AC Woes. few things checked, what next?

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
Yes, Dan's thread covers the AC system for that era car fairly complete, concise. Not just the fans.
 

MarsBar

Veteran Member
Joined
Apr 28, 2008
Location
San Jose, CA
TDI
B4V#2 "Flash", 2000 Jetta GL, B4V#1 "PaTuDI" (2008-2018 RIP)
Just for clarification, when you say "compressor doesn't kick on" you mean the fan in the cabin is blowing air/working, just no cold coming out when set to a/c, correct?
 

Zheking

Well-known member
Joined
Nov 7, 2017
Location
Conway, AR
TDI
02 Golf
Have you read DanG144's excellent AC troubleshooting thread yet? Like you were told to do in posts 7 & 8? Actually read it? Slowly & carefully?

Stop throwing parts at it and diagnose the system. It's not complicated and everything is pretty easy to physically reach.
Yes. I'm not "throwing parts at it" the system is diagnosed... There's a slow leak in the compressor, and pressures indicated the compressor was on it's way out.

I probably will recheck the fuses though, just in case.

Just for clarification, when you say "compressor doesn't kick on" you mean the fan in the cabin is blowing air/working, just no cold coming out when set to a/c, correct?
Correct, yes the clutch isn't engaging.
 

rrgrassi

Veteran Member
Joined
Jul 31, 2006
Location
Royse City, TX
TDI
'06 Jetta TDI 5 speed
Is there a way to jumper the clutch to see if it engages? Engine not running, just put 12 volts to the clutch coil.

Also if the compressor is on its way out, replace it, and you will need to flush the lines, evap and condensor, just to make sure no metal bits are circulating. Also, replace the dryer and expansion valve. As said, do not use the Chinacool stuff. I learned that the hard way.
 

scurvy

Good Ol' Boy
Joined
Feb 21, 2006
Location
Chicago IL USA
TDI
2006 Golf
Went to charge the AC system for this summer. Got 1 can in (340g).
Throwing parts at it. Didn't diagnose it.

started on can #2. got to a point where it wouldn't suck anymore in, compressor still didn't kick on to suck more in. Think the compressor is dead?
Throwing parts at it. Didn't diagnose it.

note, compressor worked at the end of last summer until refrigerant got too low for it to kick on via pressure sensor (I'm guessing that's why?)
Wasn't diagnosed, guessing.

any other suggestions to check before I just grab a compressor, dryer, and expansion valve?
Diagnose the problem; stop throwing parts at it!

yes I know there is an AC thread but it mainly talks about fans from what I saw.
You didn't read it. It covers the entire system comprehensively.

Print it out at work, take it home. READ IT.

also, trying to figure out if i need the sanden or Nissens? (or is that just brand preference?)
Covered in Dan's thread. Read it.

I've come to the conclusion AC just isn't meant for my life probably. maybe I should move to Alaska. Home AC was dead tonight when I got home from the office to start this project. and Xterra AC wants to blow hot after about 25 minutes of sitting still idling...
Maybe, I dunno, diagnose those as well? Let a professional fix them?

I'm not "throwing parts at it" the system is diagnosed... There's a slow leak in the compressor, and pressures indicated the compressor was on it's way out.
1. You are throwing parts at it.
2. Since we know you haven't read Dan's thread, is that what was indicated?

Is there a way to jumper the clutch to see if it engages?
Covered in the AC thread linked.


Good luck Zheking & rrgrassi.
 

Zheking

Well-known member
Joined
Nov 7, 2017
Location
Conway, AR
TDI
02 Golf
Throwing parts at it. Didn't diagnose it.

Throwing parts at it. Didn't diagnose it.

Wasn't diagnosed, guessing.

Diagnose the problem; stop throwing parts at it!

You didn't read it. It covers the entire system comprehensively.

Print it out at work, take it home. READ IT.

Covered in Dan's thread. Read it.

Maybe, I dunno, diagnose those as well? Let a professional fix them?

1. You are throwing parts at it.
2. Since we know you haven't read Dan's thread, is that what was indicated?

Covered in the AC thread linked.

Good luck Zheking & rrgrassi.
Do you consider gasoline a part too? It's required for the car to run. Is the air you put into a tire a part? I've had to refill at tire while looking for a leak a few times before. Refrigerant is required for the AC system to run, but I wouldn't really consider it a part.... if you want to, fine.

I did read the post and all the links. No where does it talk about sanden vs nissan. Surely you aren't talking about printing and reading the 101 page thread are you?

Was diagnosed. AC system didn't work. Was low on refrigerant. Filled with refrigerant. worked perfectly until it got low again or the compressor finally failed.

When low pressure is higher than high side pressure, that means the compressor is on it's way out. The post and links didn't address it this, this is just common knowledge that is out there regarding ac compressors, and also what the FSM states.

actually from the fist post of said linked thread "AC troubleshooting:Folks, a reminder. This thread is for solving electrical control problems in the Mk IV Air conditioning systems."

A failing /failed compressor is mechanical, not electrical. I suppose an electrical issue could've possibly arisen during the winter when I wasn't using AC, don't see how though. WOuld be an amazing coincidence.
 
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KLXD

Top Post Dawg
Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
Low side can't be higher than the high side. Gauge accuracy issue.

Pump not running requires systematic troubleshooting to determine if it's getting power or where the ELECTRICAL fault is. If it is the clutch itself not working it can be replaced.
 
