Hi all.... again, I'm new to owning a real car... I have a 2000 XJ8. with winter coming way too soon for me, I turned on the heater yesterday to make sure it worked and sure enough, no heat! So, wheres the best place to start checking? I really don't want to just start replacing parts without some clue. The coolant is right up to the neck, the AC works great.
Thanks so much

 

The first step is to set the temp control to HI that will be max heat. Then see if you are getting heat. If you are then press the button for EXT temp. Is it reading close to the actual outside temp.
I couldn't get heat because the external temp sensor showed it was a 132 degrees outside and wouldn't give heat.
Try that and get back to us.

 

Another thing to check - do you have ANY heat at all? max temp, low speed, hi speed, etc? I had an issue with no heat prior, and it was the auxiliary pump located on the drivers side (US) inner fender well, near the brake booster. Usually the brushes will wear out and the motor gives up. Coolant will pass through to keep the engine from overheating, but won't flow properly to diver to the heater core and all that jazz. You can either repair the brushes, or just replace the unit - I opted for replacing with the intent of repairing the original but never bothered since it hasn't acted up in the last 50k miles. Replacing it with another known good unit takes about 10-15 minutes, and CAN be done without removing the coolant expansion tank, just takes some fiddling.

That's if that's what the problem ends up being, of course. I think I spent 40 bucks or so when I got mine used on e-bay? Been a while. I believe it's the same pump that the intercooler pump is for the SC cars, which can be replaced with a nice Bosch unit with a wiring splice, so that might be another option too - though the Bosch is thicker around so the bracket might need help.

 

Thanks very much.. I just checked the hose going into the pump. The pump is hot and one hose is hot but the other hose is cool. I've got no heat on any fan speed. I think it's the pump.... ???

 

You mean it really wasn't 132 in Vegas Vern?

 

Sounds like the heater pump, the brushes in the pump wear out and the pump quits. I was able to replace the brushes on the pump in my XJ8 and solve the issue. Here is the brushes I used. .15" x .15" x .35" BRUSH 33A

 

. Today I replaced the water pump for the heater. Topped off the antifreeze and drive the car. Still no heat... Seems like all the hoses are hot but I don't think it's going into the heater core. I'm not real sure about that. What could I be missing?

 

Surprisingly it never reaches a 100 in December LOL.

 

LMAO!!