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Old 06-12-2012, 07:28 PM   #1
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Default AC woes

Got the 99 back on the road after sitting several months and the air conditioning took a ----.

Compressor kicks on in short bursts of a few seconds and it will blow cold air during that time.

Went to the same shop that recharged the system on my 94, and was told this:

Quote:
System low; has a leak at the compressor; evac and re-charge with correct amount of R134AL
Re-test: system has a blockage - suspect expansion valve - possibly need an expansion valve, a drier, and a compressor; also needs a condenser flush
I need to fix this on the lowest possible budget and need suggestions?

Is it feasible to have them evacuate and re-charge with me replacing all of the parts with used parts? Do I need to use new parts?

AC is magic to me, well above my head.
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Old 06-12-2012, 08:14 PM   #2
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new drier. i bought a 99-00 drier and expansion valve for like 50 iirc with shipping from rock auto.
good used compressor, blow all of the lines out with sc solvent then blast with nitrogen. replace all the o-rings you take off and lube them with compressor oil.
you are lucky, the 01-05 has the drier built into the condensor.... so my drier is sitting here while i debate whether i want to use it or not...
compressor, look around to see if anyone rebuilds them in your area, or try a used one, im a bit warey because all of the compressor failing threads on m.net...
in reality, the nb's ate expansion valves under warranty.

im in the process of probably doing the same thing to mine, ac is definatly wizardtry to me...
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Old 06-13-2012, 07:50 PM   #3
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Old 06-13-2012, 10:49 PM   #4
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http://blog.choppedoctopus.com/2011/...ing-my-ac.html

Looking promising.

Thinking about picking up a used compressor and sealed evaporator unit that hopefully has a good expansion valve, and a new drier.

Also considering cleaning my existing evaporator and putting a new expansion valve on it.

Anyone with a evaporator unit pulled they want to sell cheap?
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Old 06-14-2012, 02:13 PM   #5
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I wouldn't follow that shop's "work flow" given they returned a repaired car that isn't work. The compressor cycling on/off with a recent recharge, sounds like an overcharge and excessive pressure causing the high pressure switch to cut the compressor off. Compressors on - pressure rises - switch trips - compressor off - pressure drops - compressor on...

The proper thing to do is put a gauge on the system and verify a excessive high pressure. If you are a total hack and don't mind risking your **** (you and the AC) - you could verify the switch is indeed cutting off the compressor by wiring in a switch to jump those leads (keeping the switch in the circuit). As soon as the compressor cuts off, flip the switch and see if comes on and immediately turn it back off. At that point you would know that you either have high pressure or an erratic/bad switch (or even wiring).

fwiw - I picked up the HF AC gauges for something like $45 after coupon. No regrets there.
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Old 06-14-2012, 02:47 PM   #6
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Quote:
Originally Posted by m2cupcar View Post
fwiw - I picked up the HF AC gauges for something like $45 after coupon. No regrets there.
I just picked-one up for my GFs Jeep. Also, be ultra-sure to charge with R134 and NO SEALANT!!!

For now, pick up a can of R134 with dye, charge to 40psi, drive it, then look for the dye. If you have to work on it and air gets into the system, you'll need to vacuum and refil.
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Old 06-15-2012, 10:38 AM   #7
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Autozone used to rent the vacuum pump. Call them and see if they still do.
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Old 06-15-2012, 11:02 PM   #8
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The hf gauges sucked. No way the low side fitting would fit... returned and lost quite a bit of freon in the process...
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Old 06-16-2012, 08:57 AM   #9
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Quote:
Originally Posted by m2cupcar View Post
I wouldn't follow that shop's "work flow" given they returned a repaired car that isn't work. The compressor cycling on/off with a recent recharge, sounds like an overcharge and excessive pressure causing the high pressure switch to cut the compressor off. Compressors on - pressure rises - switch trips - compressor off - pressure drops - compressor on...

The proper thing to do is put a gauge on the system and verify a excessive high pressure.
iirc he was saying that pressure was bleeding too much into the low side. He also thought it is likely that material from the drier came loose and made its way up the system. Neither of those make sense to me. Wish I was filming the gauges when he was explaining it. Said the system is trying to save itself by turning off when it seeings the pressure differential is not right.

Will call around and see if anyone rents out equipment, so I can give you better facts.
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Old 06-16-2012, 09:58 AM   #10
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Quote:
Originally Posted by fwMiata View Post
The hf gauges sucked. No way the low side fitting would fit... returned and lost quite a bit of freon in the process...

I have some that are 4-5 years old and have been on 30-40 cars with the only issue being a cracked low side handle that now has vice grips on it.
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Old 06-17-2012, 12:22 AM   #11
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Maybe you were trying to fit the low on the high side?
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Old 06-17-2012, 10:10 AM   #12
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Or put r134 fittings on r12?

94mx5- sounds like BS to me. But of course w/o seeing the pressures- or actually being there, I'm speculating.
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Old 06-17-2012, 01:09 PM   #13
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Quote:
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Maybe you were trying to fit the low on the high side?
Ya.uh no... tried them on my miata, wife's range Rover and for good measure my moms discovery. All r134... all no fit...
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Old 06-23-2012, 06:43 PM   #14
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Old 06-23-2012, 06:48 PM   #15
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looks normal right?
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Old 06-23-2012, 07:03 PM   #16
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Here is static pressure with AC off:



Tough to see it in the picture, but the sludge has a greenish hue. Mechanic said that is a leaking spot. The refrigerant is a neon green- accidentily discharged a little on the valve cover when figuring out how to disconnect everything.

Attached Thumbnails
AC woes-1c0ad56c.jpg   AC woes-81d68d85.jpg  
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Old 06-23-2012, 07:08 PM   #17
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The oil is neon green. Iirc the refrigerant doesn't really have a color.
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Old 06-23-2012, 07:10 PM   #18
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I think the low side is supposed to hold low rather than rising. Mechanic said the low side rises and the compressor shuts down. Probably a sensor tells it to.

I have to read through everything I already forgot from my research this week. At a minimum, I know I am low on freon.
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Old 06-23-2012, 07:14 PM   #19
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Going to have to pick up a new low side feed tube too. Walked past the car a while after finishing, and I heard it leaking from the port. It's similar to a tire valve. Messed around with the little thing in the hole and stopped the leak.
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Old 06-24-2012, 12:17 PM   #20
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These are pretty good reference on how to take out the compressor and evaporator.



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