2004 AC not working

Have a 2004 2.7L 4x4 I bought last week. AC compressor was locked so I replaced that today. Put about 7.75 oz of the 46 oil in the compressor then installed. Vacuumed the lines for an hour. Added roughly 20oz Freon. AC won’t blow cold on high. If I fiddle with it in low it’ll blow slightly cool. Connected the pressure lines and my low side is reading about 130 psi and my high side is reading 150psi. Any ideas on the next step? Swap out condenser and dryer?

 

I'm having a hard time believing your pump is turning on. The low side seems pretty high.

 

Koditten, the compressor clutch turns on as it should. Sometimes blows cool if I mess around Temp knob on low fan speed

 

Blend door not working right?

 

I think it’s working fine. Air gets hot when I turn to the heat. But I can’t get cold air on any of the other fan settings

 

That would say its stuck and not opening to cool, just my guess

 

0% chance the low side would or should be 130 psi if the compressor clutch is engaged and the compressor is pumping freon. You won't hear the compressor clutch engage until about 13oz's +-1oz enters the system. You'll audibly hear the compressor clutch engage when system has enough minimum pressure to operate. Easy way to make sure your clutch circuit is good is to apply 12v directly to the compressor. Being that your compressor is brand new it's pry not likely to be the clutch circuit. The other two things that you'll need to rule out are the pressure switch and expansion valve on the evaporator. If the compressor grenaded in the system and you only replaced compressor it is likely you have a blockage in either the lines, accumulator/drier, condenser or expansion valve/evaporator under the dash behind the glove box. Depending on where you live, basically the low side is going to be somewhat close to the ambient temp without the truck running and the low side gauge hooked up. I just did my 4th AC repair on my GF's 2011 Honda Civic and the low side with system charged but car not running was pretty close to the ambient temp that morning of 110 degrees here in Phoenix. As soon as you turn AC on and the clutch engages the compressor you should see the low side come down to about 35 to 38 psi. Really the only true way to know how much freon you're putting into the system is to weigh it on a food scale as you're putting it into the system. Otherwise you can get pretty close by staying in the 35 psi area. I was able to get a FSM for the 11 Civic and read that it should be near 38 psi cold side when the system is charged. The only other thing it could be is the actual switch itself that activates 12v to the compressor. If you apply 12v to the single pin connector on the compressor and complete the circuit by grounding the negative from battery to frame and the compressor kicks on then it's your AC switch circuit. Again, I think all of that is unlikely if you didn't replace anything else and have debris in the system.... All of those are suggestions on where to start looking. Good news is that you don't have a leak!!!! LOLOLOLOL

 

I changed mine out a month ago and that amount of oil seems a wee bit high.
If its a Denso,they come ready to install with correct amount of oil.
Always change out the dryer when installing a new compressor.
Your compressor could be slugging due to overfilling with oil.
Low (suction) side should be around 40 and High(pressure) side around 140.

 

So I replaced the drier and expansion valve. Now my I am getting readings on the low side 30-40 PSI fluctuating in that range and High side is at 175PSI. I guess condenser and evaporator are next. I might as well replace the evaporator if I'm doing the condenser. Makes no sense to have to go through it all again.

 

Also, I don't know if this has any effect on the AC but I removed the thermostat. I basically tore it apart but still need the thermostat shell for the plastic gasket. I've heard that sometimes it messes with the AC in some vehicles but I cannot see why it would effect this truck.

 

Expansion valve is under the dash behind the glove box in the evaporator housing. Are you sure that's what you replaced? Because now you talk about doing the evaporator when you do the condenser. If you were already in there for the expansion valve you pry should have done evaporator at that time or at least cleaned out the evap box. Now you're taking the glove box/evap box assembly out twice. There's also a thermister I believe it's called. A small thermometer on the evaporator itself that could be faulty for you. FSM provides ways to test it. Aside from all of that, the condenser IMHO is pry the most critical and or worn part of the system being on the front of the truck in front of the radiator. It takes a fair amount of road debris/ bugs/ dirt. That is where all of the heat exchange takes place. Jury is still out on the necessity of replacing the evaporator. I did it in my truck because that was the first time I'd ever done an AC repair and didn't have a lot of information to go by. That first time I replaced everything except the lines, so drier/accumulator, condenser, compressor, evaporator and expansion valve. The next few repairs I did, the one to my daily Honda Civic I just did the compressor only and my GF's Honda CIvic that I just did a couple of weeks ago I did compressor and drier/condenser as the Honda drier is already apart of the condenser. Her condenser was absolutely BEAT from road debris and whatnot. Didn't bother with evaporator or expansion valve. From my experience, what I noticed on the truck's evaporator under the dash was how dirty it had gotten. The whole housing is where your blower motor is for the fan and it sucks a ton of debris and dirt up in there... Rethinking and knowing more now, if I had to do it again on the truck I don't think I would have replaced the evaporator. It's a mini radiator/heat exchanger. I don't think they become damaged more than just dirty. Expansion valve controls the amount of freon being pumped to the evaporator so it doesn't freeze it up or worse, not get it cold enough. I've read these can clog if debris in system. It seems in general the rule of thumb is replace these components if you have had a compressor blow up and have metal debris in the system.

To clarify, are you saying that your low side is now coming down to 30-40 psi now with AC running? Are you getting cold air now or???

 

The problem is that you put Freon in an R134 system.

 

For the sake of keeping this simple, no.

 

Freon, R134... pretty synonymous. It's like calling every wound bandage a band aid. Band aid is a brand. I have written freon plenty of times in place of R134a. I'm assuming everyone already knows this.

 

the operating pressures are OK for your AC system, they will vary due to outside air temperature and charge level. As to your comment about the cooling system thermostat, it needs to be in the system for the cooling system to operate properly. The thermostats job is to keep heat in the engine. If you are experiencing inadequate AC temps and engine temps above normal there is a possibility that the AC condenser is partially plugged internally or externally by bugs and 15 years of road dirt. The AC condenser is basically another radiator in front of you engine cooling system radiator. If the fan clutch is worn or the shroud around the radiator/fan is missing, that too will effect both the AC system and the engine cooling system. Your center vent temp with the AC system on recirculate and medium fan speed should be around 40 to 45 degrees... some people get lower but there is the possibility of the evaporator freezing. One other thing that you can do is to take the fan out of the evaporator box and either feel with your hand the evaporator core or use a mirror and flashlight to see the core. Many many times leaves and other debris will clog the evaporator core causing poor AC performance and or smells (dead mice, mice nests, decomposing organic material etc).