Going to do a heater core flush due to very very low heat output at any RPM... which pipe to the heater core is the inlet, and which is the outlet? I know to flush from outlet to inlet, but I can't tell which is which. :-)

 

See the attached pdf. It is taken from the 2nd edition (1999) workshop manual, but it is the same.

Check out also this post from fmertz:
https://www.jaguarforums.com/forum/x...2/#post2118558

 

Once I got the little black plastic coolant fill tank and its bracket out of the way it was a lot easier to see what was going on, and the pipe on the right was clearly connected to the heater pump (so that was the heater core inlet, and the one on the left was the heater core outlet.) I flushed it backwards, forwards, backwards, forwards, then backwards, at which point it was allowing a healthy stream of water through. Put it all back together and now I have heat, just in time for top-down-heater-on driving season in Arizona! :-)

 

Well done....