I,m slowly going through my XJ8(308) and yesterday was fix no heat using heater. I read numerous thread's with I must say good advice in ALL of them. So yesterday I drained the coolant and reverse flushed the heater matrix a good number of times, and left her standing overnight with a flushing agent in. This morning I flush it out numerous times and re-assembled. After filling, bleeding air out etc, the heater did still NOT work!!! So I then removed the heater pump to check the motor brushes etc and after putting back together I reconnected the pump while it was sat on the bulkhead. It didnt work(no noise etc) so i put everything back together and filled the coolant up etc so I could move her while I sourced another pump. THEN I remembered someone saying try altering the temp between max and min numerous times, so thinking what have I got to waste I sat doing it for 15-20 mins, and just as I was going to give up I got FULL heat in the car then I kept repeating time and time again and now heater works just as it should!!!!!!! The moral of this is read ALL threads and suggestions, but try to have a plan of attack using the forum to list the EASIEST ones 1st!!!!! Thanks to you all for your information you share on here, and I will be reading again for my next mission lol

 

It sounds like the hot water gate was corroded into position from either sitting too long that way or its been awhile since the fluid had been changed and caused buildup. The actuator could have setup also (don't know if Jag's is vacuum or electric?) Thus the constant up and down of the temp was getting the actuator and/or gate to break free and allow hot radiator fluid to flow again.

Nice job anyway, simply staying persistent and getting it working.

 

Thanks for your information, and one thing I am is persistent lol