OK A/C experts here's one.....

Nanotech Environmental · September 7, 2015

I've been having a problem with my AC system for a while now;

It holds a charge just fine, but it doesn't seem to keep oil in the system. Every few weeks, I have to recharge it with more oil and then it works fine for a while. When the oil level drops, the compressor goes into short cycle mode and won't stay running due to low oil.

The system doesn't seem to be losing its refrigerant charge because it maintains pressure in the normal range whenever I check.

If it's not leaking refrigerant, where is the oil going?

Can anyone give me some ideas, insight or input on what's going on here?

(Possibly related – the truck had a bunch of front end work done to it last year due to a deer strike. It needed a new condenser as part of that work.

I never had any problems with the AC before that, but it never works more than a few weeks now before I have to add more oil to it....)

Thanks in advance

Cheers,

Brian

anumber1 · September 7, 2015

Are you checking pressures with a gauge manifold or just with a low side can gauge?

If you are adding oil without opening the system, you must be using pressurized cans of oil, therefore, raising system pressure enough to not cycle the low pressure switch.

Where is the high side operating is the main question.

DaveH71 · September 7, 2015

How are you measuring refrigerant and oil levels and pressures?

You don't loose refrig system oil without loosing refrigerant. You do have a leak somewhere, you just haven't found it.

Take it to a competent mechanic, they need to vacuum it and maybe add some dye to find the leak.

Nanotech Environmental · September 7, 2015

Are you checking pressures with a gauge manifold or just with a low side can gauge?

If you are adding oil without opening the system, you must be using pressurized cans of oil, therefore, raising system pressure enough to not cycle the high side low pressure switch.

Where is the high side operating is the main question.

I've been using the pressurized cans. I use the guage that attaches to the cans. When I attach the gauge, it shows lots of pressure. IIRC there was roughly 60 psi in before I added a can of oil a month or so ago & the same the time before that. Haven't checked it now, but the AC stopped cooling yesterday in 32c heat.

How does one check the high side?

anumber1 · September 8, 2015

One would check the high side with a manifold gauge set designed for a/c sevice.

Seems you are just adding pressure (and probably way too much oil) to the low side.

I would hazard to guess you do indeed have a leak.

If you are going to do a repair, get a can of refrigerant with dye in it, fill the system, use a uv dectection light to find the leak. At this point you can use your refrigerant reclamation machine to empty the system.

After you have found and fixed the problem, its time to flush all the that excess oil from the system. Then you can then use your vacuum pump, evacuate the system, refill the system and check the pressures both high and low side to ensure proper system function.

A proper repair is going to involve specialized tools that are pricy as well as a solid working knowledge of a/c system theory as well as service information including the proper specs regarding system pressures.

Or, you can shoot a can of gas in it and hope for the best.

Edit:

Have the engine running and system operating when you shoot a can (with dye in it so you can find the leak) in it.

This way, the gauge on the can will be showing a more accurate reading of the low side. Static pressure does not mean much but operating pressures mean everything in a/c service.

Duke4AZ · September 8, 2015

Loosing oil/loosing refrigerant. Loosing anything, you have a leak.

Unless you are an A/C tech and qualified, which I am guessing by the question you are probably not. Not a lot of people are.

So here is the deal. You can put a can of die in to the system. I've done it to find leaks and fix the system. However, if you find a leak you are going to have to take it to a technician to get it repaired. That is unless it is just a loose fitting . . . you might check the torque on all interface locations to make sure all are sealed well. Again, however, if you have a leak you are going to have to take it to a technician to get the system at the very least evacuated. To break open a system, either legally, and if not a legal issue, at least environmentally responsibile, you are going to want to collect the waste freon/working fluid. To do that special equipment is necessary. As somone mentioned, expensive, functions specific equipment which, unless you are an AC tech, you probably don't have in your garage. So, if you find a leak, chances are you are going to want to take it to a "trusted" technician.

On the other hand, if you don't find a leak, you are still going to have the problem with no idea how to approach the problem. In that case, you are going to want to take it to a "trusted, qualified' technician to figure out what is going wrong and how to get it fixed.

Starting to get the flavor of this respose. A/C systems are not complicated, but there are a number of issues that can affect the system performance and reliability. Screwing around with it and not knowing what to look for, look at or even how to interpret the information you do collect can cost a lot of money. I am not a pro auto mechanic or AC pro, but when dealing with stuff like this, I take it only so far as to make sure I don't get into trouble or damage anything.

Best scenario is you know someone that does this kind of work, but if not, find someone you feel comfortable enough with relative to their knowledge, skill level, experience, equipment and $rates so that you feel like you did the right thing. If you know someone locally that can recommend a shop that is a plus as well. Who knows, maybe someone on this site is in your area and can either do or recommend someone.

Bottom line, if you don't know what you are doing and are not ready to invest the time and resourses to learn and be competant in what you are doing, won't waist time, money and anxiety trying to figure it out yourself. especially if it is your daily driver. (if a hobby car, play all you want)

An AC system is serious stuff where I live so I don't mess around with it myself if I feel it is the least bit over my head.

A long winded way to say, "take it to a pro."