E99 a/c questions
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Lead Driver
Joined: Oct 2005
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From: Ponca City, OK
E99 a/c questions
I don't think my a/c is working as good as it should. So far I've checked the refrigerant, cleaned the condenser, and removed the washers on clutch. My question is, is the compressor supposed to cycle while on max a/c? If so how often? When I run the a/c it's always on max w/ high fan. The air cycles between cold and just cool. Mostly just cool. Usually seems to run cooler at ilde than running down the highway at 55-65. I'm hoping y'all can help me figure out what if anything could be wrong. My opinion, running down the highway for an hour w/ everything on max I should be freezing, instead I'm barely comfortable. I'm considering replacing the clutch assembly, I also saw a video on swapping in a smaller orifice, but I hate blindly throwing parts at it. Especially if there's something cheap/ simple I could do to fix it. Thanks for any help I can get.
FTE Chapter Leader
Joined: Jan 2005
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From: Henderson, NV
Nope, the compressor clutch is not supposed to cycle. There are 3 possibilities:
1. Too little refrigerant. Low pressure switch is activating.
2. Too much refrigerant. High pressure switch is activating.
3. Compressor clutch solenoid is failing or clutch is so worn that removing shims is still not enough to fix it.
Check to see that your vacuum lines are in good shape. Your blend door may be redirecting air through your heater core if you have a vacuum leak. You can also do the heater cutoff valve mod so no hot coolant runs through the heater core when in Max AC mode.
1. Too little refrigerant. Low pressure switch is activating.
2. Too much refrigerant. High pressure switch is activating.
3. Compressor clutch solenoid is failing or clutch is so worn that removing shims is still not enough to fix it.
Check to see that your vacuum lines are in good shape. Your blend door may be redirecting air through your heater core if you have a vacuum leak. You can also do the heater cutoff valve mod so no hot coolant runs through the heater core when in Max AC mode.
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Lead Driver
Joined: Oct 2005
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From: Ponca City, OK
Is there a way to check the high and low pressure switch to rule that out? I've checked the refrigerant, w/ one of those bs gauges that come w/ the can but still always shows on the high side of safe range.
FTE Chapter Leader
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From: Henderson, NV
Not without a proper gauge set unfortunately. The gauge that comes with a can is woefully inadequate. With the engine at idle, your lo-side should read around 40psi and your high side should read no more than 350psi.
FTE Chapter Leader
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From: Henderson, NV
Originally Posted by udsuth78
Any other things to check for
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Fleet Mechanic
Joined: Jul 2003
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From: Springfield, PA
Just confirming, when on max a/c the compressor runs all the time? I always thought the difference between max and regular a/c was recirculating air (max) or drawing in outside air (regular).
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FTE Chapter Leader
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From: Henderson, NV
Originally Posted by SaintITC
Just confirming, when on max a/c the compressor runs all the time? I always thought the difference between max and regular a/c was recirculating air (max) or drawing in outside air (regular).
Cargo Master
Joined: Aug 2003
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From: Eastern Washington
The compressor cycles in normal operation. As mentioned, MAX has nothing to do with the compressor. AC is either on or off, the pressure switches decide when it cycles on and off.
Looking at pressures won't tell you if your refrigerant is properly charged. You need to evacuate it and weigh it to see whats in there. If you haven't added any I'm sure it's low.
Evacuate it, vacuum the system for 15-30 minutes, confirm it holds vacuum and put the correct amount in. 2.5# if I recall correctly, unless it's an Ex w/ rear air.
Looking at pressures won't tell you if your refrigerant is properly charged. You need to evacuate it and weigh it to see whats in there. If you haven't added any I'm sure it's low.
Evacuate it, vacuum the system for 15-30 minutes, confirm it holds vacuum and put the correct amount in. 2.5# if I recall correctly, unless it's an Ex w/ rear air.
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Lead Driver
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From: Ponca City, OK
Alright got the gauges and a temp probe. The high side was 200-205 and the low side was 30-32. Temp at vent was 70 while running down the road and 60 at idle. Something is definitely not right. Never did see the compressor kick out either. For those interested gauges were $47.80 w/ coupon. Score.
Cargo Master
Joined: Aug 2003
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From: Eastern Washington
Whats ambient temp?
70/60 is terrible, but 200/30 is pretty good. 250/30 would be better, but thats ambient temp dependant also.
Is the drier nice and cold?
I'd check the blend door operation and make sure it's not mixing warm air as Noob mentioned earlier.
70/60 is terrible, but 200/30 is pretty good. 250/30 would be better, but thats ambient temp dependant also.
Is the drier nice and cold?
I'd check the blend door operation and make sure it's not mixing warm air as Noob mentioned earlier.
Tuned
Joined: Oct 2006
Posts: 286
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From: Northern Virginia
Could be a blend door issue as well, but with both the high and low sides reading low I would try charging it first. I would imagine going down the highway your pressures would be even lower (more air across the condenser and more RPM) and the low pressure switch is cycling the compressor off.