AC charged, no cold air

Hey fellas,


Recently bought a 2006 Jetta TDI and one of the main issues it's having is an AC failure. Previous owner said he tried to fix it but failed. Figured it had a leak and knew how to go about troubleshooting, but upon further inspection it seems the guy charged the lines to about 70+PSI. I emptied it and filled it to 35PSI with new freon but am now lost as to how to continue troubleshooting. It seems the compressor, valves, and fans often go bad on this model. But aside from checking the fans I have no way of knowing weather its the compressor or valves that went bad. Any tips for a rookie mechanic would be great. Air blows, its not hot, but not cold.

Edit:New update,
Cooling fans aren’t spinning, there’s 10 volts on 2 pins and ground on the other 2 inputs
Compressor is spinning when the AC is on.
PSI doesn’t appear to change between turning the AC on from it being off. Stays at 45psi on the low pressure side. Don’t got a gauge for the high pressure.

What are your hi and low side gauge readings off and with compressor engagement? Don't throw parts until you identify the issue and gauges will help and are almost a.necesity to isolate the problem

Sent from my FRD-L14 using Tapatalk

So you should just have a pro redo the system with a guarentee. Trust me. It's a lot of work to do it.
If you want to DIY then the first step is a manifold gauge and a vacuum pump and a volt meter. Test all the parts to make sure they work properly, dump the system out, drain compressor, new oil purge lines with nitrogen and new filter dryer, orings valves, the works. Vacuum it down, pressure test with nitrogen, not the vacuum, weigh in your charge.

95% confidence that the system is garbage with contaminated charge or that the electrical system is not working properly.

This thread is good for troubleshooting AC issues (much more than just the fan business)
Check your radiator/condenser fan operation NOW

I'll agree with Mongler on the re-fill, you can do it yourself but it's not simple.

New update,
Cooling fans aren’t spinning, there’s 10 volts on 2 pins and ground on the other 2 inputs
Compressor is spinning when the AC is on.
PSI doesn’t appear to change between turning the AC on from it being off. Stays at 45psi on the low pressure side. Don’t got a gauge for the high pressure.

don't need the condenser fans to get ac so long as you're moving the air's going through the rad faster than the fans move it anyways

pressure not dropping despite the compressor spinning stinks of stuck swash plate in the compressor
these are a variable displacement compressor and get stuck at zero fairly often

you should probably fix the rad fans before you worry about the a/c, but if all of your driving is freeway and you aren't overheating... toss a junkyard compressor at it, gasoline compressor is the same, so should be easy to find at u-pull
then bring it to some shady shop to get it vacuumed and charged, or buy a used vacuum pump off craigslist, or make one from an old refrigerator compressor (though it won't draw enough of a vacuum to eliminate water without heatgunning the dryer)

*Or* low pressure cutoff not allowing the AC to start. 45psi is high to reasonable, when running, but unacceptably low not running.

At 85 degrees, you should see about 90psi on both high and low side. Running, and at a similar temp. around 230 on the high side, and 30 low.

You are grossly undercharged! And it was undercharged in all likelihood when you got it (you don't give the temp when yiu saw the initial pressure . . .) but a lot closer than you are now.

And you did pull a vacuum before recharging after you emptied it, right? If it has air in it, it will never cool properly . . .

So talking about PSI, I thought 45 PSI was optimal for low pressure with the AC off and like 10 with the AC on. Even if I was undercharged shouldnt I see a change in pressure once the ac kicks in?

Edit: when I first checked the pressure once i noticed the AC wasn’t working, it was sitting at 70PSI and still not blowing any cold air.

QuickTD said:

Compressor is always spinning on a 2006 jetta. The compressor is electronic displacement control and has no clutch. It just idles with the swashplate in neutral when not in use. Audi has been doing this since 2002, VW since the Mk5.

Click to expand...

****, I thought it was still a mk4 with the non-cycling clutch

I'm dumb

So I’ve seen a lot of posts saying 28oz is the weight added, but the official VW page says 525g(18oz) for the 2006 mk5? Also when I vacuum and I’m not swapping parts, do I need to add more oil for the compressor or will that just sit at the bottom and it’s not something I need to do? Greatly appreciate the feedback

Is there a sticker under the hood with the proper weight?

