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Compressor cycling too much?

jed1154 on Sun January 13, 2008 3:27 PM User is offline

Year: 2005
Make: Ford
Model: F-250
Engine Size: 6.0
Refrigerant Type: 134

I have noticed that my AC seems to cool OK, but the comprssor seems to cycle a lot. In 60 degree weather, it from the time the compressor clicks OFF to the time it clicks ON is about 10 seconds, sometimes its 12 or so. The compressor usually stays on for about 7 seconds or so i THINK.

Is this too much? Too little? My other vehicles under similar conditions seem to leave teh compresso ON for much longer, resulting in fewer cycles.

Can this be any indication at all of low charge?

Chick on Sun January 13, 2008 4:05 PM User is offlineView users profile

At 60 degrees it will cycle more frequently, but it sounds more to me like a low charge, the way you describe it anyway...Maybe getting the pressures will tell us more. High side should reach around 145psi before it cycles off....if it doesn't, I'd evac and recharge the system amount back in..I really don't like topping off a system with ambients under 70 to 75 degrees.. Feel the suction line, it should be very cold right back to the compressor.. If not, low charge is suspect..Working at 60 degrees on an AC system, I would always evacuate the system and recharge.. Just to cold to get proper pressures.. Hope this helps...

PS: look for signs of a leak, around all fittings, condenser, etc...

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

jed1154 on Sun January 13, 2008 7:04 PM User is offline

Im not comfortable putting the gauges on it. Its under warranty, but that sort of sucks even more because the dealers dont always do it the right way. Unfortunately, all i can do is see how long it cycles and try to determine if its worth taking in or not. There is a bulletin on the AC system on this model of trucks for "rapid compressor cycling", but i have no idea what 'rapid' means and it is three months short of the date my truck was built (so it doesnt apply). There are no leaks in the system, its always been like this since i bought it, i was just wondering if it was possibly undercharged from the factory. Any idea what 'rapid' means?

Edited: Sun January 13, 2008 at 7:18 PM by jed1154

Chick on Sun January 13, 2008 7:13 PM User is offlineView users profile

I understand, but you do risk the compressor going out due to "lack of lubrication" on low charge..Something to think about..

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

jed1154 on Sun January 13, 2008 8:26 PM User is offline

Then it may be worth checking out.

You think 10 seconds between off and on cycles is too much?

Chick on Sun January 13, 2008 9:33 PM User is offlineView users profile

Once the engine is at operating temps, should stay on longer than ten seconds while idling even in 60 degree weather..(moving it will cycle more due to cold air flow over the condenser) You can put a piece of cardboard over the condenser to raise the pressures long enough to take pressures and feel the suction line...Has to be cold back to the compressor, not just cool at that temp..Watch the temperature gauge when doing that though...Short answer, yes it should be looked into or you due risk compressor damage and a much costlier repair..Hope this helps..

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

jed1154 on Mon January 14, 2008 10:15 AM User is offline

Ill check again. I misunderstood your post. I will see how long the compressor stays ON. I meant from the time it cycles OFF to the time it clicks back on was about 10-12 seconds depending on temp.

Thanks for the info.

Chick on Mon January 14, 2008 10:25 AM User is offlineView users profile

That could well be normal, I misunderstood it to be cycling off every 10-12 seconds...

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

jed1154 on Mon January 14, 2008 10:38 AM User is offline

So when they say it should cycle in cold weather, does that mean the compressor should come ON and stay on?

NickD on Mon January 14, 2008 10:52 AM User is offline

Fords seem to be terrible in this respect and extremely difficult to find a position on your mode switch that actually turns the compressor off. In 40*F weather, seen these thing pop on the compressor for two seconds, rest for about 15 seconds and come back on again.

One solution is to pull the compressor coil plug and tie if off, remembering to put it back on for warranty work, ha, the way they are making cars today, you will need to.

