AC clutch

[Dieselpwrdredneck]

How often should the AC clutch get engaged? Is it supposed to come on with your defroster? Can you tell a big difference in the truck at an idele when it kicks on? i can here my truck bog down quit a bit when the clutch engages. Is this normal?

Thanks
Neal

 

[MUDWHISTLE]

It will cycley anywhere from ever 30 secoonds to 2-3 minutes depending on how hot it is and how much air flow you are running across the evaporator. Yes they come on when the defroster is on I have heard that it helps produce a dryer air to keep from fogging the windows up. I would not think that it would bg down very far as the computer should keep the engine at its set idle speed. Mine is not really noticable when it cycles on and off. maybe your compressore is dragging. How does the a/c work?

 

[Dieselpwrdredneck]

AC works great, the engine recovers when it bogs down, it just bogs down when it first comes on

Neal

 

[94f450sd]

completely normal.the compressor cycles every few minutes with theheater/defroster on just to keep theoil flowing through it to keep it from seizing up in the winter.the drop in idle when it kicks on is normal also as it takes a good bit of power to get it spinning.

 

[MUDWHISTLE]

I think it robs 10 to 15 horsepower to run an a/c compressor in really hot conditions when the pressures are up at higher levels.

 

[BJS]

There is a chart that will tell you at a fixed rpm the expected cycle times for the a/c on a ford based on the FFO (Fixed flow oriface) design of our a/c systems. However at idle the compressor should run pretty much nonstop if it is cycling at idle rapidly then you more than likely are tripping the low presure switch on the suction side of the compressor so it's kicking off and as the pressure re equalizes it's kicking back on.

Your truck should not bog down at all when the compressor kicks on because there is plenty of excess power at idle on these engines. If it is noticeable then you might have a compressor that is getting ready to sieze Having messed with enough a/c systems I can say that I can turn the compressor by hand and have a pretty good idea of if the compressor is in good shape or if it's getting worn.

The compressor kicking on with defrost is normal. It's a design that uses the ability of the a/c system to remove moisture from the air to accellerate the evaporation of the condensation on your winshield. Hot dry air will evaporate moisture more rapidly than hot moist air. If it's hot you can defrost the winshield using cold air it will just take a bit longer which is nice to keep from flipping the heat on in the middle of the summer if you happen to fog up the windows.