The A/C in my 2002 XC70 typically works fine. However, while sitting in line at a drive-thru, or letting the car idle in a parking lot on hot days with the a/c on, my a/c quits working (blows hot air) and usually does not come back on until after shutting the vehicle down. I recently had the evap core temp sensor replaced, but it still occurs. Any ideas what's going on? Thanks.

 

A common problem is the gap on the ac clutch becomes too large from wear and when very hot the gap can't be closed by the magnetic field. The solution is to set the gap on the clutch. Usually that is simply removing most or all of the shims. Monitor you compressor to see if it is still turning when it fails to cool (yes it is hard/impossible to see from above)

 

Thanks. I’ll show to my mechanic.