Only blows cold when driving

[BlacksonAudio]

I’m sure it’s posted in here somewhere... so while driving AC will freeze your balls off. But at idle cool to lukewarm. Day or night. No codes from DATC and I replaced the DCCv (Motorcraft) earlier this year. I’m thinking radiator or intercooler. V8 3.9 2002.

 

[BlacksonAudio]

Also who has experience with p0442 code? I’ve changed the gas cap. Code comes and goes.

 

[joegr]

I’m sure it’s posted in here somewhere... so while driving AC will freeze your balls off. But at idle cool to lukewarm. Day or night. No codes from DATC and I replaced the DCCv (Motorcraft) earlier this year. I’m thinking radiator or intercooler. V8 3.9 2002.

The most likely cause is that your engine cooling fan is not operating or not operating correctly.
A much less likely cause (but it has happened) is a bad scroll control valve in the AC compressor.
You have the hydraulic fan, odds are by far that it is the fan.

 

[BlacksonAudio]

The most likely cause is that your engine cooling fan is not operating or not operating correctly.
A much less likely cause (but it has happened) is a bad scroll control valve in the AC compressor.
You have the hydraulic fan, odds are by far that it is the fan.

 

[BlacksonAudio]

The most likely cause is that your engine cooling fan is not operating or not operating correctly.
A much less likely cause (but it has happened) is a bad scroll control valve in the AC compressor.
You have the hydraulic fan, odds are by far that it is the fan.

I have another Hydraulic fan pump with actuator. I’ll replace that my next day off. Maybe it’s the pump that’s going.

 

[Caleb]

I’m sure it’s posted in here somewhere... so while driving AC will freeze your balls off. But at idle cool to lukewarm. Day or night. No codes from DATC and I replaced the DCCv (Motorcraft) earlier this year. I’m thinking radiator or intercooler. V8 3.9 2002.

I’m having same issue. Also, while idling, I can rev up to 1500-2000 RPM and notice it gets cold also. Is yours the same?

 

[Vee8Guy]

I have another Hydraulic fan pump with actuator. I’ll replace that my next day off. Maybe it’s the pump that’s going.

If your car isn't overheating when sitting still it probably isn't your fan pump. I agree that the fan probably isn't being triggered to turn on when the AC is on. Yours is the classic symptom of the fan not turning on. On older cars there was a switch in the instrument panel that sensed to position of the AC lever. Since this car is "digital" I'm sure there's some other method.

 

[joegr]

If your car isn't overheating when sitting still it probably isn't your fan pump. I agree that the fan probably isn't being triggered to turn on when the AC is on. Yours is the classic symptom of the fan not turning on. On older cars there was a switch in the instrument panel that sensed to position of the AC lever. Since this car is "digital" I'm sure there's some other method.

Even on older cars, it rarely (if ever) worked that way. On the LS, like most, there is a pressure transducer on the high side AC line. As the pressure there gets higher, the fan gets faster (it is not an on or off thing, it is variable speed control). The fan won't speed up if the pressure does not go up, and it wouldn't change anything if it did if the pressure isn't there. Pressure could be too low due to low refrigerant (leak), a bad expansion valve, or a bad scroll control valve in the compressor. You have to put low and high side gauges on to tell, if you understand the readings that you get.

 

[joegr]

I’m having same issue. Also, while idling, I can rev up to 1500-2000 RPM and notice it gets cold also. Is yours the same?

This symptom suggests a bad scroll control valve, but it could be a few other things. The high and low side pressures at idle and at 2K RPM would confirm or rule that out.

 

[Caleb]

This symptom suggests a bad scroll control valve, but it could be a few other things. The high and low side pressures at idle and at 2K RPM would confirm or rule that out.

great to hear. help me clarify, when checking pressure, does it make a difference if recirculate, Auto, etc are on? I had pressure checked, and low side was significantly high (around 70-75 if I remember correctly). But, noticed the Auto Climate was on. Seems to be cooler when setting manual, no auto.

 

[joegr]

great to hear. help me clarify, when checking pressure, does it make a difference if recirculate, Auto, etc are on? I had pressure checked, and low side was significantly high (around 70-75 if I remember correctly). But, noticed the Auto Climate was on. Seems to be cooler when setting manual, no auto.

Correct settings are: Set to min temperature, set to max fan speed, set to fresh (not recirculate), and open all the windows. It also helps to know the exterior temperature. Really need to know the high side pressure at the same time. Just having the low side pressure only tells a part of the story. It is not enough.

 

[Caleb]

Correct settings are: Set to min temperature, set to max fan speed, set to fresh (not recirculate), and open all the windows. It also helps to know the exterior temperature. Really need to know the high side pressure at the same time. Just having the low side pressure only tells a part of the story. It is not enough.

Got it! Perfect.
I do not remember readings on high side, he just said it was within range. However, now I can see settings were incorrect, I will perform new reading and update after.

 

[Caleb]

Correct settings are: Set to min temperature, set to max fan speed, set to fresh (not recirculate), and open all the windows. It also helps to know the exterior temperature. Really need to know the high side pressure at the same time. Just having the low side pressure only tells a part of the story. It is not enough.

test ran with suggested method. got 2 readings. 1 with engine off, 1 with engine on.

Off - Ambient Temp around 90 Degrees - Low 105PSI High 125PSI
On, recirculate off, 60 degree temp, full blast, 2kRPM - Low 55PSI High - 195

what say ye?

 

[clubairth]

Looks like it's a bit low on Freon to me. Too high a pressure on the low side. So little or no cooling with 55 psi on the low side.
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[Caleb]

Looks like it's a bit low on Freon to me. Too high a pressure on the low side. So little or no cooling with 55 psi on the low side.
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AC will freeze you while car is driving, or holding 2kRPM. while sitting at idle, not very cold at all. you still agree low freon?

 

[clubairth]

Maybe it's an airflow problem instead?
How is the fan running? Comes on with the AC?
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[Caleb]

Maybe it's an airflow problem instead?
How is the fan running? Comes on with the AC?
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fan running fine. condenser and radiator clean.

 

[joegr]

test ran with suggested method. got 2 readings. 1 with engine off, 1 with engine on.

Off - Ambient Temp around 90 Degrees - Low 105PSI High 125PSI
On, recirculate off, 60 degree temp, full blast, 2kRPM - Low 55PSI High - 195

what say ye?

I'm sorry that I wasn't clear enough. I need

1. Low side and high side recirulate off, 60 degree setting, full blast, engine on but at idle (about 750 RPM)
2. Low side and high side recirulate off, 60 degree setting, full blast, engine on at 2K RPM.

You have provided the 2nd readings.
If the scroll control valve / compressor is the issue, then the low side will be 55+ PSI, and the high side will be below 150 PSI. (at idle)
If the engine fan were the issue, then the high side would be will over 250 PSI. (at idle)