Hi all,

I know how annoying it is when a new member on a forum instantly comes around the corner with a problem... Forgive me for that, please.

"Winter" kicked in quite early this year, and I'm freezing! Even with a (very) hot engine, no hot air will be blown into the interior. This summer I experienced not problems at all: I even filled the AC and after that it worked / cooled like a charm. It even manages to control temperature.

I have already tried to put the interior temperature to it's highest and lowest setting some times (as suggested somewhere), but that did not work. As said, I don't think it's something like a thermostat (because the interior temperature is just ok AC is working perfect in summer: getting the temperature down and keeping it there is not problem). It's not the fan(s) either, it also switches to floor / front window / face without any problem.

I have got the feeling that somehow, hot air (generated by the engine) is not mixed up properly with cool air from outside. Is there a valve somewhere, which I can check? Where to look for it? What should it do? If I want to solvo this problem myself (I have got two left hands, but also a jack and (usually) a functioning brain), how can I diagnose and solve this problem?

Thanks in advance,

A freezing jaguar enthusiast.

 

Well the first thing we need to know is what year and model are you working with. It would help if you go to the user control panel and add the vehicle info to your signature and then it will always be there.
You said that you set the red arrow to hi and got no heat. Correct?
Knowing what vehicle will help us advise.

 

Sorry, it's a 1999 XJR x308. Yes temp all the way up and no heat (at all)!

 

Probably the heater pump or heater matrix control valve.

Could be a clogged matrix and I have used chemical flushing on some cars when I worked at the dealer.

Here is a TSB we used when I worked there.

bob

 

+1 try a flush first.

 

Like motorman suggested right? That would be a first for me but ill try!

Thanks for the advice.

 

Yes check this out.

https://www.jaguarforums.com/forum/x...03/#post833113

 

Thanks for all replies.

Is this the drain I have to unscrew?


And which hose is to be disconnected?



And last but not least: where does the clamp g0 (as described in TSB?



Thank you again in advance. All help is greatly appreciated!

 

Maybe the clamp has to go on one of the hoses on this picture?

 

Hi Pancake,

Did you read this section of the TSB? In your photos your air filter cover and intake hose are still in place....





In addition to cleaning your heater core with a chemical flush, I would recommend draining and flushing your entire cooling system and replacing your thermostat. A common problem is owners not changing the coolant often enough (or ever), or worse, topping up the coolant with the wrong antifreeze. Mixing the wrong coolants can lead to the formation of a gel that clogs the heater core and sometimes even the radiator.

Depending on the VIN of your 1999 X308, it was originally filled with either D542 (Dow 542, which was yellow and is no longer available), or JLM20972 (Ford Motorcraft WSS M97B44-D, which is orange). The orange coolant is of the Organic Acid Technology (OAT) type. Cars originally filled with the yellow coolant were often subsequently converted to the orange OAT after completely flushing all of the old yellow stuff out. Adding an incorrect coolant such as conventional green ethylene glycol or a Hybrid Organic Acid Technology coolant like Zerex G-05 (which was often mistakenly thought to be the same as the old D542) can lead to gel formation, shortening of the life of the corrosion inhibitors, and other problems.

Unless you know the full history of your cooling system, the best approach is to flush it completely, chemically clean the heater core, replace the thermostat, then refill with the proper 50/50 mix of orange OAT and distilled water. The most commonly-available version of the orange OAT coolant is Prestone Dex-Cool, available at most auto parts stores, Walmart, etc.

Cheers,

Don

 

I have an XJ so only removed a rear engine compartiment cover.

In my system there is currently some lime green stuff!

 

Sorry pancake,

I misread your vehicle details in your earlier post. It's helpful if you add this info to your signature line so it appears in all of your posts. To do so, go to your User Control Panel and select Edit Signature in the menu on the left.

Cheers,

Don

 

I just purchased another 2000 red VDP and the heater was not working. I removed and replaced the connectors on the heater valve and the heater motor and removed and reinstalled the heater relay. The heater has been working ever since.
I also have another red 2000 VDP that there was not much heat even at the highest setting. I ended up having to disconnect the hoses to the heater core and flushed it out. It works fine now. Another thing to look at, once the car is running for a few minutes, the temperature gauge should read in the middle of the dial. If it is only about 1/3 the way up, the thermostat need to be changed.
Best, Dave

 

Thanks a lot.

One of my "challenges" right now is still that I don 't know where the heater core is and which hoses to take off in order to flush. Can anyone help me with that? By the way: engine temp is right in the middle!

 

Hi Pancake,

Once again, it is helpful for you to add the year, model and engine details of your Jaguar to your signature so this information appears in all of your posts so others don't have to search through previous posts before they can provide accurate replies.

I assume your 1999 XJR heater setup is similar to our 2003 XJ8. The heater core is inside the dash panel behind the center climate control panel. The pipes that feed hot coolant to the heater core pass through the firewall/bulkhead to the left of the center of the car, approximately in front of the steering wheel on a left-hand drive car, and just below the windshield wiper motor. On the engine side of the firewall, one rubber hose connects a heater core pipe to the water valve, mounted below the coolant reservoir, and another hose leads to the electric water pump that the Jaguar parts diagram calls the "Air conditioning water pump," which is mounted on the left inner fender below the brake master cylinder. Here's a link to a diagram that shows some of these parts, though it doesn't help with their locations:

X308 Water Valve, Pump and Hoses 1998-2003

Cheers,

Don