Had the same problem on my X300 96 modell.

The fault on my car was the elctric coolant pump. Dismantled it because a new on i thought was quite expensive and changed the coals as they were totaly worn out.

Works just fine for me now. Both the valve and the pump is located in the engine compartment near the brakebooster.

 

Hello!

The valve seems to switch open and closed ok, and the heat is a LITTLE warmer than the outside air. I'm not sure about the pump. If you don't mind, what exactly did you have to do to get yours working? Thanks! Its starting to frost here and I need a defroster!!

 

If the pump isn´t bussing when you have the car running and the temperatur on hit its most likely not to work.

I tok mine apart and replaced the "coals" maybe theyre called brushes. I took brushes from an seized Volvo external heater that was seized. the size needed to be adjusted though.

Not sure if you can buy just the brushes somewhere but maybe you have a sad batteri drill laying around or something like that a brush is a brush and if you can fit it it will work

 

I have a no hot air situation. Re-circ pump is running, solenoid valve functions when taken off the car but doesn't seem to work on the car 6.2 volt feed. I have changed the air con ecu which cleared all faults apart from 23 no gas in the air con (this has never affected hot air requirement in the past). Thrashed it down the road and back and it blows luke warm air. Changed the the little fan that draws air from the saloon which was so clogged up with fluff it couldn't have been drawing much air. I have a donor car and i think the next thing is to change over the solenoid operated valve. Does anyone have any ideas on what it could be?
Thanks
I am freezing!
Charles

 

You appear to have sorted through most of the possibilities. The solenoid valve switch would answer that question, but another possibility is the heater core being partially plugged. I have read of that in the forums, and backflushing the core by connecting to garden tap was successful in at least one instance.

 

There are a number of heater (lack thereof) threads here, this one doesn't really seem to be as informative as many of the others, though the grains are here. From what I can surmise, the list of possible causes in descending probability include:
Thermostat stuck open
Heater core partially obstructed (TSB's released on this issue)
Electric heater pump brushes worn out
Air pocket
Water valve stuck closed*

*I've listed the WV as least probable even though I spent the last 2 or 3 winters rapping on mine with a rubber mallet and feeling like that made a difference. In reality, it was probably just the car sitting still with the cabin heating up with what little heat was getting through while I was outside hammering the WV. Besides, the water valve is normally open (Ok, any EE's in the crowd will claim the "energized" state is "normal" so it is a "normally open" valve, but it's not my fault they were taught to think backwards from other engineers.) Anyway, my contention is that the valve is open far more often than closed and if it sticks it would be more likely to stick open rather than closed. My initial problem was a t'stat stuck open, but that only took me from "no heat" to "a little heat." After flushing my entire system with distilled water, and my heater core backwards with a garden hose, then replenishing with Zerex G-05, I'm back to a fully functional heater core. Had that not panned out, I would've attempted soaking the core in flush-solution overnight as Motorcarman posted in another heater-thread. Lot's of info here, but you may have to search for it. There are how-to's on electric water pump brush replacement and core-backflushing, etc. Keep at it and you'll get it sorted.

 

On another thread it was suggested to disconnect the rear upper pipe from the WV, remove header tank cap and fill open pipe with coolant until it runs out of the valve. All this did was to overfill the header tank! Have now followed Jaguar's purge routine and it really didn't make any difference. Last resort disconnected upper front pipe from WV which is the "out" from the heater matrix with engine running and header tank cap off. This seems to have solved the problem running up statically. No time to road test today. WARNING the coolant comes out very hot.

 

WOW that was the easiest cheapest thing i ever fixed on my `97. Removed hose from water valve and from electric pump, stuck on garden hose from one end then the other. Very little flow at first, more and more gradually for a few minutes until full flow from either direction. Hooked hoses back up, now have plenty of heat for first time in a couple of years. Glorious, just in time for ski season. Thanks guys!!

 

So, is this the connector you undid??

 

Hi Johnnybe60.
That is not where I disconnected. I remember considering it but deciding I'd likely be sorry if I couldn't reconnect. I imagine a special tool would be needed to avoid damaging anything.
Look at post #18 up the page (09-28-2010)...the 2nd photo there has a clarified area to highlight the top of what I believe is the water pump for the heater. As I no longer have the car (sold it a few years ago) I can't double check, but as I recall that is the top of the pump. It has 3 (I think) hoses attached to it. Those are where I disconnected.

Wish I could be more helpful, but it was a while ago and the car is gone now. Best wishes -
Mailshack