AC Issues - 2007 Chrysler Pacifica

[DoubleWasp]

Now those pressures sound a lot more like it. The fact that you're stock fan with its factory program logic is able to correctly manage high side pressures is also a very good sign. Tends to look more like you have a healthy system that was simply overcharged than a system that is getting some way damaged.

It is correct that there was no way to evacuate the system of oil, other than to take apart the whole thing and flush out every component. Then add correct amount of the appropriate oil afterward.

 

[92saturnsl2]

Finally got around to getting the A/C evacuated and vacuum/refill the system. Applied a vacuum pump for 30 minutes, got down to 29-30 hg. Turned pump off, left it there for 30-45 minutes and seemed to hold vacuum fine. Refilled with the correct 1.5 lb. refrigerant, which conveniently is two full 12oz cans. For some reason the cans seemed to empty super slowly, perhaps this is normal but I spent a good while getting that last can into the system. When I removed the cans after they felt empty, each hissed for a few seconds, so maybe I lost some there. I also purged the yellow line before adding which wasted a bit, so might be an ounce or two low. Either way the thing is plenty cold now. Pressure while running is about 45-50 low side, and 200 PSI high side.

Ambient temp today was low 80's, high humidity so not brutally hot out and vent temperature is low to mid 40's drawing fresh air, and mid 30's when set to recirculate. So it looks to be the root of the problem was that the mechanic massively overfilled the system and perhaps didn't vacuum it out properly. Which reinforces why I don't take my vehicles to mechanics, but now I have the equipment to do my own AC repair, other than recovering the freon.

 

[DoubleWasp]

Good going. A little DIY went a long way.

 

[AC1DD]

Originally Posted by 92saturnsl2
So it looks to be the root of the problem was that the mechanic massively overfilled the system and perhaps didn't vacuum it out properly. Which reinforces why I don't take my vehicles to mechanics, but now I have the equipment to do my own AC repair, other than recovering the freon.



Indeed I would say at this point in the USA a DIYer with minimal skills that is good at following instructions on such work will end up doing a far better job then a
so called "professional" mechanic. Best part is you don't that "so called professional" through the nose to rip you off, make the situation worse, or break other items in their quest to scam you even more.

 

[bchannell]

Originally Posted by DoubleWasp
I agree. Needs a complete evac and refill.

What I see makes me think overcharged due to restriction.

What do I mean? A restriction will cause a high side pressure to be high, and low side pressure to below or negative. Someone notices low pressure on the side and thinks, " Needs more!".

By the time low side pressure makes any sense, high side pressure is just off the charts.

Last time I saw a vehicle do that, it was due to ridiculous over-oiling eliminating condenser efficiency. Condenser was so jammed with (Stop Leak?) oil that the condenser continued to discharge after removal. Sounded like Jiffy Pop.
Start with a proper charge to bring it back to Stage Zero, and then see what's going on.


Just to be clear, that statement makes logical sense, but in practicality, it is not true. If there's a restriction in the high side, the pressure goes down (I know, not intuitive). Remember a restriction means no, or low, refrigerant flow, no flow, now way for the compressor to compress anything. No, or very little heat is being moved from evap to condenser, which would also tend to lower the pressure.