Xjr heaters not getting hot

[hoppo4.2]

As above really. It makes no difference what you set the temp to is just blows cold any ideas?

[king arthur]

What model / year?

[Ecurie Ecosse]

Heater pump perhaps?

[hoppo4.2]

Sorry it's a 98 xjr v8.

[Jaguar steve]

Heater pump is the usual suspect. With the engine hot and idling feel the pump - left hand rear of the engine compartment, it's the black cylindrical component with one visible pipe - to see if you can feel it running.

Give it a couple of sharp taps with a hammer and feel again

If you do have some cabin heat at higher engine RPM then that usually confirms the heater pump is FUBARD as the engine water pump will circulate some coolant through the heater matrix at higher speeds.

[hoppo4.2]

Thanks I'll take a look later on.

[a8hex]

Does the engine come up to temperature?
When the thermostat on my X300 died the heater would also stay ice cold. But then so would the engine.
Even if I warmed it on the pre-heater (an essential option) the temperature gauge would be off the bottom by the top of my road, which is less than 100 yards away.
No idea whether V8s behave the same.

[Piersman2]

It'll most likely be the heater pump solonoid.

The XJ controls the flow of hot water into the cabin heater matrix with a solonoid controlled valve either on , in or beside the pump positioned in the engine bay near the expansion tank IIRC.

I remember having to strip my solonoid to bits to check and free it's operation when I had my 1998 XJR. But that was 6 years ago so my memory may be a bit rusty.

Once I'd had it all to bits, greased and manually operated it a few times it was fine.

Alternatively just buy a new one and stick it in.

[Cecil]

I had this, the alarm sounder was blowing its fuse, it is the same fuse as the circulation pump, disconnected the alarm sounder and replaced the fuse and all was well, sorry cant remember which fuse, but was one of the ones near the passenger headlight.