New purchase - AC question
 

Going to look at a 1998 Boxster. The AC has been described this way: System pressure checked and good. Blows cold when the car is cold (start up), then cool but not cold when the car is warmed up. Approx 20 degrees below ambient.

I'll check the fans in front of the wheels to make sure they turn on. Could this be the common foam failure? If so does that repair require removing the dash? Anything else to look at?

I'm gonna guess foam also. But, you really need gauges on the system to tell if it is properly charged. And the freon should be removed and weighed back in to do it to spec. Having said that, I realize most people just dump gas into a system and get the charge close.

There is a hack for repairing the missing foam that doesn't require removing the dash. Search should bring it up. Short version is you pull the radio and center controls and cut down into the blower housing. This exposes the blend door. You use aluminum tape to replace the foam and tape it all back together. I fear this project is in my near future also.

This is definitely caused by missing foam on the heater core flap. The AC is cold at cold startup because the heater core isn't hot yet. As the engine and coolant heat up, the AC is now blowing over a hot heater core.

This is a relatively easy fix.

https://986forum.com/forums/performance-technical-chat/42802-interior-vent-debris-3.html

There are a couple of big chunks of foam in the passenger vent. The problem is potentially much larger. There is no cool. It's plain warm all the time. Fans turn on. The compressor doesn't kick on.

The car was nice enough that I bought it anyway. I sold a 944 about 18 months ago so it's good to have a new Porsche to play with.

I vacuumed the system and started to add freon and the compressor didn't turn on. Time to start troubleshooting.

Check AC clutch circuit to see if it even gets a signal to engage the compressor.