Automotive Air Conditioning Information Forum (Archives)

Daren on Mon March 03, 2014 7:25 PM

Year: 2001
Make: VW
Model: Passat
Engine Size: 1.8t
Refrigerant Type: r134a
Ambient Temp: 64
Pressure Low: 30
Pressure High: 80

Just tried using the a/c yesterday and noticed that it is not blowing cold. I was thinking about using one of those DIY recharge in a can but decided against doing it. I was able to borrow a set of gauges from my neighbor to check and see what the pressures are. He was thinking that the compressor was no good and needs to be replaced because the high side is low. Is he guessing right? I prefer not to take it into a shop right away and pay them to tell me the same thing.

HECAT on Tue March 04, 2014 9:30 AM

Yes he is guessing, and I am glad you did not buy a DIY "death kit". Stay away from the cans that contain anything other than pure refrigerant. Pressures are used to measure performance. But without first verifying the accurate charge (by weight) is in there, pressures are unreliable and can be deceiving. If you are not tooled and experienced, a shop can perform a recover, vacuum, and recharge to validate or disprove your neighbors guess.



-------------------------

HECAT: www.hecatinc.com You support the Forum when you consider www.ackits.com for your a/c parts.

FLUSHING TECHNICAL PAPER vs2.pdf 

Cussboy on Tue March 04, 2014 1:12 PM

I've read that 60+% of refrigeration issues in vehicles are due to loss of refrigerant. So agree that you need to have the mount of R134a in your system measured, and if low: the leak repaired. If your system is low and you add pure refrigerant yourself, it's just guessing and that will also leak out.

It's not legal to add refrigerant to a known-leaking system except for the express purpose of pinpointing that leak, as I understand it.

Jag987 on Tue March 04, 2014 3:24 PM

Quote
Originally posted by: Cussboy



It's not legal to add refrigerant to a known-leaking system except for the express purpose of pinpointing that leak, as I understand it.

Cussboy, I would like to agree with you about not being legal to add refrigerant to a know leaking system but can't. This is true of mvac systems. From what I remember reading, with commercial systems, they can only be added to if in "x" amount of time they leak less than "y" percent of total refrigerant. But back to mvac, from the EPA site at http://www.epa.gov/ozone/title6/609/recharge.html, comes the following.


I wish it was not this way. But this is why the death kits and other recharge cans are legal. Evacuate, weigh, and go from there. If it has the correct charge, the refrigerant is not the issue. If the charge is low, the next step is to find out why, where is the leak? Good luck.

Jag

-------------------------
I bought a can of 134a at w**-mart that had a stop leak, oil, and dye in it. It also had a hose and a gauge, so now I'm an AC pro!

Daren on Tue March 04, 2014 7:43 PM

Thanks for the replies. Maybe I'll just take the car in to a shop that is capable of doing the work. I don't have the tooling to deal with a/c systems and don't want to start guessing and throwing money at parts.

Cussboy on Wed March 05, 2014 1:14 PM

Quote
Originally posted by: Daren
Thanks for the replies. Maybe I'll just take the car in to a shop that is capable of doing the work. I don't have the tooling to deal with a/c systems and don't want to start guessing and throwing money at parts.


Might be the best and most prudent approach. Equipment to do this job correctly (and still guessing how much refrigerant might be lost) would cost several hundred dolalrs minimum.


OK, see such FEDERAL regulations posted above, never claimed to be an attorney, a cop, or a certified refrigeration expert....

mk378 on Thu March 06, 2014 8:32 AM

It does look like it was just a leak-out, the compressor is pulling the low side down to 30 like it should but the high side only being 80 suggests there is just nothing in the system to pump. When a variable compressor is bad the high side and the low side will stay about the same no matter how much refrigerant there is.