I haven't done this my self on the 504, and my shop manual does not
cover it. From the exploded view in the Haynes manual, it looks like it
slides out of the assy from the hose side. So, hoses and valve control
cable disconnected, the plate unscrewed (4 screws), slide the core out
sideways from the hose side. This seems similar to the 404, which I
have done. One problem of yours is that the AC is an add on, and may be
layered over the rest of the heater system. Sorry, I'm weak on the 504.
Joe
Received on Sun Nov 25 09:10:33 2007
