A/C help - system won't take more than 24 oz 134a....

[vagonan]

I recently did a 134a conversion on my '89 Carat
-replaced the orings, compressor, hoses, receiver drier, and the expansion valve.

I did not see any fragments/dirt in the lines so I skipped flushing.

I've added total of 8oz PAG oil after draining the ester oil out of the compressor.
Then vacuumed the lines to ~30" for more than an a hour.
When I go to charge the system, it won't accept more than 24 oz of 134a. According to the Bentley manual, it should accept 40-45 oz.
Pressure reads ~45-50 psi low side which may be too high.
But the air coming out of the vents don't feel icy at all. It feels slightly cool at freeway speeds on a warm afternoon.

I've tried the routine twice but no luck.

Can anybody tell what may be the issue?

Thanks

[tencentlife]

How are you installing the 134? You want to feed it gas only (don't flip the can upside down or it'll suck liquid), and with many systems, you can passively feed about half the gas in, then you have to coax the rest. If you dip the can in a bucket of hot water it will boil off the liquid and raise the pressure to help force the gas into the line. While you do that, rev the motor to increase the suction. If you do both of those things, you should see the gas disappear into the system pretty fast.

40-50 on the low side isn't odd at idle, especially if the system is warm and not moving down the road. It should drop into the 20-30 range when you rev it a bit. While you're filling and testing, it's good to put a shim of cardboard in the throttle gap to raise the engine speed to 1500-2000rpm. And without good airflow at the condensor, you'll see overall system pressures rise as the fluid heats up; it takes a lot of air movement to cool the condensor. If you spray water on the condensor you'll see both pressures lower and the vent temp will fall dramatically.

[Terry Kay]

How much pressure is on the high side?

Get the engine on high idle ( 1200---1400 RPM ) and stick a box fan in front of the lower grill to blow continously on the condensor.

It sounds like you have something jammed in a line--floating garbage, and may have settled into the capillary tube of the expansion valve.

That'll slow the system down right now.

You should have taken the time to back flush the system.
This would have eliminated the possibility of some snot plugging the high or low side lines up.

Oops.





_________________
T.K.

[vagonan]

Thanks for your advice guys.

At idle, low side reads 40 and hi side reads 200
~1500 rpm, low side reads 25 and hi side reads 200 too.

The reason why I passed on the flush was because I didn't see much contamination in the components, replaced all the hoses, exp valve, drier, and compressor. Bad idea.... should have flushed. Just didn't have access to compressed air.

I just remembered, during my previous experiences with other vehicles, the cans got emptied a lot faster and they all worked fine w/o flushing.

So what do you guys suggest I do now?
I also regret not converting to REDTEK.

Thanks.

[Terry Kay]

The high and low side pressure is right at high idle, and a little high on the low side at low idle.

If the evaporator isn't throwing any cold air , something is plugged.
The freon isn't circulating for some wild reason.

With the gauges still on the Van, and you shut the engine off with the AC still on, does the gauges still read pretty much the same pressure, or does it fall down to nothing?

You installed all new hoses, or just some of them ?
_________________
T.K.

[vagonan]

Thanks for following up Terry.

After shutting off, the low pressure goes up and the high pressure....not sure. I'll have to check again.

ALL hoses were replaced.

The evaporator does seem cool but not cold.
On a warm day 80F it does blow cold at freeway speeds, but after recirculating the air for ~30min. Very weak at idle.

According to Bentley, I should be able to put ~40oz in the system but it's more like 20oz, slowly too.
Too much oil?
What do you think is taking up space?

Is this the consequence of 134a conversion???

Would you suggest recharging with REDTEK?
or would I just need to flush/replace exp valve & drier again?

Thanks for your help.

[Terry Kay]

If you have replaced the dryer already you shuld be good to go.

It's the small orfice in the expansion valve that sounds like it has some blockation---

If it's holding pressure after you shut it down It sure sounds like the expansion valve to me.

