Hi everybody,

I’m a reader of this forum for a long time. Il has helped me lots or Times.
I’m living in France, and have my Jag since 2011.

This car ask en very special relationship with mecanic ;-)

Today i need your help because i have a heating issue.

First of all my car il a X300, year 1996 sovereign. Blue and beautifull !

My heating system used to work. Now it doesn’t and the winter is coming !

My gauge is on « N », it mean the température of the coolant is ok.
The air is blowing it work good but it is cold.

When i drive over 130 KM/H the air is hot. Not very hot just a little, but enought to be on 20° Approx.

I saw this week that the temperature is hot when the air is comming on the face. Not in the foots no more on the front glass (i don’t know the english word sorry ;p)

Sometimes the driver side air is hot but not the passenger side ...

My car does what it want in fact !!!

Can you help me for the diagnostic if possible with photos because i don’t know the heating system...

I’m sorry for my approximate english. I do my best
Thx all.
Vince.

 

The X300 has 2 water pumps to circulate the engine producing heated water . The main mechanical driven one for the engine radiator and a second electric one to run some of this hot water to the cabin heater core or matrix . Under certain conditions of engine operations the failed second pump called heater pump can be overridden ( in a fluid sense ) and put some hot water in the cabin heater core or matrix which is what you are feeling . This electric pump is located on the rear left side of the engine compartment and you can put your hand on it and feel it as a troubleshooting tool . It is hidden under the square plastic air chamber the extends aft from the engine air inlet as it make the 90 degree turn into the engine

Fuses : Left Engine Bay fuse box # 8 - 15 amp and RH Heelboard fuse box #16 - 10 amp

You can tap on this electric motor and relay with a wooden stick or back of a large screwdriver as you have the heating system turned on (and engine warmed up enough ) and make it work in a temporary fix

No need to replace the pump as a whole unit for the motors electric brushes wear out and can be replaced very cheaply and by yourself

.15" x .15" x .35" BRUSH 33A

Keep in mind you are dealing with dangerously hot water .

If you take the pump or impeller off of the electric motor the large o - ring will have swelled and won't go back on so plan ahead , the o - rings are common at the hardware store

Check the fuses first then swap the heater pump relay with the fog light relay . Spray the relays housing with some penetrating oil first as they get stuck . Look for 12 volts between the 2 sockets of the motors pigtail connector

Jaguar XJ6; Jaguar X300; Heater Pump

Editing : Getting you a actual picture of the items of interest

 

Waouh ! Many thanks. What an answer complète and clear !
So. I checked somes things as you said.
The secondary pump doesn’t work. The fuse seems to be ok.

I didn’t cheked the 12v. Don’t have the tool ...
BUT the brushes are about 1 mm each and one of them lost his electric wire. I think it can be the problem. I ordered 2 brushes on Internet. Waiting for them now.

I will try this.

Thank you again for your help and the pictures wich helped me.

 

had the same problem,changed thermostat,problem solved,steve

 

Once you have repaired your secondary pump and reinstalled it, it would be worth running through the heating system diagnostic check. This can be done from inside the car, without any tools, simply by pushing the correct sequence of buttons on the heating controls. It reports on the operation of the syatem, including the various air distribution flaps. I cant remember the sequence off hand, but if you google it, you will also get a list of error codes and their meaning.
I am pretty sure the repaired pump will fix your problem, but the diagnostic only takes a couple of minutes.

 

Self Test

 

Thanks all.
I’m waiting for the brushes i hope this week end it will be done.
I’ll do the test after.
I’ll tell you if it work ☺️

 

I received and changed the brushes yesterday evening.
This morning i tried the car and the heating is working good !!!
many thanks to all for your answers. It was very helpfull.
regards
Vince.

 

Hi, everybody!
I wont make a new topic for my Jags heating problem, so I will write here.
Mystical problems with hot air.
Temperature usually stays on N, in the city or while driving on the highway.
I have changed mechanical pump and that electric one, and air in the system shouldnt be.
So, while Im driving in the city, it blows hot air, not very hot, but +/- normal. In winter, when outside temp is under -20 for heat in the car I can forget.
When Im driwing on highway it blows only a little bit warm air or cold air, but engines temperature is shown N, thats why I dont think its thermostat fault.
If outside temperature is -10*C, on highway warm air is impossible.
Today outside is 4*C, Im driving it on highway, it blows only slightly warm air, womens would say its cold air, when temp is switched on HI. When I press the button to take air from Inside, it starts to blow a little bit warmer, but on windows moisture builds up quickly and air itself feels wery humid. Heater core should be ok, because when car is taking air from outside everything is fine, only on highway blows cold air.
Heater diagnostics show one error with A/C pressure, so nothing to see there.
I would understand if the cars engine temperature on highway driwing on 100km/h would not be N, but it would cool down, then ok it could blow cold air, freezing or whatever, but if engine temp is N, pumps are ok, coolant level ok, thermosts seems to be ok.. I just cant imagine what else could be wrong.

 

IF all that stuff is fine, then your heater core is clogged and needs to be flushed.

 

Could be, but if its clogged, then there should be problems with heat while driving in the city. Maybe I should try to change thermostat, but that damn temperature stays N all the time.

 

Hi i started having very similar problem with heating, except in my case the heater doesn't work at all. Regardless city driving or highway driving. I suspect heating pump in my case.

I would suggest you to take a look at the heater control valve. This could be the case, as you said that pump is working.

I will do my repairs this weekend - will remove the pump, change the brushes, check the valve operating.
Will keep you informed about my efforts.

 

Dissasembled my pump, replaced the brushes. Pump seems to be working ok.
The brushes were to big so i sanded them with sandpaper to proper size. Couldn't get them perfectly ideal in size and shape, but it looks to be not do important in the matter of proper functioning.

 

Did the same thing but is finishing the job to see if the pump was really the problem. I'm pretty sure the pump is the problem since one of the brushes were completely wear out and the other one almost the same.
While working on the system, decided to take the chance to flush the heater matrix core but it seamed ok while doing it so.
Also changed the thermostat because temperature was dropping too much while on any road and I can't find another reason for that at the moment (The thermostat seamed to be the most reasonable reason I could find).The old thermostat seems to be working (tested on my kitchen with boiling water) but it might be working but not as it should be, so I decided to change it.
Let's see if I can get some heat inside soon...
Thanks everybody for the help and for the photos and diagrams. Without them it would be imposible to work!

 

Check the little "aspirator" which is located behind a little plastic grill in the dash knee roll. A little fan draws air over a thermocouple to determine what the cabin temperature is, based on which the syatem determines whether heat is required. It gets covered in fluff and dust, and effectively insulates itself over time, which can result in an otherwise functional heating system not delivering the desired result. A 5 minute job, from inside the car.

 

Countyjag is correct both of my fans on my cars had never been cleaned, they get quite dirty.

 

Inside Temp sensor with fan .

 

Thanks for the tip, but where exactly is this little "aspirator"? Dash knee roll where exactly, can you send me a photo so I can locate the spot?...
Just finish my repairs and ?i-m ready to test my reconditioned pump tomorrow. Going to clean everything and check the heat valve also before relocate everything in place again.
Keep you posted on my progress...
Tks!

 

Under here , look for the little grill

 

Hi Guys! Wish a Happy New Year to all of you ...
I'm having problems with my eletric pump... Did anyone had any problems apart from the brushes? Changed my but the pump don't seem to working... It just won't work.
Any suggestions aside from open it all to check the internal circuit?
Thanks!