Automotive Air Conditioning Information Forum

I have a 2007 Ford escape hybrid and the AC has been just blowing cool not cold so I thought maybe it was just low on refrigerant but I went and got AC manifold pressure gauges and wow. With engine off the hi and low are both at about 100 psi. If I start the car (completely warmed up already) both hi and low go up to about 125 psi then gradually settle back to about 100 psi. If I close the hi and leave the low open they both drop to about 50 psi and gradually settle to about 40 psi. If I close the low and open the high they both go to about 125 psi and stay there. If I close both they both sit about 50 psi and stay here until I disconnect them then they both drop to zero psi. Oh also when both the low and hi are open, or just the hi, you can see coolant circling in the yellow hose window but none circles in there if just the low is open. I'm completely baffled. Does anyone have any idea what's going on? Any suggestions or other things I can check? Any help would be greatly appreciated.

A couple of things I noticed when researching your vehicle is that the compressor, a scroll-type, is engine/motor driven in the conventional manner by a serpentine belt and magnetic clutch.

Additionally, you shouldn't open and close the Manifold Gauge Set handwheels if all you want to do is measure system pressures. The only times the handwheels on a MGS should be opened is during evacuation (engine off, both LS and HS MGS handwheels fully open, service port adapters fully open [thumbwheels turned fully clockwise], and the yellow hose connected to a vacuum pump); and charging (engine running, LS MGS handwheel fully open, HS handwheel fully closed, and the yellow hose connected to a refrigerant source).

Even with the MGS handwheels fully closed and connected to the service ports with the adapters fully depressing the Schrader valves (thumbwheels turned fully clockwise), you'll still be able to measure pressures on both the LS and HS.

In a nutshell, here's the testing procedure that's most often discussed on this Forum: Note the ambient temperature in front of the grille (not the temperature provided by the local weather report), raise engine RPM to ~1,800, set A/C to Max, set the blower to Medium, set the air outlets to the Dash Vents (not Defrost, Mix, or Footwells), place a stem thermometer into the center dash vent, and open all the doors and windows. What you will be doing is maximizing the heat load on the system for an accurate performance test. Then record and post the LS and HS pressures, as well as the center vent temperature and ambient.

It could very well be that it's just low on refrigerant, especially if the system has never been serviced since new.

Visually verify that the AC clutch drive plate is engaging, turning at the same rate as the outer belt-driven pulley.

It is a 17 year old system with a scroll compressor.

I would recover the system and weigh the charge removed. Then inspect the orifice tube for debris.

Cusser wrote: ↑Fri Jun 07, 2024 6:46 am Visually verify that the AC clutch drive plate is engaging, turning at the same rate as the outer belt-driven pulley.

Yes it is.

JohnHere wrote: ↑Thu Jun 06, 2024 9:19 pm ...you shouldn't open and close the Manifold Gauge Set handwheels

...set A/C to Max, set the blower to Medium, set the air outlets to the Dash Vents (not Defrost, Mix, or Footwells)

It could very well be that it's just low on refrigerant, especially if the system has never been serviced since new.

I wasn't turning the handwheels just the dials on the ports that depress or retract the plungers.

When I set it to AC max it turns the blowers on high and decides which vents to use (all of them I believe) on its own I don't have control of blower speed or which vebta at that point.

If it might just be low on refrigerant why would the low pressure and the hi pressure both be at 100psi with both valves open? Shouldn't the low be around 35-45psi (lower if low in refrigerant) and the hi be around 185-215psi?

I think we have a terminology issue.
There are two sets of wheels. One set on the MGS itself. These should be both closed unless you are vacuuming or adding refrigerant. They do not need to be open to read system pressures.

The other set is on the so called quick couplers that snap onto the ports on the car. These are at the far end of the hoses away from the MGS. The ports have shrader valve cores, and to read system pressures, or to vacuum the system, or add refrigerant, these thumb wheels need to be tightened down to depress the shrader core.

I am having trouble following just what you did. Keeping the normal function of the parts in mind, and John’s comments in mind, please describe again what you did. We are here to help in any way we can.

Edit: I just clarified some terms

SoulSnatcher wrote: ↑Wed Jun 12, 2024 12:58 pm I wasn't turning the handwheels just the dials on the ports that depress or retract the plungers.

I wasn't clear whether you had the MGS handwheels fully closed and the service port adapter thumbwheels turned fully clockwise when taking your pressure readings. I'm still somewhat unsure about that.

SoulSnatcher wrote: ↑Wed Jun 12, 2024 12:58 pm When I set it to AC max it turns the blowers on high and decides which vents to use (all of them I believe) on its own I don't have control of blower speed or which vebta at that point.

When you set the A/C to Normal (or whatever Ford calls it), can you then control the blower speed and which vents the air blows from?

SoulSnatcher wrote: ↑Wed Jun 12, 2024 12:58 pm If it might just be low on refrigerant why would the low pressure and the hi pressure both be at 100psi with both valves open? Shouldn't the low be around 35-45psi (lower if low in refrigerant) and the hi be around 185-215psi?

Those pressures don't make sense to me. Did you record 100 PSI on both the LS and HS with the engine running and compressor engaged, or with the engine off?

Regardless, the only definitive way to determine whether it's low on charge, charged to specifications, or overcharged is to recover the refrigerant that's in the system now (or have it done by a professional MVAC shop), note how much refrigerant the A/C machine reclaims, and compare that result to Ford's specs.

If you're going to recover the refrigerant, you might as well remove the Orifice Tube, as suggested earlier, and examine it for black gunk, metallic shards, and plastic particles. If you find the OT partially or fully obstructed with that kind of debris, the scroll compressor is disintegrating internally.

Does your vehicle have an A/C-cooled battery compartment in the rear? If so, have you changed the intake air filter in that compartment, and also the cabin air filter?