A great deal has been written about diagnosing a no heat situation in XK8s and other Jags. I have read these posts with interest, and they have been a great help. Popular wisdom is that if there is no heat at all, the problem is likely the valve, if there is some heat, the problem is likely the pump. My experience adds a slightly new twist on this assertion.

Based upon that good advice -- and with no heat whatsoever in my car -- I ordered a valve from ebay for $45.00. I removed and inspected both the valve and pump and found the valve operating, but the pump frozen. I disassembled and cleaned the pump, which then operated.

Afterwards, I decided to flush out the heater core with a garden hose. Much to my surprise, I could not get water to flow through the core -- either way. I then removed the check valve and discovered it, too, like the pump, had fallen victim to the deposits and buildup in the cooling system. I cleared it and cleaned, then reassembled.

It works! I have heat.

Suggestions for all:

1. Disassemble and inspect before buying parts.
2. Check both of the one-way check valves in the system when servicing.

By the way, I invested 9 hours in this project, and only spent about $100, including fresh coolant.


Hope this is helpful to someone.



Best,



Martin