My A/C Stop blowing cold air after 45 mph

[vitorio]

My Taurus 1995 (180,000 miles) A/C stop blowing cold air (keep blowing hot -ambient air) after 45 mph speed.

After the speed is lower than 45 mph returns to blowing cold air and A/C keeps working fine.

Visit various a/c license stores but received diverse opinions about how to fix it.

Opinions as

- replace compressor
-clutch do not engage
-low pressure
-replace the condenser/evaporator
-some do not heard this issue before

Please help me with your thoughts about what may be the issue and how a tech can test it to find a solution.


Thanks for the help.

PS compressor is new around 1 year
change A/C cables around 1 year
evaporator is the OEM that came with the car
do no remember if changed the condenser

[Tim]

My guess is with limited information. It is shutting off due to high pressure.

[vitorio]

Coul it be the expansion valve?.

This is my logic, since The expansion valve maintains the pressure difference between the condenser and the evaporator. For my Taurus 1995 Expansion Valve A/C Orifice Tube.

high speed high pressure, then compressor stop working
Low speed low pressure, then compressor works again

Comments welcome

Thanks.

[JohnHere]

I agree with the previous suggestion that the problem is likely due to high pressure. An overcharge could be one of the reasons for that.

The first thing to check is whether you have the correct amount of refrigerant in the system, which would require recovering and weighing it. A professional shop having a Recover/Recycle/Recharge (RRR) machine will be able to tell you that, as long as you don't have any alternative refrigerants, mixed refrigerants, and/or sealer in the system.

All USA-produced 1995 Ford Taurus vehicles have the following A/C specifications: 32 ounces net weight of R-134a, and 7.0 fluid ounces of PAG-46. If your vehicle has an under-hood decal with specs that differ, the decal takes precedence.

The metering device in USA-built cars is an Orifice Tube (OT), not a Thermostatic Expansion Valve (TXV). It's possible that the OT's screen is plugged or partially plugged, which will also raise the pressure on the high side to the point of tripping the high-pressure safety switch and shutting off the compressor.

Have you owned this car since new, and do you know the service history of the A/C system?

[vitorio]

Do you need to remove the he evaporator to replace the Orifice Tube (OT) for a Taurus 1995?

Thanks for the help.

[Cusser]

The first thing to check is whether you have the correct amount of refrigerant in the system, which would require recovering and weighing it. A professional shop having a Recover/Recycle/Recharge (RRR) machine will be able to tell you that, as long as you don't have any alternative refrigerants, mixed refrigerants, and/or sealer in the system.

This a terrific suggestion, and I recommend this path highly.


Have you owned this car since new, and do you know the service history of the A/C system?

[JohnHere]

Do you need to remove the he evaporator to replace the Orifice Tube (OT) for a Taurus 1995?

The OT should be somewhere inside the metal liquid line (the thinner of the two lines) in the engine compartment. On your car, I can't recall whether the OT is permanently installed in the line or whether it's removable and therefore, replaceable. I suspect it's the latter.

Look for a threaded joint and a couple of dimples in the metal tubing. Those indicate a replaceable OT's location. A new one is only a few U.S. dollars. But if you pull it out and it's full of black gunk and other debris, then you have additional work to do.

[Tim]

John, it's in the liquid line.

[tbirdtbird]

Could this be the clutch