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

Hello Dave,
I just completed the repair of my defrost vent/register blend door actuator. Here is a quick summary in case it can assist someone else on the site.
PROBLEM: No air circulation from the defrost vents that are on the top fascia/instrument panel near the windscreen/windshield.
FAULT STEPS: Turn on climate control system and moved through all options for both cooling and heating. Move through all vent option positions: floor only, dash only, mixed floor and dash, defrost. All options worked correctly except no defrost ventilation. Selected auto option and rear defrost, then front defrost. Again, all options worked correctly except no defrost air circulation. I reviewed Technical Bulletin JTB00066 titled, Ticking/Bubbling Noise Behind Fascia/Instrument Panel. I have experienced this condition, but it never prevented any functionality of the climate control system.
CONCLUSION: Since all options worked correctly except the defrost air flow I decided to replace the defrost vent/register blend door actuator, part#: XR8 57885
REPAIR: I followed the repair procedure in the Service Manual in section: Electrical > Climate Control > Control Components > Defrost Vent/Register Blend Door Actuator > Removal and Installation. The Instrument Cluster needs to be removed first and that can be found in 413-01 Instrument Cluster, Removal and Installation. The front instrument finish panel comes off easily if you use plastic non-mar removal levers. Just make sure you are close to the clip locations so as not to stress the finish panel and the plastic clip retainers. The instrument panel comes out easily with 4 screws for the cluster finish panel (philips) and then the panel itself with (4) 7mm screws. The 2 electrical connectors on the back of the instrument cluster are the type with a lever that needs to be lifted and moved from top to bottom as they basically act as a lever to release the connector. (When reinstalling they help seat the electrical connector.) The left and right sides are color coded. The actuator is located exactly where the picture says it is; yes, way back there. It can be removed with some careful positioning of hands and tools. It is a tight fit. I removed the 3 actuator screws from the front and the electrical connector from the bottom. When you mount the new actuator be careful to get the pin on the actuator lever into the vent door arm. Also, near where the furthest screw from the front, on the actuator, there is a hole where a pin goes into the actuator, this helps make sure the actuator is properly positioned.
This repair solved my defrost problem and I hope it helps someone.
Here is a picture of the inside of the old actuator. You can follow the broad circuit traces to see where the positive and negative pins are located.

Hi Steven. Thanks for your very comprehensive reply. It’s great to see the forum working. I’m sure others will find your post very helpful. Still loving my Jag.

Well well well! I can’t believe I’m back on this topic. some of my previous posts have related to heating or lack of it and cooling or lack of it. I’ve replaced various parts over time including the cooling fan after a recent engine overheating issue. I also noticed fluid residue around the crimped hose joints at the heater core end. This explained my slow loss of coolant. Anyway I decided to go with a new set of pipes and all is working well. No more leaks… but I had got used to the slow heat build up in the cabin and that was my “norm” Maybe 10 minutes of driving before any comfort in the cabin on cold days. With the new pipes fitted… almost instant heat!!! This made me investigate the old pipe set. How I was getting any heat I don’t know because under previous ownership and I guess to overcome a failed and constantly open dual flow valve and to save money They did this…

I guess it was some scrap they had handy… interesting that there is a thread inside?
Has anyone seen anything like this before?