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BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
Seems you just need to find the leak and fix it. If you're sure it's in the compressor, we're done!
 

Genesis

Top Post Dawg
Joined
Feb 26, 2003
Location
Sevier County TN
TDI
'03 Jetta Wagon
First things first -- if it's leaking you need to find the leak and fix it. If there's any sort of UV dye in there a blacklight will find it FAST. If not it's cheap and "clean" (won't trash the system) to add a bit, and again, voila.

If the compressor is leaking at the shaft seal there's no rational thing to do but replace it. If it's leaking in the condenser or evaporator, or IN a line then obviously that's only got one fix too. The other possibility is any of the O-ring connections, or the service valves (which DO leak when they get old -- if they don't disintegrate internally, which also happens!)

But if you had more than ~30psi or so in the system and compressor didn't come on you have either (1) an electrical problem with the clutch coil or wiring to it, (2) one of the inputs to the ECU that tells the compressor to come on is not valid (pressure sensor, temperature sensor under the cowl, etc.) Throwing gas at a system that doesn't engage is a waste of time, and throwing gas in a system that is leaking is silly at best.

The "megathread" on this has a quite-complete troubleshooting procedure to figure out why the compressor isn't engaging. But you still need to take care of the mechanical (leak) problem and I'd find that cause first, then find the electrical issue because if the compressor is leaking AND the clutch coil is open then you're replacing the compressor (which will have a new clutch coil on it) anyway. Note that replacing the compressor REQUIRES a flush of the rest of the system components (and a new dryer) because the new compressor will come with oil in it and if you don't (1) there is likely to be crap in the rest that will destroy the new compressor in short order and (2) you HAVE TO get the remainder of the oil out of the rest of system or it will be quite-severely over-oiled, never mind full of oil that has gunk in it.

Oh, and it's illegal to intentionally vent refrigerant, so you SHOULD have a shop evacuate it. It's legal to pull your own vacuum and fill the system once fixed, however, provided you have the tools to do so correctly. You CANNOT fill these systems by pressure; you MUST do it by weight as the RCV in the compressor makes it impossible to get an accurate charge determination by looking at the pressures.

Finally since you're apparently new to refrigeration systems I will reiterate a warning I regularly post -- NEVER work on any refrigeration system without both FULL eye coverage (e.g. full-coverage safety goggles) AND hand protection (heavy gloves that go materially up your arm.) IF a line or seal ruptures while you're working on it, and it happens often enough to be of material concern the liquid in the system will flash-freeze ANYTHING it comes in contact with. If that happens to be your eyeball you're screwed.
 

Zheking

Well-known member
Joined
Nov 7, 2017
Location
Conway, AR
TDI
02 Golf
First things first -- if it's leaking you need to find the leak and fix it. If there's any sort of UV dye in there a blacklight will find it FAST. If not it's cheap and "clean" (won't trash the system) to add a bit, and again, voila.

If the compressor is leaking at the shaft seal there's no rational thing to do but replace it. If it's leaking in the condenser or evaporator, or IN a line then obviously that's only got one fix too. The other possibility is any of the O-ring connections, or the service valves (which DO leak when they get old -- if they don't disintegrate internally, which also happens!)

But if you had more than ~30psi or so in the system and compressor didn't come on you have either (1) an electrical problem with the clutch coil or wiring to it, (2) one of the inputs to the ECU that tells the compressor to come on is not valid (pressure sensor, temperature sensor under the cowl, etc.) Throwing gas at a system that doesn't engage is a waste of time, and throwing gas in a system that is leaking is silly at best.

The "megathread" on this has a quite-complete troubleshooting procedure to figure out why the compressor isn't engaging. But you still need to take care of the mechanical (leak) problem and I'd find that cause first, then find the electrical issue because if the compressor is leaking AND the clutch coil is open then you're replacing the compressor (which will have a new clutch coil on it) anyway. Note that replacing the compressor REQUIRES a flush of the rest of the system components (and a new dryer) because the new compressor will come with oil in it and if you don't (1) there is likely to be crap in the rest that will destroy the new compressor in short order and (2) you HAVE TO get the remainder of the oil out of the rest of system or it will be quite-severely over-oiled, never mind full of oil that has gunk in it.

Oh, and it's illegal to intentionally vent refrigerant, so you SHOULD have a shop evacuate it. It's legal to pull your own vacuum and fill the system once fixed, however, provided you have the tools to do so correctly. You CANNOT fill these systems by pressure; you MUST do it by weight as the RCV in the compressor makes it impossible to get an accurate charge determination by looking at the pressures.

Finally since you're apparently new to refrigeration systems I will reiterate a warning I regularly post -- NEVER work on any refrigeration system without both FULL eye coverage (e.g. full-coverage safety goggles) AND hand protection (heavy gloves that go materially up your arm.) IF a line or seal ruptures while you're working on it, and it happens often enough to be of material concern the liquid in the system will flash-freeze ANYTHING it comes in contact with. If that happens to be your eyeball you're screwed.
I think I have a pretty good idea where I need to go and what route I'll take from here now. I know compressor has a leak, as I did put UV in it last summer when I charged it. From what I could see, I did not see any leaks on any of the lines up to dryer and as best as I could see without removing the front end, i didn't see any on the condenser. I'm sure I will have a better view of it once I get the skid off to pull the compressor. Thanks to you and the others for constructive responses.
 
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