AC Diagnostic Help

If the freon is a little low, the comp will cycle on and off before the cab cools down. If the ambient temp is warm.
Leaks do indeed lose a little oil, but how do you know how much oil is lost? Guessing how much to add is not good. Too bad they don't have a dipstick like the old York/Tecumseh compressors. Those old systems also had more oil and ~5 pounds of R12. 21oz is a bit more of a critical charge.

 

Yeah... I am leaning towards that. To much or too little refrigerant might cause the issue I am having?

System did hold a vacuum and i am fairly sure no leaks... but i appreciate the heads up.

 

How about popping off the clutch plate on the AC compressor and removing a shim? I've done this a couple of times with the Subaru's I have and that seemed to kick off the compressor.

 

I really wasnt trying to guess oil level.

I drained new compressor, added 150cc per FSM, cycled by hand and then installed.

I guess my measuring the old compressor oil one understands how much oil is left in the system... thus preventing to much oil.

Would to much oil cause the issue I am having? How critical is the oil level?

 

150cc = 5oz. I don't remember the exact oil capacity for this system. The tag on my truck is MIA. What is the total system capacity, anyone?

 

Im in this same situation on a 2002 impala , the GM uses an Orifice tube, I was getting same readings as the ops. Turns out the compressor is toast so rock Auto for 80% new parts for 380$ You must flush your system!!!!

 

Haha, them days are over though

The compressor might be short cycling, cant remember if OP said he heard it doing that. Too much oil can keep good heat exhange from occurring at the condensor.. lots of variables in these situations where you're trying to DIY

 

Alldata says 5.1 fl oz

 

As far as oil level... all the compressors I remember doing said to drain the old one into a measuring device, and add the greater of 3oz or what you got out of the old one... never once do I recall getting more than the 3oz out of the old one.

As far as getting warm at idle, it seems to just be a thing with this truck and the mechanical fan. If a vehicle has a more sensitive fan clutch or a more overkill condenser, it can make it less prone to happening, and if you've got the charge low you can exacerbate the issue, but from what I've heard here, it is to some extent going to happen.

I put an electric Flexalite on mine (mostly for the MPGs), you could also add an electric fan in front of the compressor, there's plenty of room. Either way, more airflow when sitting so as to not heat soak the condenser is the key.

 

Yep, long gone.
Too much oil does that, and more. Extra oil displaces capacity for freon.

 

If the condenser wasn't replaced, which holds the filter drier, and the rest of the system wasn't flushed, there is too much oil in the system.

 

OP, I'm thinking you have way too much oil now in the system and here is why.

At the factory, all the other pieces of the A/C system are installed in place dry and the compressor is the last piece. No oil is placed in any of the other components except the compressor. A new compressor comes with that amount of oil (150cc) and that amount is intended to to be dispersed to the entire system.

The system is charged with R134A and engine is finally started and the compressor engaged. That oil in the new compressor then is circulated along with the refrigerant and some accumulates in the condenser, some in the evaporator, some in the hoses and misc. components and the remainder in the compressor.

IMHO the FSM is very confusing and could easily lead one to think that 150cc should be added whenever a new compressor is added. It is not. The best the FSM does is to give one an idea of how much new oil is added to the system when a single failed component is replaced. That is why you must think of balancing the oil in the compressor separate from adding more to one or more failed components.

 

I agree... from your suggestion and others.

My new plan is to replace the condensor as there is a good chance it might be clogged or damaged from previous compressor failure. At that time I will also clean out all the lines.

I think that should bring the 150cc oil level far closer to what the system needs.

But... I wont have time to deal with all that for a bit...

 

Reviving your post here. How did you find that the ground was bad? Was it just loose or something? I'm trying to run down the blinking light problem w/o taking to a shop if possible.

 

I could see that it was frayed

 

Thanks.

 

OP - were you able to fix the issue? I've got the blinking AC light on my 2013 and am wondering how to fix it.

 

Turned out my compressor was bad... all electrical controls and wires were OK.