"claimed" Tank Range Vs Reality

February 28, 2011

RE the stuff about 'Putting the heater on' when the engine is cold

& the thermostat opening & the choke staying on longer.

(or driving along & putting on a heater & cooling the coolant system down again)

nope, not correct.

The 'Thermostat' stays closed untill the engine coolant is up to temp, to get the engine to running temp,

then the thermostat opens & the coolant circulates around the system & to a heater.

The thermostat will not open early because the heater is switched on.

Obviously if the ambiant temp outside is cold say at minus & the coolant is sitting very cold it takes longer to rise to say 88 degrees than if its 15 c ambiant temp & the engine coolant is warmer,

The air being taken in to the Airbox is also cooler,

this is how the modern engine has sensors & air flow meters & auto chokes.

Rather different from the days of pulling out the choke giving less air & more fuel untill the engine runs smoothly,

same principal tho, just not effected by switching on a heater,

other than the same as when switching on Air Con while sitting, more electrical drain so more revs from the alternator,

so more fuel used.

(same as putting on the lights,heated rear screen, radio etc, more power needed for the Battery drain so more revs used when the alternator is kicking in)

Sometimes it can be argued that less fuel is used tho, because the engine comes up to temperature quicker.

You will feel in some vehicles that the radiator pipes are warm before the thermostat opens & some heat goes to heaters,

this is because there is a small bypass hole in thermostats to prevent air blocks by allowing a small flow.

No heat in the engine & no thermostat open

& no heat from the heater in most cases of vehicles unless there is electrical heater systems,

start a car & drive it is often the cheapest way to get a car warm & up to optimum running temp,

& any automatic choke system off.

Sitting with your engine running to warm up & de-frost the car needs taking into account if you are driving 10 miles to work & then 10 miles back in winter etc.

Your mileometer isnt reading any miles sitting going no place/parked, so no point looking at fuel consumption by milage on those days IMO.

george

PS how would colder air temprature make there more 'road friction'.

("denser air"?? car we are talking about here, not a Jumbo Jet!

& cars in the UK,

where i live it was minus celcius or below for over 5 consecutive weeks this winter, that was in the North, how often does the majority on the UK sit at low temps?)

Colder ground/tar/asphelt has less friction surely,

which is why you would fit 'winter/cold' weather tyres that give more friction/heat to the road at colder temps.

by the silca working better than the 'summer tyres'rubber which give better traction/adhesion in warmer temps.?