'05 Mercury Montego -- A/C is ice cold . . . but only when RPMs are elevated!

Hi everyone,

Odd problem I’ve never seen before–I have a fully recharged A/C system in my '05 Montego (aka Ford 500 with a different grille and interior). I took it in because I thought the freon was starting to go. Recharging it did not help. I later realized what was going on: When idling, there is basically no cooling at all, but when I am at speed or in neutral with the pedal down a bit, I get quite cold air.

Any idea why that might be? Thanks a lot!

It’s probably a slipping drive belt or belt tensioner.

Seems pretty simple–I can’t believe the place I took it to didn’t notice that!

Had to have my compressor replaced with an after market one. I had the exact same symptoms. Look under the car (not on the driveway) on the compressor for a leak—Yellow oil.

I would think that yellow oil would be the result of leak detection dye being added. But certainly, if the compressor is leaking oil at the front seal it is on the verge of failing, @Glenn.