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A/C 5k

Ted writes
>Well, after stumbling around the 5k today looking at the A/C, I found a 
>few things. Well, actually just one: the thin copper pipe on the 
>passenger side of the A/C compartment is COLD. I mean-- really cold-- so 
>this seems to rule out a few things. I think. 

I don't know exactly what the year or configuration your car is but in
general here are the rules.

A liquid line runs from the receiver/dryer to the expansion valve which is
located usually right where the smaller of the two refrigerant pipes go
through the firewall on the passenger side. When the compressor is running
this liquid line should be warm to hot. The pipe on the other side of the
expansion valve (going to the evaporator core in the passenger compartment)
should be very cold. The second pipe which is larger and comes out of the
passenger compartment and goes to the compressor should also be very cold.

Since at least one pipe is cold, the compressor is running and the system is
not completely out of refrigerant.

If the pipe from the evaporator to the compressor is not cold, the
refrigerant charge is low and this is why you get no cooling. Low charge is
responsible for poor cooling 99% of the time. If this is the case the system
should be leak checked and if a leak is found, the refrigerant should be
recovered, the leak repaired and the system recharged. If no leak is found
and the system has just lost charge slowly over the years it can be topped
up. You must be certified to legally handle R12 and R134a automotive
refrigerants in the U.S.

If the refrigeration system is ok and you get air out of the panel vents ok,
I can't believe that the temperature door is in the wrong position or you
would get heat out the vents.


Bob Cummings
87 Coupe GT