Automotive Air Conditioning Information Forum

Hi forum friends,
New user and my first post. Thanks in advance for your help on this project...
93 Toyota Pickup 2WD 22RE engine. It was converted to R-134A maybe 10 years ago and has worked well ever since, until recently when the AC belt started squealing and smoking, so I pulled over and cut it off (glad it's a separate belt so I could keep driving!). I figured the compressor seized up since I could not turn the pulley, so I bought a new kit (Four Seasons, complete with a new receiver/dryer, TXV, and o-rings, and PAG 46 oil). I even bought a separate OEM TXV valve since I read a bunch of negative reviews about the Four Seasons TXV).
Turns out the compressor was not seized up!.. I could still turn the center part/clutch but the outer pulley was what locked up, I'm guessing it was a bearing? Anyway I'd already dismantled the system when I realized this, so just FYI.
I got an AC flush kit, manifold gauge set, and vacuum pump/oil from AutoZone (had to get special flush solvent from Napa Auto since AutoZone didn't have it). Got a couple 12 oz. cans of DuPont 134a on Amazon as well as some UV dye.
When dismantling, the old compressor SEEMED to have hardly any oil in it (darker, assume it was still original mineral oil?, FYI). All cleaned out nice and it sat for a few days so I think any solvent should have evaporated. New compressor, R/D, TXV and even a new OEM thermistor since the old one didn't show good ohm readings per the giant 2-book-size Toyota repair manual. I seriously believe I got the last thermistor ($9) in the COUNTRY! Anyway...
Per conversion specs 7 oz. PAG 46 oil and ready with 22 oz. of R134A...
I draw a good vacuum (1 hour) and it holds overnight so I'm happy and go to charge the system.
I took good notes because this was my SECOND attempt to charge the system. (before I replaced the TXV and thermistor, also cleaned the evaporator which was full of pine needles).
So here's what happens when I go to charge the system. (gauges= L: -29, H:0). Can attached, yellow hose primed/purged and ready.
I start the engine, turn on AC inside and blowers at second to highest force, and open low side on manifold gauge.
L-side jumps to 70 while H-side stays at 0.
After 10 minutes, clutch engages, L:55, H:50. Clutch remains engaged through steps below. There was no cycling on/off of the clutch.
After 20 minutes, L:57, H:70
After 30 minutes, L:72, H:90
After 40 minutes, L:75, H:100
After 50 minutes, L:76, H:115
After 60 minutes, L:76, H:115
I'm not sure how long an AC recharge is supposed to take but I figure it should be much faster than one hour?!
Note that during this one hour "recharge" the can is on a scale and apparently the system only took about 6 oz. of R134a in that entire time.
I shook can regularly and it felt cold.
So after the hour with head-scratching results I decided to call it quits.
With engine still running I close the LOW side on manifold (H has been closed the entire time), the low side drops instantly to L:0 (strange?), high still H:115
then when I shut off the engine, both low/high sides quickly stabilize at about 65
What the heck do I do now?
Thanks so much for your expertise and advice!
Michael

Other than the seized bearing, this situation doesn't make sense to me. Are you sure the manifold gauge set is working and that it's hooked up right? Did I understand correctly that this is a loaner gauge set?

Thanks for your note- Yes the TXV bulb is positioned just like the original, under the metal clip and wrapped in new insulation which was provided in the box by Denso, so that should be good.
I've been following recharge instruction videos from youtube, specifically ChrisFix channel, if that helps explain recharge process. Is there a method to recharge WITHOUT the compressor running? All the videos say to start the car and turn on the AC for the charge via manifold gauges. I'm not using a DIY can-attached-to-hose-with-single-gauge type of "can." Thanks.

Al9 wrote:Is the TXV's sensing bulb firmly attached to the evaporator's outlet? And properly insulated so that it's only sensing the evaporator's outlet temperature, too?

Ester oil is a great solvent so the dark oil you're referring to might well be Ester. Little oil found inside the compressor is normal occurrence when the system has been run with a low refrigerant charge. Clutch bearing might have failed due to prolonged clutch slippage as a result of this condition.

Charging by cans with the compressor running deprives it of lubricant.

Hey JohnHere, The gauge set is a loaner from AutoZone. I have no reason (?) to think it's not functioning correctly but I suppose that's a possibility. It's definitely "working" but "working properly" could be another thing. It's hooked up correctly per every (countless) videos I've watched, and it's idiot-proof in that L/H sides only connect to the appropriate fittings. Both fittings OPEN on the access ports/lines, and only L-side open on the gauge when attempting to recharge system. Even if manifold gauges were not working correclty, it seems the R134A should be drawn into the system faster than 6 oz. in one hour.
Also, I did check the air temp coming out of the vents and it was nowhere near cold (very warm), so it's definitely undercharged. Additional thoughts?

JohnHere wrote:Other than the seized bearing, this situation doesn't make sense to me. Are you sure the manifold gauge set is working and that it's hooked up right? Did I understand correctly that this is a loaner gauge set?

Hi Al9, Thanks for your input. System should be leak-free since I left it in vacuum for 24 hours and there was no changes to gauges (-29, 0), right?
I haven't seen any videos or heard of charging the HIGH side of the system, so that's new to me. I'm willing to try something new...
So, to be clear... I should RE-EVACUATE system and RE-VACCUUM?... Right now I still have the gauges hooked up with 6 oz. R143A in the system.
Just took a look and with the car off (couple days) and it's 109 degrees outside (yikes!), the gauges read: L:89, H:105 (not sure what that means just sharing).
If you have a suggestion (like charging on the H side), can you repeat with step-by-step words for a newbie like me? I'm scratching my head with terms like "oil charge loaded side." Is there a way to check for an obstruction (no issues blowing solvent or compressed air when I flushed it) or to test for a charge port/equipment issue? Is a "charge port" the access port(s) for L/H on the lines where you connect the manifold gauges to access the system? What could be the issue with a charge port? - or what would I do to check (or check off) any possible issues you suggest? Thanks.

Al9 wrote:Yes, do a deep vacuum (after making sure the system is leak free) and then charge by weight through the high side into that deep vacuum. Anything else than that, you're causing serious compressor wear. Professionals regularly carry the entire process without turning the AC compressor on, it's the only way to make all the oil promptly return to a compressor that has just been installed with the entire system oil charge loaded inside. If the system won't take all the refrigerant that way, there's either an obstruction within the system or a charge port/equipment issue.

Al9 wrote:I'm afraid MVAC isn't newbie-friendly stuff. I'd recommend you hand this over to a pro.

Vacuum is only one part of the leak test. The other is, you guess it, check how well it holds pressure. Again, this is pro stuff.

Everyone starts somewhere and I'm knee deep in this, plus I don't give up easily. I'll keep working at it with good info and helper's patience and clarity. Thanks for your time anyway, Al9.

I'm not sure, but Al must have meant charge through the LOW side. Attempting to charge through the high side is ill advised and downright dangerous, especially for a newbie. So keep that high-side (red) handwheel closed at all times while charging, and charge refrigerant only through the low side (blue handwheel, gauge, and hose).

Tim, our site administrator, has posted an excellent charging tutorial under "Automotive Air Conditioning Procedures, Tips and FAQ," first topic. Please read and understand that before proceeding.