AC blows cold, then warm and cold again!

[daisyrocky]

Hi everyone, wonder if this happened to any of you. 1997 Explorer 4.0 with auto climate set at 66 degree, blows real nice cold air. After 30 minutes of driving, it blow warm air but I did not cut off the air and let it blow warm air for another 10 miles of driving then ice cold air came back on itself. One thing for sure is the 134a never leaked out or else I would not have cold air back on? This happened twice in 10 days. Any inputs is deeply appreciated.

 

[Alex7772011]

Low on gas or compressor is no good. get gauges hooked up low side should be around 30-35psi (the blue). if you dont have gauges open all your window's turn on your ac and put it to max and stick a thermometer into one of the vents if its blowing around 40-50 should be fully charged if not you low on 134.
when you low on gas the compressor will click off when you putting load on the engine.

 

[GTMountain]

Or, clutch could be disengaging but I agree it's likely just low pressure. If you don't want to spring for a can with a gauge the thermometer test will tell you if it's pumping full cold.

 

[Alex7772011]

Or, clutch could be disengaging but I agree it's likely just low pressure. If you don't want to spring for a can with a gauge the thermometer test will tell you if it's pumping full cold.

its low on gas for sure. the gauges is expensive and not worth it to have it unless you work on ac systems all the time. do the thermometer test, but rev up the car once in awhile to see the temp

 

[TxBucki1]

I have the same issue on 1998. This morning, blows cold, then after some driving, at stop, it warms up, then when I get back going (like ~50 mph or higher), gets cold again. I read gauges yesterday and Low = 47, High = 225. It was about 90-95 degrees at the time. (seems like this should be about right). Sounds like either

 

[TxBucki1]

I have the same issue on 1998. This morning, blows cold, then after some driving, at stop, it warms up, then when I get back going (like ~50 mph or higher), gets cold again. I read gauges yesterday and Low = 47, High = 225. It was about 90-95 degrees at the time. (seems like this should be about right). Sounds like either

Compressor or possibly clutch?

 

[Motorhogman]

I have the same issue on 1998. This morning, blows cold, then after some driving, at stop, it warms up, then when I get back going (like ~50 mph or higher), gets cold again. I read gauges yesterday and Low = 47, High = 225. It was about 90-95 degrees at the time. (seems like this should be about right). Sounds like either

Understanding Normal AC Pressure Gauge Readings

Learn why normal AC pressure gauge readings are essential for diagnosing car AC problems. Don't rely on just the low-pressure gauge

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[C420sailor]

Check your fan clutch. If your fan clutch is shot and the fan isn’t pulling air through the condenser while the vehicle is stopped, AC efficiency will drop.

 

[Turdle]

I have the same issue on 1998. This morning, blows cold, then after some driving, at stop, it warms up, then when I get back going (like ~50 mph or higher), gets cold again. I read gauges yesterday and Low = 47, High = 225. It was about 90-95 degrees at the time. (seems like this should be about right). Sounds like either

You might want to check coolant level

 

[TxBucki1]

Added about 1/2 gallon coolant. I’ll see on way to work tomorrow. Did static gauge reading: 100 degrees under hood. Low was pegging out 250….high was about 130. That seems strange huh? It was sitting around 2+ hours.

 

[C420sailor]

Something is VERY wrong there

After a couple hours at 100°F, static pressures should be equal at about 125psi.

 

[TxBucki1]

Went to check again about 4 hours later and it evened out. Interesting though, when I take off cap for low side, it hisses. Sounds like new compressor/dryer after blowing out system..

 

[TxBucki1]

Pressure switch maybe?

 

[donalds]

My vote is for the fan clutch
Is the fan kicked on the numbers with drop to normal

 

[TxBucki1]

Not sure what you mean:
Is the fan kicked on the numbers with drop to normal

“On the numbers”?

 

[C420sailor]

Your high and low side pressure numbers

 

[TxBucki1]

Just went outside (it's 90 degrees) and tried to spin fan by hand..it moves about 2 blades (not much). is this normal?

 

[Turdle]

Others may say I'm wrong, but mine spins with slight resistance.

Severe duty fan clutches might "grab" more.

If the clutch was frozen though I d think the fan would sound like a airplane taking off.

 

[donalds]

Plenty of videos on how to test the fan I'd look into em

It should not spin that easy at all