Well my 1974 xke is running fine. As I drive it I am finding out all the little niggles that aggravate me. Now my heater valve is not shutting off the coolant to the heater core and in Texas that is hot. It seems to be closing all of the way but both the heater valve and the air valve seem to be letting hot air in the car. I put a piece of plastic over the inlet and that helps but is unacceptable as I need to fix it. I am open to suggestions as the owners manual mention a capillary tube which I am pretty sure I do not have. I have adjusted everything and do not understand how hot water is getting past the valve.

Has anyone run into this problem?

 

There is a capillary tube on the heater valve so possible you just have a bad valve. The good news is they're easy to replace and only cost about $100 from the usual sources.

Unfortunately unless you're moving cool air without having A/C is hard to come by on these cars due to the fact that most all of the HVAC ducting runs through the engine compartment. The ducts and heater air box themselves get warm so by the time the air gets to you it's been warmed up. Not much you can do about it.

 

I added a shut off valve at the back of the engine behind the carbs before the hot fluid goes through the bulkhead. leave it turned off all summer and only open it up for late fall or early spring driving. That way I'm sure the heat is turned off.

 

I’m sure you know that in the series 3 cars the lever on the dash must be pulled “out”/“up” to shut off the valve while “in/seated” it is open. I loosened my cable under the heater valve cover and manually closed it as I don’t like driving around with the lever out, why Jaguar designed it that way is beyond me.

 

Ah. Yes the odd decision to have the heater valve open in the stowed lever and closed when the lever is pulled out. That notion offends my sense of order.so I made a lever that I placed on the heater valve to reverse the motion. I'll attach a picture, but I don't have one with the valve cover off. In any case on my car the lever operation is reversed and the lever is safely stowed when the valve is closed. One must pull to introduce heat. Much better.