I lost 10 degrees

macafee2 · 29th December 2020, 15:11

This morning I activated the FBH and let it run, not sure for how long but then drove mile and a half to two miles. I sat with the engine ticking over and the FBH still running. Although I had turned the FBH off before starting the car, due to outside temperature and coolant temperature it had turned itself back on.
While sitting there I entered the cars diagnostic mode and it showed the water temperature as being 78 degrees. I turned the screen demister on and watched both the coolant temperature needle drop and also the diagnostic readout drop by a massive 10 degrees.

Turning the demister off saw the read out start to climb.

Many moons ago my dad told me to stop a car overheating when stuck in traffic, turn the heater on to hot and turn the fan on. In time I guess the coolant temperature would still climb but may well take some time.

macafee2

kelvo · 29th December 2020, 16:08

I recall having a diesel Focus (our works on-call car) and being stuck in traffic in freezing temperatures and watched the temperature gauge dropping whilst sat there. Even our Mondeo now takes a good couple of miles for the gauge to get off the cold mark.

It's probably the reason that the heater fan on the R75/ZT starts on a low setting to start with, otherwise if you stuck it on full from cold it would probably cool the engine down faster than it could heat up.

I know if I've been out with the bus in cold weather, I'll let it get up to temperature before putting the heater blowers on, even so even after a run the radiator is only lukewarm, so the saloon heaters are just as effective at cooling it.

29th December 2020, 15:11	#1
macafee2 This is my second home Rover 75 Saloon & Tourer Join Date: Sep 2012 Location: Lincoln Posts: 14,926 Thanks: 1,630 Thanked 3,032 Times in 2,181 Posts	I lost 10 degrees This morning I activated the FBH and let it run, not sure for how long but then drove mile and a half to two miles. I sat with the engine ticking over and the FBH still running. Although I had turned the FBH off before starting the car, due to outside temperature and coolant temperature it had turned itself back on. While sitting there I entered the cars diagnostic mode and it showed the water temperature as being 78 degrees. I turned the screen demister on and watched both the coolant temperature needle drop and also the diagnostic readout drop by a massive 10 degrees. Turning the demister off saw the read out start to climb. Many moons ago my dad told me to stop a car overheating when stuck in traffic, turn the heater on to hot and turn the fan on. In time I guess the coolant temperature would still climb but may well take some time. macafee2

29th December 2020, 16:08	#2
kelvo Gets stuck in MG ZT 190 SE Join Date: Oct 2017 Location: Chatham, Kent Posts: 569 Thanks: 22 Thanked 163 Times in 135 Posts	I recall having a diesel Focus (our works on-call car) and being stuck in traffic in freezing temperatures and watched the temperature gauge dropping whilst sat there. Even our Mondeo now takes a good couple of miles for the gauge to get off the cold mark. It's probably the reason that the heater fan on the R75/ZT starts on a low setting to start with, otherwise if you stuck it on full from cold it would probably cool the engine down faster than it could heat up. I know if I've been out with the bus in cold weather, I'll let it get up to temperature before putting the heater blowers on, even so even after a run the radiator is only lukewarm, so the saloon heaters are just as effective at cooling it. Last edited by kelvo; 29th December 2020 at 16:14..