No heat in cabin...Air Lock?

My 2003 is supposed to hold 10 litres of coolant. when I drain at the valve at bottom of radiator I get maybe half that. Should I expect a different result?
Still chasing No heat to cabin. There is no heat in the two inlet pipes or the return pipe,
I have replaced the dual flow valve, Aux pump thermostat and water pump.
There is an air bleed in the coolant tank…but is it possible to still have an air-lock somewhere…and if so, how can I fix it. I’ll be really happy if someone can help.


I don’t know the S-Type, but try to park in such a way that the reservoir is elevated. Turn on the heat to full. Then run the engine and keep topping up. That is assuming it has no bleed valves, etc. Or a special procedure.


Thanks David. I should have mentioned that mine is the 4.2 V8
Instructions are to simply remove the bleed which is on the coolant tank and then fill . replace cap and bleed screw. run with heater on and re-check/top-up.
Thanks for the tip though. I will try it ASAP.

Just in time for Aussie Summer I have fixed the problem and now have heat in the cabin,
In Tuning for Speed by Phil Irving, he strongly recommends that everything you do is documented so you can review and compare. I should have put this in to practice!
I had done so much in trying to find the solution that over time I forgot everything I’d done.
Water pump, Control Board checked,Thermostat, Auxiliary pump, Dual Flow valve, Radiator, Top Hose - all these parts were faulty. Flushed heater core both directions. still no heat! THEN I realised that I had only flushed the return line and core but not the two inlets! With garden hose attached there was an initial hesitation before water freely flowed through both pipes. Eureka! reconnect everything… still no heat! …… A local Jag parts man asked me if I’d used a genuine Bosch valve or a Chinese copy. I couldn’t remember until I went home and looked up my paper work. Sure enough, I’d gone for a AUD$70.00 Chinese version. “Lucky” Phil the parts man said they don’t use these any more as they are very unreliable; He was talking approx. $300.00 for a Bosch. Anyway ….I made up an adaptor so I could leave the valve in place but test the flow under water pressure… again after a sluggish start I now had water through the valve…Everything reconnected AGAIN…… and I now have heat through the pipes and of course heat in the cabin… So, there was more than one problem in the cooling system / coolant flow system. I will monitor the current valve and replace with a Bosch if my problem reappears. On the air side I found a blend door actuator out of calibration and not connected. I fixed this today so looking forward to some quality time with my S. This has been a test/fix over time…All the more reason for me to have kept a note book! We live and learn.


Hello Dave, I have a 2008 S 4.2 and performed many of the same tests and replacements you have completed. I replaced the HCV with a Gates mfg unit (USA) and expansion tank with a new Jaguar tank. I did not have heat until I drove the car about 1/4 mile and evidently got the water to circulate completely. I had previously topped it off and bled the system according to the manual. Now, I have a perfectly functioning heat/cool system EXCEPT when I select front defrost I hear the doors move, the fan kicks into the higher speed, but no air from the defrost vents at the windscreen. I am wondering if the blend door actuator might be out of calibration as you mentioned in your post. Can you provide additional detail as to how you made this calibration? Much appreciated. Steve

Hi Steven, good to hear from you. Regarding the calibration of the blend door actuator that was faulty.
Mine is Right hand drive and the problem door is on the drivers side. very hard to get to without a fair amount of removal. I had to remove the trim and instrument cluster first.
It appears that someone had been there before as the link arm wasn’t even connected even though all the parts were there and nothing was broken. Anyway…reconnecting did not solve the issue. My actuator was a Ford item. I was not convinced that “drive arm” was in the correct position as I had difficulty attaching the link arm. I found a youtube clip by AC Delco which talks about the issue. Both the markings and the pins on the AC Delco are different to my Ford item so… Mine had a straight line on the case which I assumed was the fixed reference. I then took out the screw holding the arm to the shaft. One side of it had a distinct “Flat” This flat was not lined up with reference.As the pins on mine were different I just used trial & error to find which pins worked…sorry I cant remember which! anyway… using the 9V battery as shown in the clip I was able to get the shaft to turn so the flat and reference lined up. It then fitted back easily and now works fine, Sorry I cant be more explicit but the AC Delco clip may be more useful. This first one is the one I copied from but there is another which uses an OBD tool

Good luck with your S and please let me know if you get on.
There is another youtube clip on how to remove the instrument cluster or there are other blend door actuators that you can access by removing the glove box.
Cheers, Dave