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Overheat and A/C Compressor?

Discussion in 'Chevy Trucks' started by Q101ATFD, Dec 2, 2007.

  1. Q101ATFD

    Q101ATFD Senior Member
    Messages: 277

    Transported my plow today on the 2005 2500HD about 15 miles no faster than 40mph. It was raining and super humid out so I had the defroster (A/C) on, but all the sudden the A/C compressor cut off and I couldn't see out the windshield. Immediately checked the engine temp and it was 230º - a little hot, but not in the red zone.

    I had it in 3rd gear while going down a shallow grade (but somewhat long) hill to help the brakes before the compressor cut out. I was only going around 35mph at that time, and RPMs were under 2200. A couple miles down the road (flat at this time) I found a place to pull over and check things out, I shifted it back to 4th the A/C kicked right back on.

    Anybody had this happen to them? Will the engine shut off the A/C compressor to keep the engine cool - even though the temp didn't go any higher than about 230º?
  2. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    What actually happened is the high pressure switch in the A/C system cut the compressor off due to it seeing elevated high side system pressure..

    The high pressure in the A/C system was more than likely due to the plow restricting airflow through the A/C condenser.. if the condenser can't expel the heat out of the refrigerant enough, the high side pressure will climb quick..and the pressure switch will cut the compressor off to protect the system. It did exactly what it was designed to do...

    It's the kinda the same example as some guys see with engine temps climbing with a plow on, except in this instance it was the A/C system that experienced the "overheat".
  3. Q101ATFD

    Q101ATFD Senior Member
    Messages: 277

    Wow - I guess you learn something new every day. Is the condenser up front with the radiator? Could I be experiencing the fan clutch issues, but with a different outcome? We're going to have issues though if this happens throughout the season :eek:

    I'm going to just hope that it happened because it was 55º*outside...
    Last edited: Dec 2, 2007
  4. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    I know I always try to..:)
    Absolutely, and I'm surprised more guys don't experience the same issue more often...

    If I was to take an educated guess, I'd say your truck doesn't have the Plow Prep fan clutch on it..