No heat at all from either side. Tested recirculation motor and solenoid valve at the top left rear of the engine compartment and they were ok. Valve is normally open so if you test the signal with the heater on you will get around 5V which is solenoid off. That’s what the signal floats to when it’s disconnected. Temperature is controlled by the solenoid valve variable duty cycle.

Did a back flush of the heater core (into top front solenoid hose and out the recirc motor outer tangential hose connection} and a bunch of whitish junk came out. Hoping it’s not aluminum oxide but it prolly was. Heater is now working properly.

System had (and still does) the green stuff but I think Jaguar now recommends yellow (not sure if that’s OAT or HOAT). I think the problem is that here in SoCal I don’t use the heater that much.

Hope this info helps somebody.

 

I'll be checking the motor and valve on my car, as I think one or the other is faulty. The pumps are known to fail with age. If they test good I'll do a back flush. I can see how crud would cut the flow of coolant and give the impression of a bad motor or valve. True about the valve being normally open when off, I don't care for that characteristic because it makes the dash air warmer after a trip, upon restarting.