A/C woes

[OBS-Addiction97]

Bought the truck back in dec. it's a 15 and I've been having more issues with it than I'd like. Since it wasn't so hot out until now I didn't notice much of an issue with the Ac.

I just had a buddy hook it up to his Ac machine to check the charge. It was low so it was filled to factory spec. Oddly enough it ls warmer at cruising speeds now than before I brought it to him, but it's colder at idle now.

My issue is while accelerating/crusing I can feel the compressor kick off and on. It's basically warm/cool/warm/cool. It never gets ice cold at highway speeds. At idle it's cold as can be. As soon as I'm moving it starts getting warmer. It's acting like it's over charged almost. Truck had 65k on it.

Anyone have any suggestion where/what to look for before I replace every component. I have basic gauges and AE.

 

[jimdawg185]

Sounds like a compressor issue. But maybe someone with more expertise will chime in.


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[jimdawg185]

Or a sensor


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[OBS-Addiction97]

Sounds like a compressor issue. But maybe someone with more expertise will chime in.


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I wonder if the clutch is slipping under load.

 

[OBS-Addiction97]

Idling pressures:

Low- 30 psi
High- 200 psi

Ac on max and 85-90* ambient.

After idling for 5 minutes

Low- 26 psi
High-180 psi

Pressures seem low for how hot the ambient temps are.. but I'm not an expert.

 

[04cr450]

Pressures are low. You have a leak. Vapor side (low) should be roughly 55 psi on that outside temps and on the liquid side (high) you should see roughly 250 psi
The compressor engaging and disengaging is your low psi switch cutting in and out.

 

[OBS-Addiction97]

Pressures are low. You have a leak. Vapor side (low) should be roughly 55 psi on that outside temps and on the liquid side (high) you should see roughly 250 psi
The compressor engaging and disengaging is your low psi switch cutting in and out.

It was just charged to factory spec today. Should I add some more freon in? I do agree that the pressures are low from what I've seen in the past. I don't necessarily like charging by pressures only but I guess don't have much of a choice right now.

 

[04cr450]

Yes u can refI'll it since it is not a blend refrigerant. Add refrigerant (do vapor so it's doesn't get away from you) and see what happens. If pressure come up and your delta T temperatures spread farther apart to 20 or so degrees (air coming out of supply vents and cabin space temps), then you are on target and found the issue

 

[OBS-Addiction97]

Also, any common spots these trucks leak from? This thing is too new to be having these issues. Dang fords.

 

[04cr450]

Btw don't always trust charging scales- a good psi temp(pt ) chart and thermometer never fails. You also must charge by pressure and temps not always by weighing it in. That is only correct true way of charging a refrigerant system

 

[OBS-Addiction97]

Btw don't always trust charging scales- a good psi temp(pt ) chart and thermometer never fails. You also must charge by pressure and temps not always by weighing it in. That is only correct true way of charging a refrigerant system

I took it to a buddy's shop. He hooked it up to one of the automatic recovery machines. Would that still undercharge it?

 

[04cr450]

Also, any common spots these trucks leak from? This thing is too new to be having these issues. Dang fords.

This I am not sure but... check any joints that have seals in them you will see an oily residue around the joint.

 

[04cr450]

I took it to a buddy's shop. He hooked it up to one of the automatic recovery machines. Would that still undercharge it?

Of course.. it's electronic and can fail, auto techs are not refrigeration guys- they put all the trust in the charging machine. It happens, check your pressures and temps manually and go off the pressures I said if the outside ambient temps are still at 90. Pm me... if outside temps are lower when you are checking and I can tell you what the psi's should be at

 

[04cr450]

Basically when your refrigerant pressures are low, you are not getting a full column of liquid going to the orifice before reaching the evaporator coil, ie: no subcooling. You need a full liquid column of refrigerant to create this and have a saturated vapor going to the evaporator coil. Which to make this short drives the refrigerant pressures up esp on the high side. Where your psi's are at now at that high outside temp- there is zero to little subcooling and the system will not efficiently operate

Disclaimer: if you add refrigerant and yourn pressures do NOT come up.. you have other issues associated in the system. I can walk you you thru this as well but let's start off with the obove

 

[OBS-Addiction97]

Thank you for your help. I'll give it a shot Sunday and report back.

 

[8WR_ZJ]

04cr450 is giving solid advice. At our "offroad shop" we do lots of drivetrain repair. Then we did a few ac job for some friends and good client. It jas evolved into a more normal thing now. We will add by the factory spec but always watch the pressure readings. We have a chart taped to the side of the machine. Idk why but most of the ford specs are low for us. Gm seems to be the most accurate. The only 6.7 powerstroke we have done was on a motor swap idk of any leak points. Sorry

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[OBS-Addiction97]

Added some freon today.

95* out side

Low- 28
High- 260-270

Pressures seem to be fluctuating on the gauges 2-4 psi.

 

[8WR_ZJ]

What is the vent temp? Still seems low psi on the low side of the gauge. Does the clutch still cycle?

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[OBS-Addiction97]

What is the vent temp? Still seems low psi on the low side of the gauge. Does the clutch still cycle?

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Clutch says engaged 100% of the time while it's idling. I'll have to find my vent thermometer and check it. Still seems like the clutch is cycling off when I'm driving. Its working a bit better after I charged it today, but I ageee the low side still seems low.

I didn't want to keep adding freon since the highside was getting up there.

 

[04cr450]

Added some freon today.

95* out side

Low- 28
High- 260-270

Pressures seem to be fluctuating on the gauges 2-4 psi.

You have a restricted orifice/metering device which is located on the liquid/high side of circuit... it's not low on refrigerant.
Need to recover refrigerant, replace orifice, pressure test with dry nitrogen, evacuate to 500 microns, charge to specs. You will be good to go
Note: you may also have a plugged evaporator coil which would cause low vapor psi. But seeing your high side is out of range and high leads to a common problem of a clogged orifice