Not sure what the thinking is on running the compressor if thinking is even the correct word. It's not doing a darn bit of good, doesn't say on long enough to even begin to pull out moisture. One thought is to wear it out after warranty if it last that long, but check your warranty, most AC's are only covered for the first year, so after seeing the repair bill from your dealer, you are tempted to buy a new car.

Chick on Mon January 14, 2008 10:53 AM User is offlineView users profile

The hotter it is, the "less" it will cycle, the colder it is, the "more" it will cycle.. On a 90 degree day with high humidity, some won't ever cycle.. Pressures are also temperture related..and the amount of heat being removed fits into the mix to..

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

jed1154 on Wed January 16, 2008 10:25 AM User is offline

OK, i checked it again. The compressor stays ON for about 10-11 seconds, and OFF for about the same. This is with 50 degrees ambient temps. Guess its just the way the system is. I know it takes about 45oz of refrigerant according to ford. Its seems to cool off well, even when its 110 outside, so i guess no worries. I think my wifes stays on for 15 seconds and off for 15 seconds at teh same temp, but its a F-150 and smaller system.

NickD on Wed January 16, 2008 12:11 PM User is offline

Our 98 ZX2 is that way, do not feel it's a good idea, that's 3 cycles per minute and on a ten hour drive, the compressor is expected to accelerate from zero to 2,700 RPM in a fraction of a second, that's 1,800 rapid starts! Wears the thing down to nothing. My DeVille is like that in Auto mode, but switches off the compressor in Econ mode, and that is where that switch stays on trips on cool days. It switches on in Defrost mode, but I only leave it there for a couple of minutes until the fog disappears and as the car heats up, the fog stays away.

On the ZX2, the only modes that leaves the compressor off are Heat, and off, stupid thing even runs in the Vent mode, so what why in the hell do they have an AC mode?

My 04 Cavalier has a compressor switch that is worthless in either the Defrost or Recir modes, dump compressor comes on anyway, unless the temperature is at absolute zero. Only cars that made sense are the Japanese cars, gosh I miss that continuously variable recir lever and a compressor switch that when off, it stays off.

If you think it's bad at 50*F, try 40*F, more like 6-8 cycles per minute, really wearing the damned thing out and next to worthless. Not only the compressor, but it's clutch and the entire drive belt chain with every bearing in it.

jed1154 on Wed January 16, 2008 12:19 PM User is offline

If i dont put it on AUTO, i can keep the compressor off. You think thats a good idea, until the AC is actually needed? I think it is.

This system is very automatic, it has an automatic valve to close off coolant to the heater core when in AC mode. They just make the compressor run so it stays lubed i guess.

I think ill hang out a while and recheck the system in the summertime. I dont know why the wife's runs for 5 seconds longer at the same temp except for it being a different sized system?

NickD on Wed January 16, 2008 1:40 PM User is offline

Quote
They just make the compressor run so it stays lubed i guess.

Compressor is already lubed, in an airtight moisture free system with positive pressure, so do not feel that is the reason. Another item is the compressor seal, gets quite a jerk when the compressor is kicked on and when cold that seal is as stiff as a board, doesn't respond as quick and refrigerant is lost.

I can't think of a good reason why they permit compressor operation at cold temperatures, on long trips on cold days, can't be moisture removal, the air in the vehicle is already way too dry, feel it in the throat. Simple explanation, as air cools, it's ability to hold moisture is drastically reduced, when heated by the heater core, the RH drops to nothing, if anything, moisture should be added to the interior.

Only thing it does is wears out the compressor, belt drive train, and loses refrigerant, okay for the repair business.

jed1154 on Wed January 16, 2008 4:22 PM User is offline

Well, i know on mine, the AUTO setting mixes outside air. Why, i don't know. It only starts off with recirc if its really hot. So, maybe its just to dry that air. I tried turning the compressor off today, and the air is noticably stickier. As it recirculated thouhg, it would probably dry as you said.

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