Air Conditioning
FTE Chapter Leader
Joined: Jan 2005
Posts: 13,127
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From: Henderson, NV
IIRC last year some guys talking about an addative that made the AC perform better. Was going to do it to mine, but never got around to that or installing the bypass valve. I think @Sous and @SkySkiJason were both in on the conversation since I recall it coinciding with discussion about one of the NGA G2Gs.
The performance enhancer is called cool shot ultra made by errcom. It works pretty well, I used it on my truck before I replace the entire AC system and it definitely helped some. As mentioned before the aftermarket blower motors do not push nearly as much air as the motorcraft units, I found that out the hard way.
On edit: x3 on the bypass valve, a 3/4 PEX ball valve fits perfectly in the line going to the heater core. Simple , cheap quick fix and it works.
On edit: x3 on the bypass valve, a 3/4 PEX ball valve fits perfectly in the line going to the heater core. Simple , cheap quick fix and it works.
https://www.ford-trucks.com/forums/1...r-testing.html
Banned
Joined: Dec 2018
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Normally when the low side gets to about 25 psi, the compressor cycles off. This is to prevent freeze up of the evaporator, cycle off the compressor at very high rpms and shut it off if there is low charge.
If you have to downshift going up a hill or have low gearing and high rpms on the freeway it can cause your compressor to constantly cycle.
I replaced the low switch with one that I can adjust with the adjustment screw to lower it down to say 19 psi. The OEM 25 psi is about 29 degreesF at the evap core when it cycles off. So your air coming out will be at best 38 degrees with low humidity. Im in PHX so humidity is LOW, I can get down to about 20 theoretical degrees at the evap at about 19 psi. The truck does not normally run that low however unless high rpms or low blower. My air is real cold about 32 when cruising. It does nothing for idle.
If you have to downshift going up a hill or have low gearing and high rpms on the freeway it can cause your compressor to constantly cycle.
I replaced the low switch with one that I can adjust with the adjustment screw to lower it down to say 19 psi. The OEM 25 psi is about 29 degreesF at the evap core when it cycles off. So your air coming out will be at best 38 degrees with low humidity. Im in PHX so humidity is LOW, I can get down to about 20 theoretical degrees at the evap at about 19 psi. The truck does not normally run that low however unless high rpms or low blower. My air is real cold about 32 when cruising. It does nothing for idle.
Do you know by chance what the high side pressure switch is looking for? On mine the pressure relief valve has purged twice while parked making a mess before I could shut it off. From what I have read that valve is not supposed to vent until 480 psi high side, and I have watched mine creep all the way up to 450 last week playing around with the gauges and it held. Does this sound like a possibly faulty high side switch? ForScan PID for that switch is "ACP" and it shows "Open" (Okay) whether the system is on or off, so I can not see if it is responding and working like I can with the low side switch.
Hotshot
Joined: Dec 2012
Posts: 11,278
Likes: 1,658
From: Las Cruces New Mexico
Great info. Is there a link to more info about this adjustable switch?
Do you know by chance what the high side pressure switch is looking for? On mine the pressure relief valve has purged twice while parked making a mess before I could shut it off. From what I have read that valve is not supposed to vent until 480 psi high side, and I have watched mine creep all the way up to 450 last week playing around with the gauges and it held. Does this sound like a possibly faulty high side switch? ForScan PID for that switch is "ACP" and it shows "Open" (Okay) whether the system is on or off, so I can not see if it is responding and working like I can with the low side switch.
Do you know by chance what the high side pressure switch is looking for? On mine the pressure relief valve has purged twice while parked making a mess before I could shut it off. From what I have read that valve is not supposed to vent until 480 psi high side, and I have watched mine creep all the way up to 450 last week playing around with the gauges and it held. Does this sound like a possibly faulty high side switch? ForScan PID for that switch is "ACP" and it shows "Open" (Okay) whether the system is on or off, so I can not see if it is responding and working like I can with the low side switch.
Granted your AC system isn't contaminated/blockage there's a high chance you fan Clutch isn't working, just fixed this the other day in my work truck..
Here's what I posted on the other thread.
"Just my luck, my work truck started doing the same thing this past week, put it off for the entire week as I noticed it only happened when I was idling and increasing the rpm's to 2k took care of that blow off/ safety valve. So just recharged it and strated to diagnose the problem today.
Since my AC system was all replaced 5+ years ago, so I doubt it was blockage in the system, and evacuating and removing the Orifice tube confirmed that the system is still spotless.
