Hi,

I'm a newbie here and I hope you can help me with my first query.

I've got a 1999 XJ8 3.2 and the internal cabin temperature gauge is reading very high, today when I went to the car and it was cold the external gauge read 4 degrees while the internal gauge read 31 degress. By rights both should have been the same.

The heater is not blowing very warm even when the car is up to operating temperature and I think this might be linked. Can you help?

Cheers, Richard

 

id have the heater Control Valve checked and the theremostat

 

The "interior" temperature is not reading the temperature of the interior, but rather, the temperature that you wish the climate control to maintain for the interior. So it's not reading the ambient temperature and displaying it like the outside temperature sensor is doing.

That being said, you do seem to have a problem if you are not getting heat when the climate control is set to 31 which is probably near the max setting. I'd try a couple things before throwing parts at it.

Turn the Auto and A/C settings off, set the temperature to max... do you now get warm air? If you are getting some warm air but not hot, then it is probably the heater control valve if your temperature guage is running at the normal.

Search the this forum and see what others have found on this issue, I'm sure you are not the only one that has posted something similar over the course of the last several years.

 

Does your car have an auxiliary water pump for the heater? My 95 xj6 did and all I needed to do was clean it out. This is what it looked like http://www.gusglikas.com/AutoRepXJ6heaterpump.htm

 

I have a weak heat problem too. I will be installing a second hand heater control valve. But I will clean the pump and flush the heater matrix whilst I'm in there.

Thanks for the pics.

 

My heat was weak but when i cleaned it it worked fine. The pump is not connected directly to the motor it is magnetic pump housing. I do understand that the brushes fail on the pump.

 

Hi guys, thanks for the help. I have a spare pump so I might check that although I need to find it!

Will look on Thursday and let you know how I get on.

Cheers, Richard

 

Use this link http://www.gusglikas.com/AutoRepXJ6heaterpump.htm and click on the first two photos and you will see where mine was located.

 

Hi,

Thought I'd give you an update, after much mucking about, and replacing the pump and the valvee it turned out the matrix was full of gunk. Probably from mixing the coolant type at some point.

Ahh well, all nice and warm now

Thanks for the guidance.

 

How did you clean the gunk out of the matrix? After looking at the pump and valve I think I may have the same problem.
I was thinking of using one of those radiator flush liquids to dissolve the scale.

Thanks,

Dan

 

Could you elaborate on where / what the problem was and how it was fixed? It seems that it is not an uncommon problem and providing a solution would benefit many.

 

Hi Dan,

I didn't clean it, I decided to replace it. They were about £70 new and I though maybe all the gunk will never come out and the problem might persist.

There are a few on Ebay for about £35 but I needed one quickly.

Good luck, cheers.

Toasty Rich.

 

Thanks Toasty Rich.
I was afraid you were going to say that. Replacement of the matrix is a bit tricky with all that dash disassembly.
I will forge ahead with a garden hose flush and chemical treatment of the existing matrix.

Dan

 

Good luck Dan,

I'm sorry I didn't have the time to do the same, interested to see how you get on.

Dash disassembly and refit is a 3 hour job on Jag books.

Cheers, Rich.