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If the system has been open or empty for 24 hours total the receiver dryer has to be replaced. It has dessicant (that junk that comes in little packets and says do not eat) which absorbs the moisture and it becomes saturated so the receiver dryer must be replaced
Quoted From 03AP1:
Hey everyone,
So I just want to start out by saying I have successfully diagnosed and replaced an a/c condenser before.
I have a set of gages and a vacuum pump and know how to work them well enough. I am NOT a mechanic, but just a DIY guy like many of us here on the forums.I have a 2004 Civic and the a/c is not quite cold on really hot days. The refrigerant level seems to be correct as far as I can tell. I am thinking the previous owner has perhaps had the system open and did not vacuum it before putting refrigerant in it, thus perhaps there is moisture inside the system.
I plan on bringing it in to a shop to get evacuated, vacuum it myself, then perhaps replacing the receiver/drier, then refill.
Now my question is will vacuuming pull the moisture out of the receiver/drier?
If not will it be worth replacing it?
How exactly can I tell if it is bad?
Thanks, Tom
It’s bad if it has been in the system sucking up moisture and becoming saturated. Whenever the system is opened it MUST be replaced you can’t pull the moisture out of it with vacuum. You can’t recharge them with vacuum they MUST be replaced.
If you’re going to open the system I would advise a system cleaning and replacement of all the O rings and S valves (2 — hi and low side). If there was excessive moisture in the system acid has probably formed inside due to the moisture. After you have your system evacuated of refrigerant give it a good cleaning, install the new receiver drier, vacuum and check for leaks, add the proper refrigerant OIL for what your system needs (less the OIL left in the compressor) do not overfill. Then charge the system with the R134a
FYI if you just replace the receiver /drier you need to add the correct viscosity refrigerant OIL back into the system to replace what will be removed when you take out the old receiver drier. Check the pump manufacturer’s specs for the recommended viscosity of refrigerant OIL to use with that pump and check the vehicle manufacture’s specs as to how much refrigerant OIL is used in the system and how much is attributable to the receiver / drier and only add the amount attributable to the receiver / drier back into the system. It is important not to over or under fill on the refrigerant OIL. Also check the specs on how much refrigerant (R134a) the system needs and do not over or under fill. These are important to obtaining the best efficiency from your A/C system.
Quoted From johnbkobb:
It’s bad if it has been in the system sucking up moisture and becoming saturated. Whenever the system is opened it MUST be replaced you can’t pull the moisture out of it with vacuum. You can’t recharge them with vacuum they MUST be replaced.
If you’re going to open the system I would advise a system cleaning and replacement of all the O rings and S valves (2 — hi and low side). If there was excessive moisture in the system acid has probably formed inside due to the moisture. After you have your system evacuated of refrigerant give it a good cleaning, install the new receiver drier, vacuum and check for leaks, add the proper refrigerant OIL for what your system needs (less the OIL left in the compressor) do not overfill. Then charge the system with the R134a
FYI if you just replace the receiver /drier you need to add the correct viscosity refrigerant OIL back into the system to replace what will be removed when you take out the old receiver drier. Check the pump manufacturer’s specs for the recommended viscosity of refrigerant OIL to use with that pump and check the vehicle manufacture’s specs as to how much refrigerant OIL is used in the system and how much is attributable to the receiver / drier and only add the amount attributable to the receiver / drier back into the system. It is important not to over or under fill on the refrigerant OIL. Also check the specs on how much refrigerant (R134a) the system needs and do not over or under fill. These are important to obtaining the best efficiency from your A/C system.
Awesome! I was too lazy to type all this but you hit the nail on the head
While you’re in there it probably wouldn’t be a bad idea to throw in a little UV dye so if there’s a leak in the future it will be easier to find.
Also, small car A/C systems usually struggle when it’s super hot outside. My little Echo has good air, but really hot days tax it. My GMC truck on the other had will blow cold regardless.
Another thought, change your cabin air filter too. A dirty filter won’t help the system at all.
I would probably replace the receiver/drier depending on how many miles are on the vehicle.
Just make sure you use the correct PAG oil as needed. If the shop you are taking the vehicle to has a Robinair machine, i would just have them add the PAG oil, refrigerant and dye as needed.
But thats up to you though 🙂
Eric also made a video on A/C –
http://www.youtube.com/watch?v=95RdGLFIbL8
You will be probably familiar with the procedure anyhow but i thought id share it anyhow.
My cabin filters are clean.
Will consider putting dye.
I have to look up the oil amount for receiver is there actually a considerable amount inside there? Didn’t even know there was.
I have 130k ish and its only $60 so I might just do it.
I wonder if I can order the PAG oil from Honda.
Yea Eric is the one who made me think of doing the receiver drier.
I’m not sure if the receiver dryer will solve the cooling problem, it can’t hurt to replace it mind you and it is true that moisture in the system can cause problems but I don’t think that’s the problem. To properly diagnose it you would need a manifold gauge set and observe the pressures and compare them to a temperature chart to evaluate the systems performance, it could be as simple as a low charge that’s causing it not to cool effectively, it could be an expansion valve that’s not working properly, it could be the cooling fan isn’t working, it could be a small leak somewhere, it could be debris in front or behind the condenser, fact is it could be a LOT of things so I don’t recommend throwing parts at it but rather taking the time to diagnose it properly before you commit to buying parts.
Thanks everyone, thanks Eric.
Well I am not COMPLETELY guessing however I am NOT 100% sure moisture in the system is my problem.
To properly diagnose it you would need a manifold gauge set
I do have a set.and observe the pressures and compare them to a temperature chart to evaluate the systems performance
I had a bit of trouble with this perhaps I could post here with temperature during my test and high and low pressures and someone could help?it could be an expansion valve that’s not working properly
Would a bad expansion valve cause partial cooling or just no cooling what so ever?it could be the cooling fan isn’t working,
My cooling fan is working.it could be a small leak somewhere,
I don’t believe it is a leak, I owned the car 5+ years and it has not gotten worse.it could be debris in front or behind the condenser,
I was thinking about this as well, perhaps when I get a chance ill take a look.If you posted the pressure and temp I could try to help out. All vehicles are different, but something thats drastically high or low would be obvious. Let us know what you find
An easy way to check for a restriction is equalizing time. Run the engine for a while and then shut the AC off. It shoud take at most 60 seconds for both low and high side pressures to equalize. If it takes longer, you have a restriction
sorry, one last thing. It is possible that the dessicant material in the receiver dryer clogged the orifice tube (or txv, whichever it has) and could be causing a problem
Quoted From rice400:
An easy way to check for a restriction is equalizing time. Run the engine for a while and then shut the AC off. It shoud take at most 60 seconds for both low and high side pressures to equalize. If it takes longer, you have a restriction
Restriction could be a bad expansion valve?
Quoted From 03AP1:
Restriction could be a bad expansion valve?
ahhhh crap now that i think about it i dont think that would work, i think it only works with orifice tube style ac systems
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