No cabin heat in XJ8

(Mark Gordon) #1

My 2002 VDP takes forever to start putting out luke warm air even after the temperature gauge shows normal operating temperature of the engine. It takes about 30 minutes of driving at highway speeds for the interior to reach a comfortable temperature of around 70 deg. F. even with the controls set to “HI”. I seem to recall reading that the coolant flow to the heater core is forced by a separate electric water pump. Is this correct and if so, is a failure of that pump likely to be the cause of the poor cabin air heating? And is there a test for determining whether that pump, if it does exist, has failed?

(Neil Bennett. Patron) #2

It probably is the brushes inthe Aux heater pump have worn and need replacing. Lots in the Archives it’s the same for both X300 & 308.

You don’t need to drain the coolant as you only loose about an eggcup full.
You’ll need to file the replacement brishes to size, the whole job took me about 1.5 hours to complete.

(Mark Gordon) #3

Thanks, Neil. I usually don’t do the work myself on my daily driver because I don’t want to run into trouble and then be without it for an extended time. However, this looks like it might be something that I can tackle if the weather is decent. (My E Type takes up one side of the garage, worthless junk occupies the other.)

(Neil Bennett. Patron) #4

If you connect the hose from the block to the solenoid valve bypassing the pump you can still drive the car.

(Mark Gordon) #5

Worth a try. I’ll certainly not have any loss of cabin heat since I don’t have any now.

(Mark Gordon) #6

Neil, I’ve been trying to source a replacement pump but the best I can find is a new one from Jaguar for over $500. From reading your comments and the link that you provided, it looks like a pretty simple job to overhaul my pump with new brushes. The instructions in your link call for 4x4x8 mm brushes. It looks like these would work if shortened to 8 mm. What do you think?

(Neil Bennett. Patron) #7

Should be fine give ita go!

(Mark Gordon) #8

For $4.40 vs. $500 it seems like a winner. Amazon gives me a delivery date of Jan.7-29th, but it will probably come sooner than that. I’m going to try to find some locally because it’s not much fun driving with no heat.

(Neil Bennett. Patron) #9

If you have a Model shop near you it’s worth trying there too.

(Mark Gordon) #10

I found an electric motor supply/repair shop not too far from me. I think that they’ll have what I want. They aren’t open on weekends so I may not be able to stop by until next Monday. Thanks so much for your help, Neil. I’ll report back when I know more.

(Mark Gordon) #11

I tried but no luck. The brushes that I ordered arrived on 12/31. We finally got a decent day today so I had a go at trying to replace the brushes myself. After much trouble and use of some new swear words, I finally got the motor out (why do manufacturers make stuff so hard to get at?) and the motor housing off of the motor. It does look like the problem is the brushes; they’re worn down to the connecting wire. Unfortunately, I couldn’t see how to get the old ones out so rather than screw something up and ruin the motor, I decided to put it back together and take the darned thing to the motor repair shop here locally. I’ll need to get some 3/4" tubing to connect the coolant lines while the motor is out for repairs, but that shouldn’t be too tough. I just hope the repair shop can do the job. Try as I might, I’ve been unable to source a rebuilt or even used motor. Again, thanks for your advice, Neil.

(Neil Bennett. Patron) #12

The hose going to the pump will just stretch to the valve if you are lucky, just take the one to the valve inlet off.

(Mark Gordon) #13

After putting the heater motor back in and connecting everything back up, “Low Coolant” warning light has come on even though the expansion tank is full. I can’t imagine that there’s air in the system but could that be causing that warning light to come on? Any other ideas?

(Art Ford) #14

My X308 often gives me that “Low Coolant” read out but it goes away quickly. I was told it is from an air pocket somewhere else- maybe around the thermostat housing. It always goes out after a few minutes of driving.

(Mark Gordon) #15

That’s what I was hoping, Art, but I’ve driven it about 50 miles to and from work the past two days and it’s remained on. I think that this car hates me.

(larry2236) #16

Try Eurton Electric. Part #33A Brush size .15x.15x.35 . I think their in California. I don’t have any more info with me. I used these brushes on my 95 VDP & it worked great

(Mark Gordon) #17

Thanks, Larry. I ordered a set online (See my earlier posting) but once I got the motor out, I couldn’t see how to remove the old ones and was afraid that I’d ruin the motor in trying. I’m going to turn it over to the pro’s.

(Neil Bennett. Patron) #18

You have to CAREFULY bend the brass retaining flanges upand then back down, if one breaks you have to solder it back in place.

(Mark Gordon) #19

I thought that I need to post a wrap-up reply to the cabin heat problem. I decided to turn the problem over to someone who knew what the hell they were doing. A wise move as it turned out. It seems that the motor for circulating the coolant to the heater core was, indeed, working even though the brushes are badly worn. The problem lies somewhere in the electrical sensing and/or transmitting system. The mechanics jumped the power to the motor and it came on.
Ever since I’ve owned the car, about 5 years now, it has had an annoying vibration that seemed to me to be in the drive chain. I replaced worn tires, worn shocks, and had u-joints checked. No joy. Today, they found that the mountings and the cage that holds the differential are badly rusted. Total bill to fix the problems (vibration, cabin heat, cracked plastic coolant distribution pipe) would have run somewhere in the $4-5000 range. In my tenure, I’ve replaced the tires, shocks, fuel pump, power steering pump, throttle body and position sensor and transmission. I’ve put far more into this car than it’s worth as a 175,000 mile car. I’ve decided to cut my losses and get rid of it, even though I really like the car, rather than put that money into it and find out that now that everything else has been fixed, the engine needs an overhaul or whatever major expense it is hiding from me. I’m still a die-hard Jag Lover and will continue to feed my addiction with my E. Man, I’ve never been a quitter and I hate to admit defeat!

(Eliot Brenner) #20

Mark: I was just wandering through Jag-Lovers on my quarterly stroll through the X300 material and came across your struggle with the aux heater pump and subsequent decision to cut your losses. I fought the heater pump battle successfully once with a brush replacement. My condolences, so to speak, on the final outcome. I suspect it will be easy to find something else to take its place. I just dumped $3,300 into my ‘06 VDP (pads, rotors and rear calipers, battery and the dreaded front air shocks) so this thing better give me a bunch more miles. I’m not in the mood for anything else to go wrong! If you’re looking in the X350 department, I might suggest looking for one on which the shocks have been converted to standard. In retrospect, I probably should have gone that route, but I tend to like keeping the car original. Cheers.