[Vwdiesel] 2000 TDI a/c question - and a brief description of

Mon Jun 7 08:40:20 PDT 2010

Great stuff, thanks.  I will see if I can rent the guages from Autozone like I did with the 32mm socket for my wheel bearing job.
I can do this, I hope.

 Bryan Belman, Pt. Pleasant, NJ
04 Jetta Wagon TDI PD, 100hp, 5sp -- running :)
92 Jetta 1.6 Eco-Turbo Diesel -- running :}
82 Diesel Westy 1.9NA -- running :)
70 Type 1 stock Beetle -- Not running :( 

________________________________
From: Val Christian <val at mongo.mongobird.com>
To: Bryan Belman <dieselwesty at yahoo.com>; vwdiesel at vwfans.com
Sent: Mon, June 7, 2010 10:37:25 AM
Subject: Re: [Vwdiesel] 2000 TDI a/c question - and a brief description of

My comments:

Don't mess with adapting other guages...you can find a set for 134a for about $50.  Worth it, because over the next couple of years you will benefit more than that by having them.

Pressures are measured with the AC running, and it will cycle on and off.  You measure while the compressor is engaged, and have to do some human peak and average reading analysis.

As a general rule, I would get concerned if the high side gets over 240 and the low side over 35 or 40.  There are exact numbers, but they are dependent upon environmentals, and even then, there are wide tolerances.  A system can be a little less than ideal, and still work great.

Your 12oz can...has to evap (which will cool it) and the gas should go into the low side, while simultaneously monitoring the high side.  Intermittently stop feeding the gas in, and see where the low side is stabilizing.  Shoot for 20 to 30# max, if you can.

Higher ambients, mean higher pressures.

The acid test for emptying a freon can is the weight.  Everything else is an
assumption with less data.  But if the can is at ambient, and the valve
is open to the low side while the compressor is on, then the can is probably empty.

I had a friend, just before he got his PhD (education doesn't always help)
run his caravan over to show me how he recharged it.  He said he put 6 cans in.
He had over 600PSI on the high side, and couldn't understand the look of panic on my face.  He had kept adding freon until it stopped getting colder.  It's a wonder he didn't burst hoses driving the 10 miles to my house.

So get a set of guages...the ones with the red and blue knobs, and hoses.  You can still use a short hose for the low side, with a can of freon.  At some time you will buy a 30# 134a cylinder, and it will take care of your needs for a long time.  But get the guages.

Oh, the reason you don't put liquid, jsut gas, into the low side, is that you don't want to hydraulic lock the compressor.  

Also, on speed, you can do the entire job at idle, but I sometimes rev to 2500 to see where the pressures stabilize at, becase I figure that's where it will be running, when I'm going down the road (at least in the IDI).  I'm not an expert, but I've done this for 30 years.  And the guys who really know AC haven't laughed at me...at least to my face.  grin.

> 
> With all the great e-mails these past few days, I need to do something abou=
> t the=A0AC in my 92 Eco Jetta.=A0 I have a can of 134a and I know where to =
> put it in thanks to=A0Nick showing me when I stopped to see him on=A0our wa=
> y back up the=A0coast from FL.
> 
> But, to learn more about the system, I want to do the measurments of PSI on=
>  the high=A0side and low side before and after.
> I do not=A0think this gauge needed would be anything special for Automotive=
>  AC, so as long as I can get my diesel compression tester to properly conne=
> ct to the high side nipple, that should work, yes.
> 
> For the lost side, I can use my normal gas engine psi tester, the one I use=
>  for beetle motors and stuff.
> 
> My Questions.
> Do I take the PSI readings with the car cold or warmed up and running?
> 
> How much do I rev. the motor when putting in the 134a, about 2K
> 
> How will I know the can is empty, will there be condinsation on the outside=
>  to show or something like a propane bottle?
> 
> thanks
> 
> =A0Bryan Belman, Pt. Pleasant, NJ
> 04 Jetta Wagon TDI PD, 100hp, 5sp -- running :)
> 92 Jetta 1.6 Eco-Turbo Diesel -- running :}
> 82 Diesel Westy 1.9NA -- running :)
> 70 Type 1 stock Beetle -- Not running :( =
> 
> 
> 
> 
> 
> ________________________________
> From: Val Christian <val at mongo.mongobird.com>
> To: vwdiesel at vwfans.com
> Sent: Mon, June 7, 2010 9:33:43 AM
> Subject: Re: [Vwdiesel] 2000 TDI a/c question - and a brief description of
> 
> 
> Don't measure AC performance by how far people move away from you when you =
> arrive.
> 
> Put a thermometer in the air stream, on MAX AC, recirculating air.=A0 After=
>  things stabilize, the air coming out should be below 40F.=A0 On my 2003, i=
> t is usually 34F or 33F.=A0 =
> 
> 
> If it's 50F or 55F, and the outside air is less than 90F, you definitely ha=
> ve a performance problem.
> 
> If it's running 35F and you're just getting very little air, then you may h=
> ave a diverter not positioning itself, or a vacuum motor type problem.
> 
> Val
> 
> 
> 
> > =
> 
> > That's why VW Diesel owners are smarter:=A0 not only can they fix the =
> 
> > system, they can give great, well-written descriptions of the system.=A0 =
> 
> > As far as being better looking as well, that's just a point of fact.
> > =
> 
> > I appreciate the explanations from all.=A0 Combined with my rough =
> 
> > knowledge of the system and some half-remembered chemistry class =
> 
> > knowledge (I ran a supercritical fluid extractor in grad. school--forgot =
> 
> > about that), I think I have it.=A0 Took me a few days to assimilate it =
> 
> > all, though.
> > =
> 
> > I always do worry about the big, catastrophically expensive parts like =
> 
> > compressors in a car with 267,000 miles, but I'll hope for the best.=A0 =
> 
> > Hope is cheaper.
> > =
> 
> > What seems to happen is that the airflow through the vents is reduced.=A0 =
> 
> > I normally run the system on fan speeds 1-2.=A0 When the problem really =
> 
> > hit, I'd been driving almost an hour on recirculate and when I cranked =
> 
> > the fan to speed 4, all I got was a lot of noise and very little (but =
> 
> > cold) airflow.=A0 Turning off the recirculate helped.=A0 That was before =
> the =
> 
> > added can of 134a, and I've not had to drive a lot since.=A0 Tomorrow, =
> 
> > however, I'll have to make the same trip in even hotter weather.=A0 I'll =
> 
> > let y'all know.=A0 I'll also put on an extra layer of anti-perspirant, =
> 
> > just in case.
> > =
> 
> > =
> 
> > -Shalyn
> > =
> 
> > _______________________________________________
> > Vwdiesel mailing list
> > Vwdiesel at vwfans.com
> > http://www.audifans.com/mailman/listinfo/vwdiesel
> > =
> 
> 
> _______________________________________________
> Vwdiesel mailing list
> Vwdiesel at vwfans.com
> http://www.audifans.com/mailman/listinfo/vwdiesel
> _______________________________________________
> Vwdiesel mailing list
> Vwdiesel at vwfans.com
> http://www.audifans.com/mailman/listinfo/vwdiesel
> 