressed than in non hybrid version.

But it is good to ensure that sensors work and it won't get too hot. Does the engine warm up normally? Stuck thermostat could cause it runs cooler most of the time but it would cause problems mainly in winter.

 

Ok, 207 - 203 sounds reasonable.
I'll check that with Torque app the next time I'll use the car.

In reply to other questions, yes, the ICE seems to warm up normally, also in cold weather, so I don't think the thermostat is stuck.
And no, when the fans aren't running, the A/C is off. Turning the A/C on seems to turn also the fans on anytime, regardless of cooling liquid temperature.

Will post my findings asap, cheers for now!