Hello,

Should the aux heater / FBH be on when the engine is up to temperature?

I’ve noticed in the past two evenings after a 20/30 minute drive that my FBH has been on when I’ve got out of the car as it stinks of fumes and you can see it coming from the FBH exhaust outlet if I shine a torch in that area.

Ambient temp has been above 5 degrees, heating in the car set to 25. Engine is fully in the middle for coolant temp. Only thought it engaged at first start up if below 5 degrees if not pre-set.

Thanks

2012 TDV8 Westminster

On my MY11 4.4TDV8..but should be same as MY12

FBH will operate as auxiliary heater to maintain temperature of the engine as programmed

For pre-heat, FBH will warm cabin <15 degrees
FBH will warm engine only <-20 degrees

On short journeys, i notice FBH is still operating when i shut engine down - like 5 or 10 minutes - but not 20-30 minutes
You comment was that FBH was not still operating but had been on. Could be there is still residual smoke coming from the FBH a while after it has shut down.

On my RR, heat settings inside the car make zero difference.

It’s also a symptom of a leaking thermostat as the FBH tries to maintain engine temperature against excessive coolant flow through the radiator. 2012 TDV8 Vogue (L322)