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What would cause my a/c to work for a few minutes and then stop blowing cool air? Any help is appreciated. Btw it's a 99 Ford F350.
 

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What would cause my a/c to work for a few minutes and then stop blowing cool air? Any help is appreciated. Btw it's a 99 Ford F350.
if its sitting still i would say the fan isnt moving air over the condenser, if its driving you could have a restriction (stopped up orifice tube or expansion valve) for a start. check to see if the high side pressure is building too high... = +300psi
 

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quite a fiew things but usually its a phenomenon called cold coil where freon is too low and will cause the evaporator to freeze verry quickly and will cause compresser to shut off due to to low of low side pressure . throw some gauges on it
 

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Thanks guys. Maybe the freon is low? It blows cold for 3 or 4 minutes and then gets hot. I figured if the freon was low I wouldn't get any cold air? No a/c when its 80 out sucks!
 

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I had the same problem and so did a buddy of mine. He has a 2000 and I have a 2001. The clutch on the AC compressor has to be shimmed. Mine was at like 40 thousandths and it was supposed to be at like 10 thousandths. When truck is accelerating, it was fine, but stop and idle or drive slowly and it would not blow cold. I'm telling you this is probably it. I checked everything else under the sun. Hope this helps Trace.......Lucas
 

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I had the same problem and so did a buddy of mine. He has a 2000 and I have a 2001. The clutch on the AC compressor has to be shimmed. Mine was at like 40 thousandths and it was supposed to be at like 10 thousandths. When truck is accelerating, it was fine, but stop and idle or drive slowly and it would not blow cold. I'm telling you this is probably it. I checked everything else under the sun. Hope this helps Trace.......Lucas
Did you shim it yourself? Is there much involved with this? It acts like you described! Thanks! :)
 

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I didn't shim it myself, but I'm sure it isn't that difficult. It's right on front of the AC compressor.
 

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I didn't shim it myself, but I'm sure it isn't that difficult. It's right on front of the AC compressor.
X2, I see this fairly often at the dealership. Once the clutch warms up, the feild can't pull the disc tight to the pulley anymore if the gap is worn too big. The clutch disc is held on the front by one 8mm head bolt. Just remove the bolt and the disc slides right off. There is a small washer under the disc to set the clutch gap, and you'll either need to find a thinner one(a clutch disc shim kit is available) or remove it all together depending on wear on the disc. Shoot for as tight a gap as possible without the disc dragging on the pulley(.010"-.015") and you should be good to go.
 

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I am gonna say with that old of a model leaking o-rings and low charge. Replace o-rings, accumulator, orfice, evacuate for at least 20 min and recharge with 2 ibs of refrigerant. low side pressure should be 30-40 psi and 180-240 high side at 1500 rpms.
 

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X2, I see this fairly often at the dealership. Once the clutch warms up, the feild can't pull the disc tight to the pulley anymore if the gap is worn too big. The clutch disc is held on the front by one 8mm head bolt. Just remove the bolt and the disc slides right off. There is a small washer under the disc to set the clutch gap, and you'll either need to find a thinner one(a clutch disc shim kit is available) or remove it all together depending on wear on the disc. Shoot for as tight a gap as possible without the disc dragging on the pulley(.010"-.015") and you should be good to go.
That has to be it. I'll do it tonight and let you know. Thanks :)
 

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FWIW, I have seen a few cars and trucks in this model year range have a bad low pressure switch also. If the charge is good and the clutch gap is within spec.try jumping the pressure switch connectors if the clutch stops cycling after the vehicle has warmed up.
 

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I've heard that putting a valve (either electronic or ball valve) in the heater-core feed line helps a ton with the A/C's capability. Have any of you guys tried that?
 

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I've heard that putting a valve (either electronic or ball valve) in the heater-core feed line helps a ton with the A/C's capability. Have any of you guys tried that?
That would help lower the temp in the heater box, but shouldn't be necessary as long as the blend door is sealing properly.
 

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Discussion Starter #15
Air, hell we shut the heat off a week ago, make up your mind! Sheeeeeeze


Hey Trace
Hi Scott! If I didn't have to talk on the phone all the damn time I'd just leave the windows down. :p
 

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I had the same problem and so did a buddy of mine. He has a 2000 and I have a 2001. The clutch on the AC compressor has to be shimmed. Mine was at like 40 thousandths and it was supposed to be at like 10 thousandths. When truck is accelerating, it was fine, but stop and idle or drive slowly and it would not blow cold. I'm telling you this is probably it. I checked everything else under the sun. Hope this helps Trace.......Lucas
Had this same problem on my Explorer, real easy to do especially if the compressor is on top, dont even have to remove the belt. Air gap should be between .014 and .030.
 
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