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Dealer's appointment was today, system was slightly undercharged, they evacuated and added the exact amount required, it was 72 degrees out but the air felt colder, I hope it is fixed.
I wonder if they are using actual R-134A or a drop-in like R1234ze(E). R134A is banned for new car systems, but only recently. But since the 134A phaseout is recent the cost hasn't exploded yet.
I wonder if they are using actual R-134A or a drop-in like R1234ze(E). R134A is banned for new car systems, but only recently. But since the 134A phaseout is recent the cost hasn't exploded yet.
It kinda has, used to be $4.25 at Wally World, now it's $9.88
Couple of things to do BEFORE you spend money and throw the parts canon at the problem. #1/2 are free and easy.
1. Remove the front fan and clean the EVAP coils. They get dirty. Especially if you drive dirt roads and/or have a diesel. My boot blew off and my entire area under the dash is sooted over. The Evap coil was utterly clogged with nasty black/oily dust stuff. Air could barely flow through it. I used a garden hose and literally sprayed it out. Over and over. Then I used a mix of alcohol and soapy water to soak. Then sprayed it out again. It took 3 different tries before I finally got the thing clean. All the water drains out via the AC drain and onto the frame. You should not get any water in the cab (passenger floorboard) unless the drain is clogged.
2. Check the air gap on your compressor clutch. over time, the start/stop of the clutch wears down the mating surfaces as the spinning friction occurs. It's had ~20yrs of wear/tear. This increases the distance between the pulley and the compressor mating surface on the clutch. Air Gap. As this distance gets larger, the magnet that engages the clutch has a harder time attracting the clutch pieces together and syncing the compressor speed with pulley speed. Things start to slip. The compressor starts spinning slower than the engine. You can remove the bolt and there will be shims under it. Remove 1 shim (thin thin washer) and put the bolt back. This shortens the air gap and can effectively restore to normal measurements on worn units.
3. Check system pressures. Using the chart above, reference pressures vs temperature. You don't need to know the charge level. That's only needed when you're doing a evac, fill, or trim charge. To get you ballpark charge. If you don't have gauges, Autozone "rents" a kit. You buy the kit, use it, then return for a full refund. They have vacuum pumps as well.
Thanks again Tylus, I was able to go through all 3 of these steps.
I cleaned the box with compressed air, it looked pretty clean on the inside portion of the box. I also removed a single shim from the Compressor clutch.
Reading the gauges, Im getting around 70 on the low side and just over 200 on the high side. So, it looks like I have a High low pressure reading, and a Low High pressure reading. Ambient temp was 93F.
Any thoughts ? The AC blows cold when while running over about 1500 RPM. At idle, the truck starts getting hot. Probe thermometer stuck in the vent reads 50F when running at high RPM, at Idle, the duct temp goes up over 60F Essentially, I have to rev the truck at a stop light to keep it blowing cold air.
I cleaned the box with compressed air, it looked pretty clean on the inside portion of the box.
I have to rev the truck at a stop light to keep it blowing cold
I highly recommend you go and clean the evap out with water. Literally use a garden hose. It may be clean on the surface, but keep in mind. There is a bunch of little bitty fins with small air gap between them, extremely easy for dirt and other debris to be hidden and impede airflow. It can really affect your heat transfer.
(Edit: see post below, low charge also does this) revving it to increase cooling actually makes me think you may have a water pump issue. Or a really dirty condenser. Or bad fan for the motor. You should see almost no difference in cooling at idle versus freeway speeds unless the temperature outside is blazing hot. If it is that hot outside, revving it a little bit won’t really help the issue.
Reading the gauges, Im getting around 70 on the low side and just over 200 on the high side. So, it looks like I have a High low pressure reading, and a Low High pressure reading. Ambient temp was 93F.
Keep in mind my experience is Commercial and Submarine HVAC. I dabble with Auto HVAC. Wanted to answer this seperately because you could have several issues and didn’t want them getting lost in the mix
Use the 95F line. Your suction is too high at 70# and roughly 100# low on discharge. That screams non-condensables to me. And low refrigerant charge. The non-cons (air) won’t condense and keep the system at a pressure higher than normal. Can’t compress what isn’t there, so low discharge because not enough Freon.
This is what I’d do. It isn’t “correct”. It’s a great go/no go. Then you can fix it properly later. I’d add a can of R-134. Just Freon. None of the lube/fix/snake oil stuff. Be around $10 for a 6oz can. Watch pressures and stop when discharge gets near 300#
if that fixes most of the issue except suction pressure, then you have a path forward. Evac the unit, replace the 2 inline filters, rear expansion valve, and desiccant, evacuate again, then recharge properly. You can do all of that at home for about $150 using all new Freon.
Was wondering because 6.0’s with 2006/2007 PCM strategies will have the fan quit working when EGR is unplugged. Your 2005 is likely to have the this strategy because Dealerships upgraded it anytime they worked on them. Looks like yours is installed and plugged in.
even with the clutch shroud missing it should still have decent air flow across the rad/condenser. The actual fan shroud is still there
@Tylus Thanks for all your help! Really appreciate it!
I finished the compressor swap today, I also replaced the dryer, orifice tube filter. I evacuated the system and charged it. It seems to be working better now, I'm seeing about 40 degrees inside the vent. Im going to take it out on the road and see how things work.