You can clean it out with air dryer alcohol, and usually the snot will back blow outa there.


You can still do the Red Tek swap--No big deal.
But you'll have to make sure that the system is free of all flying & floating objects first.

You could have had some garbage in the evaporator core, and when you cranked up the pressure with the 134A it broke loose and jammed the expansion valve.

This is what it sounds like to me anyway.

How cold is cold on the roll?

Will the temp drop if the Van is not on the fly, and just with a box fan in front of the condensor?
_________________
T.K.

[vagonan]

Box fan didn't have much effect.
My van is an automatic, cruising at 7-75mph -rpm 4000-5000rpm. It blows mildly cold. Enough to keep me cool when the blower is in my face.

I'll try cleaning that expansion valve but I guess I'll have to flush out the evap and condensor too.
Do they really have to come off the vehicle before flushing??

[kayakwesty]

terry is leading you the way...a trick Dogpliot showed me on here...was that to get to the expansion valve it can be accessed thru the driver's side speaker

it helps to have stubby wrenches for this job, if you want to get to it

you'll love the red-tek stuff btw
_________________
1984 Westy 2.0 Jetta ABA Motor/1.8 head converted to auto tranny, with 180,000 on body, 55K on engine and transmission

B.5.5 Passat Wagen with 30v V6-67000 Miles

DAS AUTO

CHANGE YOUR FUEL LINES!

A post without pictures is useless

http://www.kayakwesty.com

http://www.waldensridgewhitewater.com/

[Terry Kay]

<<My van is an automatic, cruising at 7-75mph -rpm 4000-5000rpm. It blows mildly cold. Enough to keep me cool when the blower is in my face.>>

What's mildly cold?
40 degree's
Get a thermometer in the vents and let us know.


<<I'll try cleaning that expansion valve but I guess I'll have to flush out the evap and condensor too.
Do they really have to come off the vehicle before flushing??>>

No, No , No.

I posted the easy way to do this a month or so back.

Remove both the lines at the compressor.

Load up the low side with air dryer alcohol.
Blow it through till the snot comes out the high side hose.

Reverse this act filing up the high side, and blowing it back through the low side hose.

Jump back a foot.

A lot of crap will blow outa the hoses.
Bolt it all back up, and suck it down, and reload.

Here's another reason you may not be getting much cold air.

Did you remove and clean out the evaporator coils of all the black foam rubber garbage installed at the factory so some air gets sucked through it?

Washing out all of the dirt its been injesting for how many years will increase the air flow through the evaporator coils.
Plugged coils will slow down any cold air movement through it real quick
_________________
T.K.

[vagonan]

Thanks for the advice Terry.

I checked the temperature on the vents today, here's what I found.

6pm 90F outside
After a few minutes of city driving I got 70F.
At freeway speeds I got 63F.

Better than nothing but far from satisfactory.

Regarding the flush method you recommend:
So I would be flushing right thru the drier and expansion valve too?
I've been checking online for that air brakeline fluid but I can't find that at the local parts store. Any recommended brands/distributor?

Thanks a ton.

[Terry Kay]

Disconnect the lines at the compressor, and pour about a quart of the air dryer alcohol into the low side--blow it through the low side lines.
Reverse the proceedure through the high side lines.

The only way to get the garbage cleaned out of the system is leave everything connected.

Air dryer antifreeze is available at any truck stop, Mack, Peterbuilt, Kenworth, White / Volvo / GMC, Freightliner , Sterling, or IH Dealer, or any class 8 semi truck parts distributor in your area.

Write off the internet--pick up the yellow pages and let your finger's do the walking for a truck parts dealer in your area.

It's a very common air system item, and isn't expensive.
_________________
T.K.

[pete000]

Great thread, I have been tuned in from the start. I am going to be doing a system flush out and convert to the Red Tek soon. I will post my findings when I do.

