AC help please! So hot. I need proper pressures.

[bben76]

I'm all in - I'm doing this!

I'm going to continue to document my project here for the sake of the community and my own self learning, continued assistance highly welcomed

So... after calling around today with no luck to try to find a shop that can do a flush without taking the system apart I decided the money I'd pay someone I'll just use to buy the tools and supplies for myself. At this point I'm $500 in so why quit :drink:, about $110 of that is due to my own lack of experience - if I had read a little more I could have avoided it. Oh well...

My next step is... I stumbled on this self-flush solvent at the auto parts store so I'm going to give it a try.


I bought a new receiver/drier and going to put that in, though I'm wondering if that's necessary ...but I wanted to error on the side of better than not to.

Then I'm going to buy either the harbor freight cheap vacuum, http://www.harborfreight.com/air-vac...ors-96677.html, or just splurge and get the more powerful but economical ($100) 2.5cfm pump, http://www.harborfreight.com/25-cfm-...ump-98076.html. And possibly the gauges, http://www.harborfreight.com/a-c-man...set-92649.html. I'm leaning towards trying the cheap route first, just buying the cheap vacuum and charging with the cheap lb gauge that comes with the 134a cans.

[Ryann]

Nasty. Do an R-11 flush.

[bben76]

evac'd, no luck :(

well fellas i got it evac'd and properly charged with no luck. still only chills to about 62-64 at the vent. it held vaccuum fine. the only clue i have to go on is the receiver/drier sight glass is frothy, the mechanic told me that possibly there was old oil in the system that might be reacting with the new and i should take all my lines off and clean everything out and put in a new receiver/drier and try again. here's a video of the froth in the sight glass.



any suggestions appreciated. i'm dying in this heat

[Ryann]

No. Evacuation does not remove any oil.

It will however remove any moisture that's IN the oil because as the pressure in your system drops so does water's boiling point, thus evaporating the water into vapor to be pumped out through the exhaust port on your vacuum pump.

[bben76]

yes, 62 deg. temp coming out of the vents.

when i get it evac'd will it pull all the oil out also? just wanna make sure i've got the right amount of oil in there.

[mistertonylee]

I'm assuming 62 deg. is the temp of the air coming out of the vents. If so, you've got to evacuate the system properly. Worked wonders for mine. If that's how cold the interior of the car gets, then you probably won't do much better.

[bben76]

how are you not happy with 62 degrees?

Because I live in TN!

[Kershaw]

how are you not happy with 62 degrees?

[Ryann]

The prescribed charge by weight for 134a was recently posted by another r3vster as being just under 32 oz.

PAG is the proper oil for a 134a system. If you added 4 oz. and the compressor came prefilled then you've got plenty in there.

Higher head pressure is harder on compressor internals. Also, moisture in the system from atmospheric air will cause the oil to become acidic and chew on your compressor and txv.

[bben76]

One last ques, will it hurt to run it with high head pressure?

[bben76]

Thanks Ryann and mistertonylee!

I've got a buddy with a shop so I'll have him pull a vac and recharge. I couldn't access the Google doc someone posted with amount to charge. Can someone tell me the formula or how much oil and 134a should be put in? And does it matter if it's pag or ester?

I thought about buying the harbor frieght tools but i read that the cheaper vaccuum tool wouldn't pull a really good vaccuum.

[mistertonylee]

Great! Thanks a lot.

bben, I bought the manifold gauges and a vac (runs by air compressor) at Harbor Freight for $65 or so. They were hugely helpful in charging the system and in giving the folks here some proper numbers for diagnosing. Hope you get your problem fixed.

[Ryann]

^Evacuation is not optional if you'd like a properly functioning system. If you had a discharge gauge you'd see excessive head pressure do to the presence of non-condensables (atmosphere).

Your compressor isn't cycling because your evaporator isn't getting cold enough to open the evaporator temperature switch.

OP: those pressures look pretty good!

[bben76]

Hi fellas. Don't mean to thread-jack but y'all seem to be a/c experts and so hoping you can give me a little insight also.

Here's the situation: replaced most hoses, new expansion valve, new receiver/dryer, used condenser and all new seals. Had the system evac'd, fired it up only to discover my compressor was locked up. So bought a freshly rebuilt compressor and installed, did not have system evac'd - so system was exposed to ambient air for only about the time it took to pull old comp and put rebuilt on. The rebuilt compressor came filled with oil, I don't know how much. So I added what I estimate to be 3-4 oz of oil charge and then started up and charged system with 134a using the cheap gauge that came with the can. I stopped charging when the gauge read about 40psi and was in the green - ambient temp was 80f. I ran 'er down the road for a test and held her at 2000rpm's, the coolest it got was only about 62f.

The sight glass looks to be foamy, the compressor never clicked off, the low side hose from the evap is cold and covered in water, and the fan is running but not sure at what speed. I feel like all the components are working correctly just don't think I got the charge right. Maybe too much oil? Should I have it evacuated and try again?

[mistertonylee]

So, good news. I was driving it tonight, and the ac cycled on/off. I'll admit, I was probably more excited than I should have been. I guess the refrigerant had to settle in the system or something. I don't know, but it was 90 degrees today, and I wasn't hot once. So, once again, thanks to everyone for all of their help on this issue.