Heater blowing cold !

[ronnie2507]

I have a 2001 xkr, recently the heater has begun to only blow cold air even though the display has been set to blow hot !
The temperature of the car is running normal and i dont appear to have any other faults, any ideas ?

[BestGear]

Hi

The colling system on the XK is slightly more complex than most cars, in that the heater has its own water pump.

I have attached a diagram showing the water path. The pump and valve are 5 and 7.

Key for the diagram:

1 Cooling fan motors and shroud
2 Thermostat housing
3 Water pump
4 Throttle body
5 Heater water pump
6 Heater core
7 Water valve
8 Expansion tank
9 Degas bottle
10 Radiator

http://i265.photobucket.com/albums/ii23 ... ling-1.jpg


The first things to check I guess would be the valve to check its not remaining closed - could be an electrical issue or mechanical. (There are actually two non return valves - unlikley to be the problem though.)

This diagram shows the heater valve (3) and pump (2).

http://i265.photobucket.com/albums/ii23 ... heater.jpg

I assume the coolant level is correct and that no work was done prior to the fault appearing?


Hope that helps.

David

[ronnie2507]

Cheers David i'll have a look

[MarkyM]

Thankfully your not likely to need the heating in the summer (here's hoping)!

I had the same problem last year and it was the heater pump that had gone kapput. You should first run the engine with the cap off the expansion tank until it overflows just to try to clear any blocked air.

Then run some radiator flush for about 1500 miles (in case you have a blocked matrix) remembering to backflush to remove any accumulated gunk.

Then if it's still running cold you'll need to look to the valve and pump.

Let me know if you need a new pump as I have a reconditioned one (bought from Ebay but the coil was damaged so got Jag specialist to refurb my original and the duff replacement.

Price from Dealer is from memory £223 inc if it's the pump.

The pump replacement is DIY but will require that you remove the air filter and snorkle and that you have quite small hands.

Regards

Mark

[Roger.brearley@yahoo.co.uk]

The first thing to check if your heater is blowing cold is Fuse number 3 located in the engine bay on the near side . If your front fog lights don’t work and the fog light switches and traction control switch indication lights don’t work this is another indication that the fuse has blown. This fuse also controls the auxiliary siren( the one that chirps or in most cases doesn’t!) I disconnected mine before changing the 5 amp fuse number 3 and now all is working fine so much so that I have to turn the heater off now because it is too hot. Hope this helps, I was ready to pull my car to bits to get to the heater pump which if you read other forums they all seem to say that this is the problem.. The old saying “ check the light bulb first!!

My car is a 1997 XK8 Convertible withe 71000 on the clock