OK, I can see where those vent temps aren't going to cut it - BTDT. You should be getting better performance. I just checked the NOAA website for Phoenix, and although the ambient temp is 103, the dewpoint is 34. That means your ac system doesn't even need to condense water out of the air to make you comfortable. The latent heat of water is very high (hence the reason it makes a great engine coolant), so this represents the removal of a very large heat load from the ac system.

The 10F temp difference between idle and highway is normal on these older cars. The compressor just doesn't have enough output at idle to produce colder air, regardless of how well the evap and condenser are working.

On your data above, was one drive early in the morning and the other with the sun overhead? The difference in vent temps could well be due to the difference in solar load (i.e. infrared heat) the car is absorbing.

How confident are you the recirculate actuator is working correctly? The 124 has 3 recirculate positions - 0% (fresh air), 80%, and 100%. The vacuum actuators - there are two for recirc function - have two seperate vacuum chambers. Applying vacuum to both delivers 100% recirculation. The portion of the actuator that takes it from 80% to 100% seems to fail more frequently. Perhaps you have only partial reciculation? It's easy to check if you have a handheld vacuum pump with a guage.

Finally, how clean is your evaporator? IMHO much of the improvement I saw after replacing everything on my 124 system was because it had a clean evap, where none of the fins were blocked or coated with insulating dust and dirt. Quite simply, the new evap had the ability to absorb much more heat from the airflow over it. These early 124 cars don't have cabin air filters, so the evap tends to get rather crudded up.

Enough rambling for today,


- JimY