Gauges were reading very high at idle in the shop with ambient temp in the high 70's, threw some water in the condenser and readings immediately went to the upper 30's on the low side in the 190'ish in pressure.
The fan was spinning "fine" but noticed that I couldn't feel air being sucked in, thought it was weird, since you can usually feel air being sucked in thru the condenser. So long story short the fan clutch was capoot. When I removed the fan clutch the temp coil was covered in oily dirty, and when spinning it by hand it felt like a "good" clutch, but the faster I tried to spin it the looser it got. So a new fan clutch from the local parts store and AC is up and running 100%.
So check the fan clutch just to make sure it's actually working right, ad make sure all the fins on the condenser, trans cooler, IC, and radiator are clean of debris"
Banned
Joined: Dec 2018
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Granted your AC system isn't contaminated/blockage there's a high chance you fan Clutch isn't working, just fixed this the other day in my work truck..
Here's what I posted on the other thread.
"Just my luck, my work truck started doing the same thing this past week, put it off for the entire week as I noticed it only happened when I was idling and increasing the rpm's to 2k took care of that blow off/ safety valve. So just recharged it and strated to diagnose the problem today.
Since my AC system was all replaced 5+ years ago, so I doubt it was blockage in the system, and evacuating and removing the Orifice tube confirmed that the system is still spotless.
Gauges were reading very high at idle in the shop with ambient temp in the high 70's, threw some water in the condenser and readings immediately went to the upper 30's on the low side in the 190'ish in pressure.
The fan was spinning "fine" but noticed that I couldn't feel air being sucked in, thought it was weird, since you can usually feel air being sucked in thru the condenser. So long story short the fan clutch was capoot. When I removed the fan clutch the temp coil was covered in oily dirty, and when spinning it by hand it felt like a "good" clutch, but the faster I tried to spin it the looser it got. So a new fan clutch from the local parts store and AC is up and running 100%.
So check the fan clutch just to make sure it's actually working right, ad make sure all the fins on the condenser, trans cooler, IC, and radiator are clean of debris"
Here's what I posted on the other thread.
"Just my luck, my work truck started doing the same thing this past week, put it off for the entire week as I noticed it only happened when I was idling and increasing the rpm's to 2k took care of that blow off/ safety valve. So just recharged it and strated to diagnose the problem today.
Since my AC system was all replaced 5+ years ago, so I doubt it was blockage in the system, and evacuating and removing the Orifice tube confirmed that the system is still spotless.
Gauges were reading very high at idle in the shop with ambient temp in the high 70's, threw some water in the condenser and readings immediately went to the upper 30's on the low side in the 190'ish in pressure.
The fan was spinning "fine" but noticed that I couldn't feel air being sucked in, thought it was weird, since you can usually feel air being sucked in thru the condenser. So long story short the fan clutch was capoot. When I removed the fan clutch the temp coil was covered in oily dirty, and when spinning it by hand it felt like a "good" clutch, but the faster I tried to spin it the looser it got. So a new fan clutch from the local parts store and AC is up and running 100%.
So check the fan clutch just to make sure it's actually working right, ad make sure all the fins on the condenser, trans cooler, IC, and radiator are clean of debris"
Fleet Owner
Joined: Jun 2004
Posts: 25,090
Likes: 1,112
From: Rio Rico, AZ.
If you have doubts about the high pressure switch, just get a new one plus a plug repair kit and replace it. I'm on my third one now and the second plug repair kit. There's a check valve underneath it that will hold the AC charge when you remove the high pressure switch. It seems to be a common failure point.
Cargo Master
Joined: Sep 2015
Posts: 2,860
Likes: 365
Just a heads up if you decide to replace the high pressure switch with a motorcraft you will most likely have to get a new pigtail for it as they changed designs on the plug. Aftermarket still seems to have the same plug. This is what my local motorcraft dealer told me so I had them pull the part and sure enough the plug is not the same on the newer high pressure switches
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1st Gear
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For a beefier blast of cool air, you could also inspect your AC hoses for damage and ensure there aren't any leaks. Sometimes, the refrigerant tubes could also be blocked or compressed which affecting airflow. Furthermore, your air filter might need to be replaced if it's clogged up with grime or dust. Still, I'm not an expert here, so it's better to reach out to a hamilton air conditioner repair service.
Last edited by skipandtry; Sep 1, 2023 at 08:58 AM.
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