Hi. Another issue with the "new" 2000 xk. Heat works but doesn't get very hot. We had been traveling about 200 miles where it started getting a bit cool. Turned up the temperature and it took about 15 for me to even notice the heat was on at all. Been on now for about thirty and it is somewhat warm inside. It is only 58f outside. Any suggestions? Thanks again.

 

Several things can cause the flow of heated coolant into the car. I would suggest checking your thermostat the second would be to check your heater coolant pump. Now you have several other things that you can check like coolant jelling and causing a restriction but these are a path to the others.

 

Here is a link to a pretty extensive bit of information on the XJ Climate Control system compliments of Jim Lombardi. Similar enough for an understanding of the XK system.

https://www.jaguarforums.com/forum/x...nfo-faq-66454/

 

Did you mean "doesn't" get very hot?

In addition to Gus's checklist, the interior temperature sensor can get covered in debris over time and give rise to problems.

This sensor is behind the small plastic grill on the lower dash liner below the steering wheel. The panel has to be removed to clean it out.

 

Check fuse #15, 10 Amps, in the engine compartment fusebox for the heater pump. If it is blown, it may be a sign of a bad heater pump.

 

In my case there were two hoses leading from the firewall to the heater pump that had become kinked and restricted flow. They are beneath the driver's side vanity panel under the hood, hard up against the firewall.

 

One of those hoses is supposed to be kinked!
My car heater would only work at high rpm. It was due to a failed heater pump.
It is hard to see, I think the gearbox has to be dropped to replace it!
Got the dealer to do it, was about 3 hours labour I think.

 

Heater pumps were unreliable when I had an X300 saloon ten years ago. Good to hear my current Jaguar may still suffer the same problem!

That was a very reasonable labour charge if it did involve dropping the box.

 

Always start with the simplest solution first.

Did you make sure it was topped off and that there was no air block?

Sometimes just opening the cap and running the engine will move the air block, or adding fluid.

Just had the same issue with the Land Rover, topped it off and presto, fixed.

good luck,

jj

 

+1 to jamjax 'simple' check. When I had some hoses removed to allow the throttle body to be unbolted, when I put it back together, the expansion tank was empty. I topped it up, capped the tank, and ran the car...with the Heat on full blast, max temp, for about 10 minutes, the hoses to the thermostat tower were REALLY full (one had a little bulging going on) so I 'massaged' the hose, sqeezing it to move the air if there was some at the t-stat. Turned the car off, let it sit, and opened the tank, lots of air to release, thats a good sign. Ran the car again, with the cap back on, heat on max, and uncapped (slowly, in case its under pressure), the radiator hoses were flexible, and no resistance to some squeezing. I could see the coolant being exchanged in the expansion tank, meaning all the air was out, and coolant was moving easily. You can also leave the cap a little loose also, no harm being done, I assure you; it won't be under pressure now, and air will be able to escape as you drive the car and it is moved to the tank. Then after a few days of driving, you can tighten it back up.

 

Whenever I've had a cooling system hose undone and had to top up the expansion tank, I deliberately leave it about half an inch below the normal level and first run the engine until warm with the cap off and A/C set to max to get any air out. Also use the 'massage' described by H2Oboy to move any air. Switch off, top up and replace the cap.

Had plenty of opportunity to practice this technique on my 2001 XK8 which had water pump, thermostat, tower and throttle body replaced at different times.

Not sure Jaguar would approve but it works.

 

I seem to have the opposite heater problem. While jumping onto I20 a couple of days ago, the heater just started blasting full heat unless I turned on AC and cranked all the way down. No in between. I just started to check out everything on the forum, which post if I find the problem myself. I usually have it set at a comfortable 72 F without incident.

Where is tempeture sensor?

 

Attached is the climate control diagnostic document. You can actually get error codes on the climate display with the specific key sequences defined in the document (see page 11).

The system is quite complex, so your problem may or may not be the inside temp. sensor (which is located behind the little approx 1" square grill on the lower dash, behind the steering wheel).

 

Nice! Have you got the '97 version? Couldn't find it in my JTIS.
Thx, Mike

 

It should be there...look under Electrical-Control Components-Diagnosis and Testing or search for '412-04'

 

if the coolant level light is on will there be no heat?

 

Never mind no heat, if the coolant light is on you're approaching serious trouble.

It's a low volume system and this light signifies a near empty expansion tank (or worse a hose gone). Need to stop and investigate immediately.

 

forgot to mention that the level is good. the sensor is acting up.

 

..............so you did stop and investigate

The heat output should still be normal with a faulty level sensor.

 

yeah did... the heat is not working at all i don't know where to start