1989 XJ40 3.6L 130K miles garaged car June 22 2020… that straight 6 engine winds out nice to 5.5K.
MY AC compressor is not working and belt is off pulley. So just fresh air available for now.
I now get only fresh air out the vents mostly from center vent in summer, that all works , nice volume of air blows out center vent but sometimes or most times … the air is warmer than ambient meaning some outside air is leaking past the heater core and out thru the center vent.
Q1_Does this indicate maybe upper blend flap feedback POTENTIOMETER-resistor needs adjustment? or is it normal to have a bit of air leak past the FLAPS through as the core?
Even with a vacuum heater water valve (fairly new replacement part) , car eventually warms up and then park-stop somewhere–car sits—… the vacuum bleeds off and the valve opens up (default with no vacuum on valve is heater valve is OPEN) and thermal siphoning would certainly eventually heat the core up… default valve should have been CLOSED with no vacuum but alas it is not that way.
It is a shame considering the complexity of the system that the AIRCON designers who have probably zero experience repairing anything, did not think to install a PLEXI port or removable plug (called a witness hole in construction industry regarding coupling nuts) inspection hole to see what those “invisible” rotary blend flaps are doing and where they come to rest.
Q2__Is it possible that this is normal blend flap clearance leakage or are those Blend flaps fairly air tight?
Q_3 Anyone try adjusting the feedback POTS?
Yes AC would be nice, our SD509 (no thermal or HI-LOW switch on this original OEM com) comp seized due to low charge, SH7H15 , almost same CC’s displacement, and has same mounting bracket dims and should be a good reasonable cost replacement-just need to pick one of 40 or so back CAPS… thinking GM style 7/8 & 3/4 screw on fittings…
Thanks to all on the AIROCN BradK 1989 XJ6 black and grey