Automotive Air Conditioning Information Forum

Afternoon all, I come to you with questions and for ideas.
Background, Im a light-duty Diesel Tech, 609 Certified, and have done a lot of AC system work as it's part of lifting the cabs and we do that almost every day.

I do not consider myself an AC Tech, but we have had success for years on Ford Super Dutys, Ram trucks, Excursions, and an occasional AC repair on other vehicles.
We currently have a Mastercool Commander 3000, current on filters and pump oil. And a Mahle ArticPro ACX2180 that is brand new, so current on filter and oil.
We do only R134.
The problem child(s) are my personal Excursion and two other Excursions we have.
All new system, TWICE in my 2003 Excursion which has rear Aux system. So both evaporators, expansion valve in the rear, and both variable orifice tube for high temp region and Red OT have been used (Im in central texas, and its at near or above 100 deg F) in the front, condenser, compressor, accumulator/dryer, filter in the rear suction line. Blend door is confirmed in the proper position, heater core in both front and rear bypassed. Lines flushed both directions and dried with nitrogen.
Vacuumed down to 29.6 in Hg for 60 min, leak checked for 20 min, total time under vacuum 80 min. The system charged with 14 oz PAG 46 (the compressor comes pre-charged with 3oz, so amount added by the machine is 11 oz and that was confirmed manually as well based on pre/post amounts of oil in the bottle) and 68 oz of R134 per the manufacturer recommendation>
A thermal scan of the condenser shows no blockage.
I have used both our older Master Cool, and the new Mahle to confirm it's not a new machine issue.
Yesterday it was 98 deg ambient on a wet bulb thermometer, LP was 55 psi, HP was 225 psi. I can monitor fan speed so know it is pulling air as it should, the radiator, intercooler and transmission cooler are all clean, and bent fins are very minimal. Wind speed measured with an Anemometer show I have almost no drop off front to rear of the cooler stack and all OEM air dams are in place.
All of that and Im getting 60 deg vent temps measured by both a standard AC temp probe and a second duel sensor reading digital thermometer.

Im missing something clearly..But what? With low side in range, but high side a little low
Thanks

Erik In Texas, sweating profusely

EDIT : I looked at the notes, and updated the LP & HP to what they were yesterday

Oh and to motivate ..... I just made a $10 donation for the Yearly site maintenance donation fund (the first donation of the fund drive), and with your help, if I can see mid-40s vent temp, I'll donate another $40. Anything below 40 deg and I'll donate another $20.

Thanks for helping in advance

Erik

Had an hour to kill, so evacuated and confirmed the charge, 68 oz per spec. vacuumed at 29.5 for 30 min (never opened the system but just to give it a chance at boiling off noncompressible's), charged at 68 oz and......resulting in 61deg f vent temp at idle with fan clutch locked up, 57 deg at speed. Ambient temp 94 deg f.

Your specs match what I have: 68 ounces net weight of R-134a, and 14.0 fluid ounces of PAG-46.

Have you tried running the system at an engine speed of about 1,800 RPM with the rear A/C turned off while checking the front center vent temperatures?

Are you sure you have the correct amount of oil in the system? Too much oil can insulate the interior of the evaporators and prevent proper cooling.

What type of OT do you have in it now, the VOV or the fixed-orifice style?

All of us here on the forum appreciate your donations, Tim, the site owner in particular. We have a strong forum with sharp, experienced consultants, and wish to keep it that way!

Erik In TX wrote: ↑Sat Jul 20, 2024 12:28 pm Oh and to motivate ..... I just made a $10 donation for the Yearly site maintenance donation fund (the first donation of the fund drive), and with your help, if I can see mid-40s vent temp, I'll donate another $40. Anything below 40 deg and I'll donate another $20.

Thanks for helping in advance

Erik

Suppose everyone who has benefited donated $10.00 for the help they received. All while buying products off the internet from every source except ACKits.com. They could not only maintain status. Maybe even add some improvements.

Thank you very much.

JohnHere wrote: ↑Sat Jul 20, 2024 2:05 pm
Have you tried running the system at an engine speed of about 1,800 RPM with the rear A/C turned off while checking the front center vent temperatures?

Yes, at 2,000 rpm I got down to 55.6 deg

JohnHere wrote: ↑Sat Jul 20, 2024 2:05 pm Are you sure you have the correct amount of oil in the system? Too much oil can insulate the interior of the evaporators and prevent proper cooling.

Yes, absolutely positive on the last three tries.
Evac, all new components (yes everything, both evap, compressor, condenser, accumulator/ dryer, manifold line, rear expansion valve, front OT and rear filter in the suction line..so all new but the physical lines front to rear), flushed lines, vacuumed down 60 min at 29.5, compressor stated it came with 3 oz, added 11 for total of 14 oz, charged 68 oz r134

Evac, machine removed 1.2 oz, vacuumed down 60 min at 29.5, added 1.2 oz, charged 68 oz r134.

Evac, all new components, flushed lines, drained new compressor of 2.8 oz, vacuumed down 60 min at 29.5, added 11.2 oz.

JohnHere wrote: ↑Sat Jul 20, 2024 2:05 pm What type of OT do you have in it now, the VOV or the fixed-orifice style?

1st two times I had a standard red fixed OT
Last time I tried a variable orifice OT, no change


So large system, perhaps 60 min at 29.5 is not long enough to remove all noncompressibles and moisture?

I would have assumed the superduty with same engine, and Excursion with no rear AC would use the same compressor, but the Excursion with rear AC would use a different compressor. Can not confirm with now part numbers as it is a discontinued item, Aftermarket makes no distinction between with or without rear AC...but my brain says it should be different to handle the additional size of the Excursion dual system, the condenser as well. Thoughths?

High side pressure is a little low. low side about spot on, and static pressure matches ambient temp. Still with low HP, perhaps a little undercharged regardless of spec?

Thank you for your time.

Am I missing where the engine size is listed for these Excursions? Better yet, post the VIN.

Tim wrote: ↑Sat Jul 20, 2024 6:00 pm

Erik In TX wrote: ↑Sat Jul 20, 2024 12:28 pm Oh and to motivate ..... I just made a $10 donation for the Yearly site maintenance donation fund (the first donation of the fund drive), and with your help, if I can see mid-40s vent temp, I'll donate another $40. Anything below 40 deg and I'll donate another $20.

Thanks for helping in advance

Erik

Suppose everyone who has benefited donated $10.00 for the help they received. All while buying products off the internet from every source except ACKits.com. They could not only maintain status. Maybe even add some improvements.

Thank you very much.

Thanks, Im happy to give back to a community helping others and myself.

As an industry insider...a question, on another forum restricted to verified shop owners... One shop owner who was struggling with a same-generation F350 as this Excursion claimed, he cut away a OEM Motorcraft condenser and a Murry from Orilies (same brand Im using for now) and found the channel size in the Murry to be much smaller than the channel size in the OEM condenser. He sourced a good used OEM condenser (discontinued by Ford) was flushed well, ensured fins were as straight as he could get them, installed and serviced as he had been previously, and instantly measured a 20 deg lower temp with the only change being the condenser.
A: Does that make any sense to anyone?
B: Does ACKits sell a condenser for a 2003 Excursion with 6.0 Powerstroke that you believe exactly matches the design standards of OEM?

Man, you're going to make me fire up the corporate computer. Let me run down, drop off my ballot, and get some dinner. Recent spine surgery has had me laid up. I'm just starting to get moving again and want to at least do these things. I'll fire it up and check availability in a little while