General QuestionsGeneral questions related to 1999-2007 Super Duty trucks. If it doesn't fit the other categories, post it here. Gas engine discussion that pertains to all models is allowed. Specific gas engine questions should use the Gas Engines forum.
2000 f-350 , a/c clutch has quit cycling, everyhting is right , what makes the clutch cycle on these trucks? i know on the semis like i work on there is usuallya thermostat but i cant seem to locate oneon my truck. any help will be greately appreciated
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2000 F-350 4x4 6spd CC Lariat service truck
2002 F-550 4x4 6spd CC Lariat service truck
2004 F-550 2x4 auto CC Lariat service truck
2008 F-550 4x4 auto CC KR service truck
The clutch cycling switch is on the accumulator. It opens at about 25 psi and resets at about 45 psi. If you are wanting it to cycle while idling on a hot day, good luck. You can set the AC on MAX, fan speed on low, rev the engine to about 1500 RPM and make it cycle.
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2000 F250 Lariat CC SB 4x4 PSD Auto
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2000 F-350 4x4 6spd CC Lariat service truck
2002 F-550 4x4 6spd CC Lariat service truck
2004 F-550 2x4 auto CC Lariat service truck
2008 F-550 4x4 auto CC KR service truck
Generally speaking,the clutch should stay engaged on a hot day @ idle if all is working fine.When you increase rpm's the head pressure increases and therefore the high pressure switch dis-engages the clutch to lower head pressure.
If you have one that is cycling on/off quickly....most likely it is low on freon.
Generally speaking,the clutch should stay engaged on a hot day @ idle if all is working fine.When you increase rpm's the head pressure increases and therefore the high pressure switch dis-engages the clutch to lower head pressure.
The low pressure switch is what makes the clutch cycle. The HP switch is a safety feature. On a healthy system, increasing the engine RPM will lower the high side pressure.
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2000 F250 Lariat CC SB 4x4 PSD Auto
the air gap may be too large. Try what I did, remove the bolt on the front of the clutch and remove. There is a washer/spacer where the clutch inserts into the compressor. Remove the spacer and reinstall the clutch. My works just fine. Or you could just replace your clutch. See if that works.
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Early 99 F250 Crew Cab. South Texas Outfitters grill guard and bumper. Rhino linered bed covered by a SnugTop Snuglid. Homemade Tymar. Rockford/Fosgate speakers. Nitrogen filled tires and a quiet torque converter. 98 gal bed mounted aux tank. PIAA pencil beam lights Otherwise quite stock.
Quote:
Originally Posted by OCOMOF05 Generally speaking,the clutch should stay engaged on a hot day @ idle if all is working fine.When you increase rpm's the head pressure increases and therefore the high pressure switch dis-engages the clutch to lower head pressure.
The low pressure switch is what makes the clutch cycle. The HP switch is a safety feature. On a healthy system, increasing the engine RPM will lower the high side pressure.
When you increase engine rpm your increasing compressor output. Therefore RAISING head pressure and LOWERING suction pressure. Ambient temp is directly related to your pressures. If its hot out low/hi pressures are going to be higher. IF its cool out, pressures are going to lower. Your low side pressure reading is also directly related to evap temp. so if your pressure drop enough your evap will freeze up. That is why they put a low side pressure switch so your a/c cycles.
Therefore if its not all that hot out and your running your fan speed on low, theres not alot of air crossing the evap, so the pressure get to low, so the switch stops the compressor to keep the low side in proper pressure.
When you increase engine rpm your increasing compressor output. Therefore RAISING head pressure and LOWERING suction pressure. Ambient temp is directly related to your pressures. If its hot out low/hi pressures are going to be higher. IF its cool out, pressures are going to lower. Your low side pressure reading is also directly related to evap temp. so if your pressure drop enough your evap will freeze up. That is why they put a low side pressure switch so your a/c cycles.
Therefore if its not all that hot out and your running your fan speed on low, theres not alot of air crossing the evap, so the pressure get to low, so the switch stops the compressor to keep the low side in proper pressure.
You understand part of it correctly but you need to read parts of your book again.
Increasing the RPM increases compressor and cooling fan speed. This causes the both the evaporator pressure and the condenser temp to decrease.
I also prefer to say pressure is related to the ambient temp instead of saying ambient temp is related to your pressure. Perhaps you meant to say discharge air temp is directly related to evap pressure.
The rest of the stuff you got correct.
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2000 F250 Lariat CC SB 4x4 PSD Auto
the air gap may be too large. Try what I did, remove the bolt on the front of the clutch and remove. There is a washer/spacer where the clutch inserts into the compressor. Remove the spacer and reinstall the clutch. My works just fine. Or you could just replace your clutch. See if that works.
I believe the OP asked his question because his compressor was running continuously.
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2000 F250 Lariat CC SB 4x4 PSD Auto
The low pressure switch is what makes the clutch cycle. The HP switch is a safety feature. On a healthy system, increasing the engine RPM will lower the high side pressure.
Quote:
Originally Posted by 444-4D
You understand part of it correctly but you need to read parts of your book again.
Increasing the RPM increases compressor and cooling fan speed. This causes the both the evaporator pressure and the condenser temp to decrease.
I also prefer to say pressure is related to the ambient temp instead of saying ambient temp is related to your pressure. Perhaps you meant to say discharge air temp is directly related to evap pressure.
The rest of the stuff you got correct.
maybe if your overcharged and not getting air flow over the condensor, but not with a system that is working properly. Iam not trying to argue or be an ass, but that doesnt make sense. Thats like saying when you raise rpm the water pump flows less coolant. Being in south fla, I have worked on quit a bit of a/c's and have never seen or herd of that.
maybe if your overcharged and not getting air flow over the condensor, but not with a system that is working properly. Iam not trying to argue or be an ass, but that doesnt make sense. Thats like saying when you raise rpm the water pump flows less coolant. Being in south fla, I have worked on quit a bit of a/c's and have never seen or herd of that.
Hopefully you don't think these statements make sense.
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2000 F250 Lariat CC SB 4x4 PSD Auto
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