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I have been having a lot of air-conditioning issues over the past couple of years.
First off, the Vacuum pump died, and im looking for a recommendation on replacement ? Do most of you guys use the Dorman pump ?
Also, Im not sure what the AC pressures should be, as its a dual zone truck. The previous owner must have removed the decal with the pressures under the hood.
It seems to cool until it gets really hot (im in Texas), and then it just cant keep up. Its blowing sort of cool, just not cool enough
Mix hot temps with AC only coming out of the defroster vents, thanks to the Vacuum pump
I chased it around fixing parts, until my compressor failed, and ended up king all the components for a full replacement.
I have a Dorman vacuum pump, but I’d go with the cheapest unit I can find on Amazon Warehouse. It won’t hurt anything.
Pressure isn’t going to help you, unless you can verify the system is fully charged. The system with Rear Aux requires 58oz of 134a. The only way to measure this is to remove all the refrigerant and pull a vacuum and refill new 134a. Then, the pressure can be checked with a 134a pressure chart and current ambient temperatures.
I am very pleased with the results, using a combination of after market parts from GPD, Four Seasons, and UAC.
The parts were mostly off Amazon warehouse parts, and some from Rock Auto.
Before I cracked open the system, I had a shop recover the refrigerant. Their rig pulled out about 40oz, so I had a leak somewhere that exacerbated the issue. (paid them $15 cash. For the work…)
I spent the next week replacing everything in my spare time.
new compressor and belt (old one was different length)
new evaporator
new front condenser
new rear condenser
new drier
new orface tube
new expansion valve
new rear refrigerant filter
new mixture motor in front
new o-rings
new vacuum tube (heater core bypass line)
14oz PAG 46
58oz 134a
I found debris in the lines, clogged condenser coils, bad vacuum lines, stripped fittings, loose foam on mixture panel in rear, and a bad mixture motor in the front.
I also replaced the rear heater core, while I had it open. But found cracked coolant/heater tubes under the body that I’ll fix later on.
There is a orface tube in the front to regulate refrigerant, and an expansion valve in the back for the Aux AC. ALSO, Right after the small refrigerant tube turns upward towards the rear, there is a $2 in line filter. Mine was completely clogged. Make sure you replace this after flushing the lines.
Poured in oil, pulled a vacuum, verified it held, and then loaded the 134a.
it works like a champ now! New vs old New vs old Rear filter Orface tube
Wow! thanks for all of the info Critter!! Really appreciate the detailed response. I think I am having the exact same issue you were having.
It seems when I rev the truck on really hot days, the AC blows colder, which tells me compressor. I think its the stock compressor. I am also not 100% sure I dont have a small leak somewhere.
Thank you for providing the amount of 134a to use!!! I couldn't find a straight answer anywhere on the correct amount!
Did you just go with an OEM compressor replacement ?
Yeah I just keep buying the Amazon Vac pumps, they seem to last a year or so....I think I have a vacuum leak somewhere.
Overall, I was considering selling the truck because of little issues like this cropping up. But after pricing the new F250s, I think im just going to dress it up some, and keep it for awhile.
Also, Im not sure what the AC pressures should be, as its a dual zone truck. The previous owner must have removed the decal with the pressures under the hood.
First off,,nice screen name, how strange is it that two people named Anton both own 2005 diesel Excursions, and both live in TX.
Second, refrigerant pressure changes based on outside ambient temperature at the time. There is no set pressure, it's a chart. Google search for 134A temp pressure chart, plenty will come up, below is just one example.
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.
For #3, I have the gauges, and I have checked the pressure several times, and it falls in the normal ranges based on the chart above. Its only when it gets Texas hot outside (over 95 degrees), it cant seem to keep up, and the truck starts getting hot. It seems to be worse at lower RPMs, it seems to help to rev the truck a bit when stopped.
To your point, I havent checked the evaporator, for all I know, there maybe an old walmart bag covering it!
310...????
That's high, especially for the ambient temp.
50 on the suction seems high too.
I have had to go between 2 shops, the last one did not have the machine to add the refrigerant by weight. I am going to call the dealer who did the compressor in November and have them recheck the charge now that it has warmed up, not mentioning the 2nd shop that did the evaporator. Baby steps but fixing an A/C system should not take 5 months.
I have had to go between 2 shops, the last one did not have the machine to add the refrigerant by weight. I am going to call the dealer who did the compressor in November and have them recheck the charge now that it has warmed up, not mentioning the 2nd shop that did the evaporator. Baby steps but fixing an A/C system should not take 5 months.
I agree, if you recall, I have opened up mine 3 times for repairs, voluntary replacement parts, and once so I could move the front Evap box out of the way so I could get the injectors done. Do you have Freon? I have a scale, not sure how much 134A I have currently, it's being phased out too. I think I'll need to buy one more 20lb jug before I retire. Your pressures could be a result of over charge.
The problem will be when you have ambient temps above 90, and at or above 100, you may trip the high pressure cut out, or activate a high pressure blow off, but I don't think we have those, I don't remember seeing one.
I agree, if you recall, I have opened up mine 3 times for repairs, voluntary replacement parts, and once so I could move the front Evap box out of the way so I could get the injectors done. Do you have Freon? I have a scale, not sure how much 134A I have currently, it's being phased out too. I think I'll need to buy one more 20lb jug before I retire. Your pressures could be a result of over charge.
The problem will be when you have ambient temps above 90, and at or above 100, you may trip the high pressure cut out, or activate a high pressure blow off, but I don't think we have those, I don't remember seeing one.
Appointment set at the dealer, I told them I wanted the system to be evacuated and the exact amount called for to be put in. Unfortunately the 23rd is the earliest I can get it in.
