Manfred

I think the biggest challenge here is that there are so many possible areas where the AC system can fail. The good news is, most of the work can be done with little experience and few tools if you do the research here on the forum. There's really good write ups available on checking the vacuum system for the HVAC (including the solenoids) and also for the electrical system for which Wally is a great resource. It will take some time to go through the whole system--you're very likely to have multiple problems. I had a hot AC that did better after a recharge. After going through my whole system though I found bad solenoids, bad diaphragms, and a bad heater valve in additional to multiple leaks. Along the way I cleaned the condenser to help the system work more efficiently. Even with all that I think I still have some leaks that need to be addressed. I like the approach that if the compressor kicks in when the turn on the AC (look under the hood to see the pulley engage when someone in the car pushes the AC button). If you compressor is working then recharge your system and see if that fixes your problem. It will at least be better while you find time to go through the whole system.

Dan

Alan

Agree with Theo - there are other failure mechanisms to consider. Certainly start with the refrigerant circuit and make sure that is working well. If the results still aren't up to snuff - start checking the general vacuum system, hot water valve and comb flap to make sure these are working properly - all of these affect AC perfomance significantly...

Alan

mpesik

Hi Malcolm. If it's the weekend coming up my boy and I are going to Calgary.
BUT if it's the weekend after I think we can hook up, say on a Saturday night after I have to take my Son back ?

mpesik

So far..compressor kicks in, fans go on.
The air that comes out the vents is cooler by a few degrees than the outside air temperature.
It is cool- BUT- not cold.
I don't believe there is a leak because the cool (somewhat) air temp. coming out of the vents hasn't changed since I got the car.
Am I wrong to say this ?

WallyP

If you really want to know what is going on, you will have to put a set of gauges on the system and see what the pressures are. That is the basic starting point.

blown 87

A good field test is to feel both lines going into the front expansion valve, little line hot, big line cold, wire the heater valve shut and get kind of cool most times.

docmirror

Yes, to the above. Block off the heater hose by putting a large ball bearing or marble in it then reattach. That way, it doesn't matter if your heater valve is open partially or not. Next, remove the thin plastic overlay in back of the fire wall. Then you expose the blower, and the rubber duct leading to the evaporator. Pinch that rubber duct out of the way, and clean the front side of the evaporator of leaves, butts, bugs, and other junk so you get more air flow. Drive the car, don't just sit still and use a thermometer in the center vent to measure the temp so you have a baseline. Then put the gauges on the system and make sure there's lots of airflow across the front of the car with an extra fan.

Report the gauge readings and we'll go from there. Sounds like your relay in the AC head is working as expected, but you're not getting a full temp exchange yet through the evap.

<edit: One more thing. If you look under and behind the glove box, you will see the recirculating register behind the black grill. When the AC is on, and on the max setting, that flap should be in the up position, blocking off outside air, and using the recirculating air from within the car. This can make a huge difference in temp drop as the outside air is also more humid. If that flap isn't all the way up, find a small stick, and brace it up until you get the vac solenoid that actuates it repaired. I've had mine blocked in the recirc position for a while. When it gets to fall, take the stick out, and let the flap close, thus letting in outside air again. AC should always be in recirc mode.>

Podguy

Gee I am surprised no one mentioned looking in the site glass on the dryer. It is the quickest way to check if the system is low on Freon. If you see bubbles then the Freon is low. The most common cause of leaks in A/C systems is the front seal on the compressor.

Harbor Freight has a good deal on gauges and a vacuum pump. You will need an adapter to make the R134 gauges and pump they sell work with R12. The adapters are available on the internet - just do a search. R12 is generally available on Craig's list.

The other thing I have found that makes a big difference is sealing the cabin. On my 85 the A/C on high still did not cool the car. I sealed the fire wall leaks and air coming up from the shifter and the car is
cold on low - so much so I need to keep cycling it off and on to stay comfortable. I used spray foam for this from the hardware store. Just be careful not to put too much in.