V50 General : D5 heater in cold weather

[robg]

I got in the car for a 10 mile journey this eve. Display showing 5 deg C. I thought it was gonna take ages for this big diesel lump to warm up. The car has been parked since the weekend. I put on my heated seat and in less than 90 seconds or about 1/4 mile the heater is blowing warm air! The heated seats were only just starting to work. Fantastic!! It still took about 3 miles for the engine temp to show much heat.

So how does it work???

I thought it could be the air con being used in reverse as a heat pump so i turned AC off but the air remained warm. Anyone know how they do it?

rob

[seany]

I too am mightily impressed at the low warm up time for the D5 (S60)

All my previous diesels were barely warm by the time i got to work

[treidlia]

Its mightily impressive in the 2.0D also.

Form perusla of the engine compartment (in the 2.0D) there seems to be a direct coolant circuit to take heat from the exhaust manifold to the passenger cabin heater matrix. So the heater matrix gets heated up prior to the engine getting up to temperature. I'm not too sure if it is a separate circuit or part of the main circuit, but I don't seee the dash thermometer coming up particularly quiclky, so it looks to me like some sort of an ancilliary circuit.

Anyone confirm/refute my theory?

either the heaters doing great or youve got an engine fire!makes me remember the british gas ad,`come home to a real fire`!

could it be that the hot air to the cabin is fed straight from the crankcase,because this warms up first,and then is warmed by the heater matrix from the radiator.its a real puzzler

[Viper_7]

when it's around 5c like it was this morning I've got to travel about 7 miles before the water Temperature gauge is normal.
It takes about two miles before it even thinks about moving!

but yes the heat comes through quite soon - I wouldn't say hot! but it's warmer then the engine temp would have you belive.

[ptecuk]

I believe diesels for cold climates are fitted with a PTC heater that operates immediately. It is electrical which has a low resistance at low temperatures and therefore takes more electrical current and can give up to a maximum of 1000 watts of heat. As temperature increases the resistance increases and the current and heat decreases. I have a UK S40 2.0 litre diesel that also warms the cabin quickly in cold weather. I am not sure whether this is fitted to all diesels or just those for cold climate markets. If the latter then perhaps the UK is considered a cold climate.

[7050man]

Just to add my twopenneth. Agree with all above comments. Vents do start to blow warm air way before temp gauge has moved.
In these cars in certain countries, Volvo appear to fit two types of pre heaters to their cars.
There is either a diesel heater or electric mains powered plug in type. These are designed to warm the engine block prior to engine starting, not only to ensure quick warm up under very cold conditions, but also to improve fuel economy.

This idea must be a Swedish thing as my previous car (3.0 TiD V6 Saab 95) had one of these and it was very effective as you could program it to come on at certain times and it would warm the entire cabin as well as the engine block. It had to be used regularly or the oil jets would block.The other thing was that it would run the climate control and so if you left it on for more than 30 mins, then there was a risk it would kill the battery. It also sounded like a jet engine when running, which used to get a few funny looks from the uninitiated. I managed to fool the kids for a few weeks that it had a "jet engine for rapid overtaking" (it was a quick car as well).

It would be good if Volvo put this on the UK options list, I'd certainly specify one on my car.

if it runs at a kilowatt,does that mean you plug it into the mains like the old landrovers overnight