i went to buy a new Heater Control Valve today and was told by the my supplier that the new direct replacement ones leak. His explanation was that Tata are now sourcing a lot of parts on the cheap and that this particular item in made in somewhere over in the States and that they sweat around the collars.

Has anyone had any experience of his, and is there more than one manufacturer for this item.

Pretty sure the MTC HVAC Heater Control Valve 653 26003 673 is the one the is referring to.

This is visually the same as the one I have removed and is different from the one shown in the parts manual (the bracket is shown separate)

If the system was properly bled, would I expect this to be full of water when cold?

 

I am having an issue with my HCV also. On my 85' I replaced it with a EBAY part and for 3 years, until I sold it, I never had another issue with it. Not sure what manufacturer because all my paperwork went with the car. The part is a valve just like it says. The bell part of it is a vacuum actuation solenoid and the to ports are in and out with the valve restricting in the middle.THE PROBLEM WITH MOST IS THE VACUUM WON'T MOVE THE RUSTED VALVE. I intend to buy the model your referring to off Ebay again and within the next couple weeks I'll let you know how it works out.

 

This is the part for a 85' XJS. The part number you have is NOT the right one,

New Heater Control Valve for Jaguar Vanden Plas XJ12 XJS C 41051 | eBay