Automotive Air Conditioning Information Forum

This all started after I hit a racoon that bent in my condenser. A few weeks later my AC started blowing luke warm so I bought a can of AC pro thinking the condenser was slowly leaking. The can gauge showed 40 PSI which was the middle of the green so it should have been good. I went ahead and added some charge to reach the upper area of the green. The outlet temperature never increased, then the clutch started cylcling on/off which I assumed was because I had over charged the system.

Fast forward to today, I decided to overhaul the system due to mileage and replace the compressor along with the condenser/dryer assembly and also the expansion valve. I replaced the components and flushed the system (lines, evaporator core) with an AC system flush agent. I added 80ml PAG oil to the compressor, pulled a vacuum on the system and pressure tested with no loss after 1 hr, and filled 15.5oz of R134a.

The system would still only give a 10-15 F temperature drop.

AC clutch engages properly, the radiator fans are running, the blend door is moving, the blower fan is new....

I evacuated and recharged the system and was able to get about 25 F temperature drop. That lasted about a week and now it is back to only giving me a 10-12 F temperature drop.

Ambient Temp: 80 F
Humidity: 70
Outlet Air Temp: 63 F
Outlet Target: 50 F
Static Pressure @75F (Engine Cold): Low 77, HI 78 (Target 77)
Static Pressure @80F (After Running): 63 & 145
Low Side (Blue) PSI: 35
High Side (Red) PSI: 165
Target Low/High: @80~Low 21-38/Hi 160-210

What are your thoughts?

The pressures look good to me, I added the proper amount of charge, and it was working almost to the factory target temperatures for a while.

If it had a leak, I would expect the pressures to be out of range.

The only items not replaced are the lines and the evaporator core. The lines weren't damaged or kinked by the racoon.

Folks, another can of the blackdeath jumps off the parts store shelves and again and again onto the pages of this forum.
Do not, repeat, do not use that stuff, it will clog everything.

How did you arrive at that oil charge?
and you charge by weight, not pressures.
For the record static pressures do us no good.
We want hi and low at 1500 RPM, along with vent temp and ambient.
what kind of vaccum pump did you use, electric or that HF wonder the compressed air model, which is useless.
Also, the gauges that come with those cans are notoriously inaccurate

Time for others to chime in.....

How did you arrive at that oil charge? ...The sticker under the hood states that amount by weight

and you charge by weight, not pressures. ....By weight, from a tank and digital scale

For the record static pressures do us no good....i don't know if it's right, but the site below used that to indicate if there was air in the system. if i pulled a good vacuum, and haven't sprung a leak that isn't my problem.
https://ricksfreeautorepairadvice.com/d ... th-gauges/

We want hi and low at 1500 RPM, along with vent temp and ambient.....@1500 RPM F: Low - 30, Hi - 185, vent 52 F - ambient 85 F
>>>>So today, idling at that speed, it is reaching down to 52 F. I've driven the car on highways for 4 hours over the last three days and it wouldn't drop the outlet temp below 61 F and that's with similar temperature, 85 F being the highs.

what kind of vaccum pump did you use, electric or that HF wonder the compressed air model, which is useless. .....My brother is an HVAC guy...i used his not sure if its 1 or 2 stage or what.

Also, the gauges that come with those cans are notoriously inaccurate ....I didn't use those gauge beyond the initial attempt to charge the system. I purchased a set (Harbor Freight) that I'm currently using. When I was pulling the vacuum and charging, I borrowed another set of gauges to use because the pump had a different fitting vs mine. (residential fitting vs automotive r134a)

You did better than it seemed, but you still have sealer in your system to muck things up and you did not comment on that.
Some shops will turn you away if they know you used sealer because it will gum up their expensive equipment

I am gonna guess that your brother, being HVAC, has little mobile (MVAC) experience. They are two different worlds. Nice to be able to borrow equipment, tho

Mist your condenser with a garden hose and repeat all the readings and report back

I didn't pay attention that the AC pro had sealer in it....I saw the 'MAX SEAL' version and thought it was the one with sealer and the regular did not. That was a mistake. Doh! I guess that could have gummed up my evaporator core or lines? I flushed the core and the lines with a quart of ac solvent.

Before mist
@1500 RPM: Low - 40, Hi - 185, vent 54 F - ambient 86 F

After misting
@1500 RPM: Low - 20, Hi - 145, vent 46 F - ambient 85 F

Well, to be honest, sometimes it is hard to tell what has sealer and what doesn't, if you still have the can check the label, and report back, thx
I do a boatload of AC work but am not a pro like the 4 other guys on here. These guys know stuff no one else knows.
I am not sure what they would tell you , ie would they want the lines and evap changed out or not.

A low of 20° should give an evap temp of about 18° but the air moving over would not quite be that cold. But, colder than 46°
18° is obv too cold, the evap core will freeze to a solid block of ice

I think we need input from the rest of the crowd

I checked the can and did did list 'Leak Sealer' on it 'capabilities' list.

sorry did or did not wording is awry

charliekeller wrote: ↑Wed Jul 21, 2021 12:46 pm How did you arrive at that oil charge? ...The sticker under the hood states that amount by weight

There was some confusion about measurement of refrigeration oil a couple of days ago in another topic. Oil specs are in fluid ounces or milliliters, not ounces of weight. That said, my references for your car specify 5.5 fluid ounces (163 milliliters) of PAG-46. You mentioned earlier that you put in 80 milliliters of oil. Was that a typo?