First AC Job

[GrandPaTom]

After two failed attempts with canister recharges to my 2009 Escape, I decided to do it the right way. I did a dye test and found a failed condenser. Since I have gauges I bought a vacuum pump and proceeded to check out the whole system. I replaced the condenser, receiver/dryer, and all seals & o-rings under the hood. Also emptied oil from compressor & added 4 onces of Pag 46. Never had a problem with the entire system before this summer. Pulled vacuum for half hour & it held perfectly for several hours. Attached canister to yellow line, purged it, started engine with AC engaged and started the recharge procedure. Low pressure climbed to about 120psi, high only reached 60, and compressor did not engage. I think I followed all the procedures I learned from numerous YouTube videos. Any suggestions of what to do next to find the problem?

[tbirdtbird]

" Low pressure climbed to about 120psi, high only reached 60"
The low can never be greater than the hi.

1. Make/model/year?
2. Should vacuum at least an hour. Vacuum pump run by electric motor?
3. info we need is hi, lo, vent temp, RPM 1500-1800, recirc, doors open, max fan , max cool . ie a full load test

" found a failed condenser."
What does this mean?? Failed as in a leak? Or as in clogged up?

[GrandPaTom]

The vehicle is a 2009 Ford Escape 3.0 liter. It is an electric vacuum pump and on one attempt I did vacuum a couple hours.

Recirculation doors were open, fan & cooling set to max. Condenser had a major leak so lost some compressor oil. Have tripped compressor clutch at relay so it is capable of running if clutch engages. Looking next at replacing low pressure sensor and expansion valve. Can a low pressure sensor be tested with air pressure? Any tips on where high pressure sensor is on this vehicle?

I tend to think it's an electrical problem because it worked too well for several years before this failure. TD

[GM Tech]

May have an a/c code set---unhook battery for 10 sec and see what happens

[GrandPaTom]

Too late to try the Code fix. Should have done that yesterday but I drained the system last night in preparation for replacing Expansion Valve & Low Pressure sensor today. Found what seems like excessive oil all through the Expansion Valve. When I replaced the condenser (original issue) it was suggested that I drain the compressor and add new PAG 46. I only got about 1 1/2 ozs of old oil out & the sticker under the hood said system calls for 5 ozs. I figured that there was still some oil in various components & none in the new condenser, I opted for adding 4 ozs. Seems like a complete guess is all anyone could give me? I'm thinking that 4 ozs could have been too much & maybe that's why the compressor wouldn't engage? AC school is teaching me why old retired mechanics shouldn't try to learn new high tech tricks! TD

[tbirdtbird]

There has been no indication of how much 134 you installed into system, or how it was done. Weighed in? Guesstimate? What does the underhood sticker call for? Did you charge vapor into the low side?
Your pressures cannot be as you describe. The low can never be higher than the hi. Are your hose couplers making a good connection to the access ports? The cheaper hose sets don't always make good connections, giving erroneous readings.
Once you are done changing the low side sensor, this is gonna require a super good vacuum (more than 1 hr), a precise charge, and pressures taken in the way previously described.
Has system ever had sealer added? Are you sure there are no blown fuses or faulty relays? Usually you can swap relays around just for testing purposes.
AC is a technical field unto itself. It bears little resemblance to ordinary mechanical work.

As far as oil, unless you flush everything back to bare metal, and start over with oil, you (and we) can only guess how much oil is in there.

If comp never ran, then do not see how you could have gotten the full charge in. In all likelihood it is prolly undercharged right now which is why the LPCO is not allowing the comp to engage

You seem to be galloping down the street without waiting for us to give input.....

[GrandPaTom]

I was only able to post on the forum as of yesterday so much of my "galloping" was trial & error prior to that with some coaching from some YouTubers who seemed pretty knowledgable. I'll try to answer your questions.

I only got about 8 oz of 134 in the evacuated system before my gauges started climbing way high. I was charging through the Blue low side (red side shut down tight) using the yellow hose of my new, pretty good quality gauge set. Under-hood sticker calls for 21 oz of 134. To my knowledge there has never been any sealer in the system. No fuses are blown and I did swap out relays to check the comp-clutch relay, jumpered it at the socket and heard the clutch click closed.

Today I replaced the Expansion Valve, drained about 3 oz of oil from the compressor & put 3 oz back in. I then pulled a vacuum for about an hour & forty mins. It seems to be holding and in the morning I will attempt to charge again. I had pretty much concluded that the oil question is an educated guess. TD

[JohnHere]

A belated Welcome to the Forum.

Mrs. JohnHere and I took some R&R at a cabin in the mountains of North Carolina, so I've been off the Forum for a while.

Reading your first post, it seemed to me that the system just lost all its refrigerant due to the condenser leak. Thus, the PCM wasn't receiving the correct pressure signals to turn-on the compressor.

That said, my recommendation would have been as follows: Replace the condenser and R/D with the new components, leave the compressor alone, and add 1-1/2 ounces of oil to the new condenser and 1/2-ounce to the new R/D. Then, install the new parts, evacuate for a couple of hours, and re-charge into a well-held vacuum to specs.

However, you've gotten much more deeply into the system with the TXV and pressure-switch replacements, so you have no choice but to see the more extensive job through.

The pressures are puzzling to say the least, so check-out your Manifold Gauge Set condition and connections as previously suggested.

Like you, we can only guess at the amount of oil currently in the system unless you backtrack and start again with a completely "dry" system.

[GrandPaTom]

Thanks John. Now that all has been said and done, it sounds like I have done pretty much what you suggest. I did replace the expansion valve but not the low pressure switch. I then did a thorough vacuum test which held for 15 hrs and then succeeded in charging the system and seeing appropriate pressure readings & having the compressor engage. That was Friday & today I still have AC. The oil question sounds like an informed "crap shoot" but from your suggestions, I believe (hope) I'm in the ballpark. Thanks again. TD

[JohnHere]

That sounds great. Did you have an opportunity to measure the center-vent temps, and at what ambient temperature?

Sounds like you're pretty close on the oil amount, if a little over. Better that than too little, I think.