02 AC issue (1 Viewer)

[erwall]

Hey guys, ac has been working well until a recent trip. Compressor seems to be coming on as it should but air is barely cool coming out of the vents. Also noticed some dripping (very little but haven't noticed before) on pass side floormat just when it stopped working well. I was thinking maybe expansion valve is bad and is causing some freezing and is dripping into vehicle? Or is it more likely that I have a small leak somewhere and am losing enough refrigerant that it's not cooling well but not enough to make the compressor not kick on? Car has ~115k on it. I was planning on putting manifold/gauges on when I get home to check pressure. Anything jump out at you as far as possible issues? Thanks for any and all help.

 

[erwall]

Should I try replacing the expansion valve?

 

[nissanh]

Should I try replacing the expansion valve?

At 115k miles, I highly doubt you have a fault in the expansion valve.

Try this:
Check whether you have a AC filter (have to remove the glove box and there should be a plastic vertical door that you can lift off. If you don't have a filter, then you got lots of debris (dead leafs etc got trapped in the AC drain outlet and flooding the evaporator.

Try cleaning the drain first. You can lower the blower fan and carefully slide a vaccume clearner hose and pull the dirt off. Insert a small hose through the drain hose from bottom up and clean the drain tube.

Did you clean the AC condernser located in front of the radiator? Are the fins bent/clogged with bugs etc., Clean it. apply pressurised air or water (VERTICAL to the fins: Otherwise the FINs will BEND)

 

[erwall]

At 115k miles, I highly doubt you have a fault in the expansion valve.

Try this:
Check whether you have a AC filter (have to remove the glove box and there should be a plastic vertical door that you can lift off. If you don't have a filter, then you got lots of debris (dead leafs etc got trapped in the AC drain outlet and flooding the evaporator.

Try cleaning the drain first. You can lower the blower fan and carefully slide a vaccume clearner hose and pull the dirt off. Insert a small hose through the drain hose from bottom up and clean the drain tube.

Did you clean the AC condernser located in front of the radiator? Are the fins bent/clogged with bugs etc., Clean it. apply pressurised air or water (VERTICAL to the fins: Otherwise the FINs will BEND)

I'll try these things in a few days when I return home, thanks for the suggestions, I'll report back.

 

[erwall]

Checked the filters, they are present and had very minimal debris in them. Evap is very clean and free of debris. I ordered new filters and used lowish pressure air to clean existing ones and reinstalled. Dropped the blower motor and no debris present.

I evacuated the refrigerant and let the pump sit on it a bit. Turned it off and after about an hour there was no movement, so presumably no leaks. I started adding refrigerant and realized the compressor isn't turning off. It turns on/off with the AC button but never cycles once on. This resulted in ~300psig high side pressure so I stopped. This is surely why the air temperature is not very cool? Is this a pressure switch issue? Or a compressor issue? If compressor I would think it wouldn't turn on/off with AC button.

 

[ramangain]

What is the low side pressure right now?

 

[erwall]

Checked the filters, they are present and had very minimal debris in them. Evap is very clean and free of debris. I ordered new filters and used lowish pressure air to clean existing ones and reinstalled. Dropped the blower motor and no debris present.

I evacuated the refrigerant and let the pump sit on it a bit. Turned it off and after about an hour there was no movement, so presumably no leaks. I started adding refrigerant and realized the compressor isn't turning off. It turns on/off with the AC button but never cycles once on. This resulted in ~300psig high side pressure so I stopped. Is this a pressure switch issue? Or a compressor issue? If compressor I would think it wouldn't turn on/off with AC butto

What is the low side pressure right now?

22

 

[ramangain]

22 on the cold side should be enough to start getting colder air with AC on. Does it or not? Shoot for a minimum of 25.

 

[erwall]

Put some in to make it 25, still high on high side but it is cooling. Not cooling like I think it should be but sufficient enough for now.

 

[ramangain]

Put some in to make it 25, still high on high side but it is cooling. Not cooling like I think it should be but sufficient enough for now.

I'd beg if you get the low side to 35 psi, things will be good. You just went through what I went through last summer, except I cheated and just used a can of AC Pro.

 

[nissanh]

Did you check the sight glass located on the high side AC tube right below the driver side headlight? The slight glass should be clear (freon is flowing under the glass). Occasional bubble or two per second is OK, but not too much bubbling like fizzing soda. Add freon to clear the glass. Keep the AC on and blower full with doors open (so compressor is pulling freon in ). Make sure you don't invert the freon can up side down so it won't send liquid into the compressor).

Did you evacuate freon and air from both low and high sides? and charging freon only to the low side?

 

[erwall]

Did you check the sight glass located on the high side AC tube right below the driver side headlight? The slight glass should be clear (freon is flowing under the glass). Occasional bubble or two per second is OK, but not too much bubbling like fizzing soda. Add freon to clear the glass. Keep the AC on and blower full with doors open (so compressor is pulling freon in ). Make sure you don't invert the freon can up side down so it won't send liquid into the compressor).

Did you evacuate freon and air from both low and high sides? and charging freon only to the low side?

I'll check out the sight glass. Evacuated from low and high sides. Added as much as I could to high side before starting vehicle and added to low side after starting.

 

[erwall]

I'll check out the sight glass. Evacuated from low and high sides. Added as much as I could to high side before starting vehicle and added to low side after starting.

I got about 35 in low side and is working well but high side is WAY high, like 350. Possible condensor issue?

 

[nissanh]

Check out Scanner Danner Videos. According to his video below, you can see low side goes into a 0 psi or even vacuum upon compressor engagement. Also he said high side went to 300 PSi and he said that is too much.

Here is a AC disgnosis (sticking expansion valve) done by Scanner Danner. He got ton of good videos.

 

[TunaMelt]

You've got a restriction in your line somewhere. Don't add more refrigerant. Get a tech to evacuate the system, replace the condenser dryer filter (cheap), clean out the expansion valve, and try again. Sometimes the expansion valves have screens on them that you can clean out and reuse the same valve. If it were me going that far to use a shop I'd go ahead and replace the expansion valve. If you'd like to know for sure then take temps on your suction and discharge lines near the pressure taps and post those along with the pressures.

 

[erwall]

I just ordered a new compressor, condensor, evaporator, and expansion valve. Just going to do the whole thing and stop messing with it! I'll report back, thanks all.

 

[nissanh]

Get oem O rings if available. If not properly fixed all back together, once open AC system is a never ending project.

 

[erwall]

Get oem O rings if available. If not properly fixed all back together, once open AC system is a never ending project.

Had to use some generic ones that I've used in the past without issue, hopefully hold up. All the ones I just replaced are easily accessible if not.

 

[erwall]

Replaced the condenser and compressor last night. One of those was definitely the issue, as charging it wasn't a issue this time. 73 here and getting 40 out of the vents, we'll see how it does on a warmer day.

 

[vipergrhd]

I got about 35 in low side and is working well but high side is WAY high, like 350. Possible condensor issue?

Did your rpm go up with a/c on and does the fan clutch partially lock up to pull some air through the condenser? You also may have a dirty condenser that would require a good cleaning, clean the fins in the front and blow air or water through it.