Negative, looks like it was removed

Correct amount is 525g +-25, so 1.1-1.2 pounds .
The thing is with 2006 clutch always working, there is a regulation valve that decide when to turn compression On/Off.


Where are you in TX?

Shigmada said:

So talking about PSI, I thought 45 PSI was optimal for low pressure with the AC off and like 10 with the AC on. Even if I was undercharged shouldnt I see a change in pressure once the ac kicks in?

Edit: when I first checked the pressure once i noticed the AC wasn’t working, it was sitting at 70PSI and still not blowing any cold air.

Click to expand...

Not in R134a! And as I noted prior, most systems protect by not running on low pressure (not sure on the variables displacement comps, since they spin all the time, thus the protection due to low charge/low lube isn't really a factor).



http://rechargeac.com/how-to/ac-system-pressure-chart


If the charge is too low, you can't get enough high side pressure to condense gas to liquid, and zero cooling can occur . . .



But, as others have noted, if you are not seeing any pressure change running, and your compressor has an RCV, then either the RCV or the compressor outright has died.

Shigmada said:

So I’ve seen a lot of posts saying 28oz is the weight added, but the official VW page says 525g(18oz) for the 2006 mk5? Also when I vacuum and I’m not swapping parts, do I need to add more oil for the compressor or will that just sit at the bottom and it’s not something I need to do? Greatly appreciate the feedback

Click to expand...

If the system has not had a catastrophic "blowout" causing the loss of oil, it should still be present internally. The key thing is to know the history . . .



If this *IS* a clutched compressor, and it is running (IE no RCV) then the compressor has died . . . Sometimes it's hard to tell. If it *is* clutched, pull the connector off the clutch (typically near the pulley) and see if it stops, and check voltages. If it isn't clutched, feel free to ignore this suggestion

Op states on 1st post vehicle is a 2006 jetta.
Variable displacement compressor stock on mk5 jetta

This is why i say You should NEVER re-charge Your own A/C Yourself on my 2012 tdi it was'nt blowing cold cold ...so i took it to my mechanic he hooked it up to his A/C machine wich then proceeded to evacuate any left over r134 & moisture from the system then he added dye & exactly what it called for on R134 and $75.00 later it works like a charm.

Bullpoop! I have redone systems ranging from a tad low to flat with a blown compressor that had to be changed, and every one ran 100% good as new, and for years. This isn't rocket science, but you do need to have the equipment (and no, that does *NOT* mean a derp proof automated system . . .)

johnsTDI said:

This is why i say You should NEVER re-charge Your own A/C Yourself on my 2012 tdi it was'nt blowing cold cold ...so i took it to my mechanic he hooked it up to his A/C machine wich then proceeded to evacuate any left over r134 & moisture from the system then he added dye & exactly what it called for on R134 and $75.00 later it works like a charm.

Click to expand...

This is interesting as our 2011 Jetta was not cooling enough and the service manager from VW told me to just add a bit of r134. I did the same to our 2014 Jetta. So as far as never goes.....hmmm.

80% of all ac issues are electrical. Only after you have exhausted all the electrical parts with a diagnostic device of PROPER application (happy now!) do you even need to think about the charge or pressures.

This thread is a complete Fail Train. If people do not understand the system in question on the OP's car (and clearly the OP does not understand either), then do not post. You are not helping.

The BRM engine in question uses a NON-CLUTCHED compressor. It is always "spinning".

The car has OBD for the Climate system. You needn't dork around with anything besides a scan tool at first. If you do not have a scan tool that works on this car, and can interface with the Climate, stop working on the car.

You can easily watch the refrigerant pressure sensor value in the Climate scan data, as well as compressor request (how much duty cycle the RCV is getting).

Chances are very good it is either a bad RCV, a bad pressure sensor, or the wiring to either.

The fans are controlled by a solid state control unit, that is integral with the left fan motor. Again, messing around without a scan tool is a waste of time, and you can damage things. Fan motors are common failure items on these. However, this car's fans will NOT be commanded on until the pressure sensor gets above a certain threshold. If the RCV is dead, the system will never, ever, generate enough pressure to warrant the fan controller be requested to turn the fans on low speed.