2004 freestar 4.2L ac issue
 

I was wondering if anyone has had issues with the ac, this is what happens at 60mph it is cold at a idle or low speed it blows hot, I researched this out and it appears it could be the scroll compressor valve, but I am not sure they have this part for my year van-has anyone had this issue and that was it?

Any other suggestions?

A good part of the time when the system is low on refrigerant you get what you are getting. Do you have any means to add R134A refrigerant? Depending on where you live the A/C need is declining as fall is just around the corner. If you need to add to the system , just take the usual safety precautions goggles etc., and get a kit with a can of 134 and add it to the low side of the system. The fitting will only fit the correct fitting on the vehicle. You connect the fitting when the a/c is operating that way the low side pressure is lowest then add the refrigerant with the can right side up so the refrigerant goes in as a gas. If the system cools somewhat better at low engine speed that would confirm the need for addl refrigerant. Just don't go overboard, this is one of those things where more is not always better. Let us know if you decide to try this.

ac
 

My husband hooked up a guage and it said the freon was on the high side is why we don't think its that-Yesterday when it was 90 out I started it and let it idle and it seemed to work. I tried shutting off the recirculator and it seemed to work better without it on-today i have to go to town and it will be 92 degrees so we will see how it works-if i sweat to death:eek: or am happy when i get home:)

If you have the proper gauges for R134A , could you tell us what gauge readings you found and what was the engine speed and ambient temp. The system should cycle a couple of times a minute when the system is right and functioning correctly, does it?
(Cycling refers to the compressor clutch coming on and turning off)

ac
 

It did not work at all yesterday so I sweated-We just have to do some testing on it, my brother in law has some more advanced gauges we can get if ours don't work, but time is an issue-I will let you know what happens when he has time to check it out

he hooked up the gauge that comes with the freon-and it was in the red at 85lbs and he was hooked to the low side-my dual gauges were loaned out-when u rev the van way up to 4500 rpms the van ac lines would get cold instantly, and the pressure would come down into the yellow-55lbs-and it would blow cold air- soon as it idles no cold air-pump continues to run constantly even at idle-no cycling, seems noisy-and heavy strain on motor
he is guessing plug or bad pump-will hook up good gauges this weekend-any thoughts?

Yes, if the system is overcharged it won't cycle, puts a heavy load on the compressor and doesn't cool as it should. Before condemning the compressor best to get actual gauge readings.

Here's a starting point with a couple of questions. Hope it makes sense as I tend to ramble at times.

1st, you don't have a scroll compresser. It's a 5-Dual Piston wobble plate compressor. Do you have just front A/C or dual (Front/Rear) A/C? Sounds like the system is overcharged. Has anybody added any R-134a to the system? If so, was it plain R-134a, or did it have an oil charge in it? If an oil charge, you can slug the compressor with too much oil and ruin it. Pluss you could then be pushing too much oil thru the system with the R-134a and causing orifice plugging. Being that your ambient temperature is 90-92°, with a set of gauges on the LOW and HIGH Pressure ports and the engine off and cold (you want no engine heat affecting your static pressure reading), you should be reading about 105-110 PSI on the LOW and HIGH side. With the engine running and the A/C on and an ambient temperature of 90-92°, you should have a reading or 45-50 PSI on the LOW side and 250-270 PSI on the HIGH side. A restricted orifice will usually show as very low suction side pressure and lower than normal high side pressure. if your gauges are reading You really need to get a set of gagues on it and set the RPMs to 1500 RPMs to take your readings.

If the compressor is on it's way out. it will show the inability to generate enough suction and pressure at or near idle speeds. If engine speed needs to be substantially increased to bring pressures in range (Your 4500 RPM that you mentioned), that's a sign that the compressor is getting weak. Common symptom complaint is... only cools when the engine is reved - or - only cools when driving down the road (As you have mentioned).
Sometimes it's very simple. If you hook the gauges up and were to see say 80 psi on the low side, and 80 psi on the high side, and the compressor is spinning, it's likely that compressor is done. It's not producing suction, and it's not producing pressure.

However, you can't diagnose or determine anything without a set of gauges on the system.