Thanks guys
_________________
1990 Vanagon RS 2.1
1967 Deluxe 21 window
--------------------
Koni Shocks
H & R Red Springs
Addco Sway Bars Front-Rear
18 X 7.5 and 18 X 8 OEM Porsche Wheels
Recaro Power-Heated seats

[vagonan]

Thanks Terry!!
I'll try the whole thing during the next few weekends.
I will keep you updated.

[vannygun]

i converted to 134 about 2 years ago,my compressor sounds like a big block supercharger so i figured it would go to compressor heaven soon(high pitched whine LOUD)anyway i didnt expect it to be around for long so i didnt even flush it.i think it was bone dry when i bought the vehicle because the low pressure switch was open, no voltage at the compressor.i pretty much slapped it together with no plans for a long term life.i get about 51 degrees f at the coil and it only took about 25oz when i brought it back to life.over the winter i lost about 12 oz,1 can later im back to cold air.people look at me funny when im at a red light.my muffler is shot and i have an irregular lumpy idle combined with the compressor whine sounds like im ready to run the 1/4 mile in under 9 sec.then on the green light im off like a geo
_________________
definition-Vanagon, "a ideal breeding ground for gremlins"
2000 jeep Cherokee sport (DD)
1990 vanagon gl 2.2 subaru(sold)
2006 jeep commander

[vagonan]

Hi Terry.

I finally got to flushing the lines.
Flushed the lines and got some nasty sludge spitting out the hoses.
So, before I move on to vacuuming the lines....
how much oil should I add, and where?
My system currently has PAG oil.

Thanks.

[Terry Kay]

<<Flushed the lines and got some nasty sludge spitting out the hoses.>>
You purged & flushed the lines with the air dyer alcohol both ways?
Blew the alcohol through the lines both ways with compressed air?
This is really important.
The garbage that flies outa them lines usually is nasty.
You wonder how the system was working at all with all that snot in it slowing the flow of refrigerant down.

<<So, before I move on to vacuuming the lines....
how much oil should I add, and where?>>

Some Sanden AC compressor's hold oil in the body of the compressor, some just use the oil floating in the system.

If there is no drain plug in your's--suck the system down first, let it sit for an hour or two to see if the system wil hold the vacuum, and then put one can of Pag oil back in it--
A can of oil is usually 2-3 ounces.
And seeing as you didn't drain the compressor, one can will be plenty.

<<My system currently has PAG oil.>>

I'd stay with the PAG oil, seeing as you didn't flush out the compressor--and this is OK, just as long as you don't blow mineral oil in the lines.

After you get the oil back in the lines, introduce whatever freon of you choose--other than R-12--it won't work with the PAG oil.

I sure do like the Red Tek (R-12-A) refrigerant, mostly because it works well at lower pressure, and isn't as hard on all of the antique operating component's in the system.
Plus it blows a bunch cooler than the 134-A.
( and it's a better deal )

Good Luck,
_________________
T.K.

[vagonan]

Thanks for the quick response!!
I'll pick up a can of PAG tomorrow.
Hopefully, I'll be able to finish up over the weekend.
That box of REDTEK has been staring at me for a while now.
Looking forward to giving it a try.

[kayakwesty]

hey terry

after all that should he replace the dryer?

the reason I ask I might do this to mine to make mine colder


Mark
_________________
1984 Westy 2.0 Jetta ABA Motor/1.8 head converted to auto tranny, with 180,000 on body, 55K on engine and transmission

B.5.5 Passat Wagen with 30v V6-67000 Miles

DAS AUTO

CHANGE YOUR FUEL LINES!

A post without pictures is useless

http://www.kayakwesty.com

http://www.waldensridgewhitewater.com/

[funagon]

I shareTK's good opinion of Redtek.

I recently had my non-functional A/C system converted to 134a and that was an inadequate solution. I had the job done by a good shop who I trust--and they convinced me that 134 was the way to go--with new compressor and reciever dryer. With 134 the A/C was only lukewarm when the temps went over 90 (when I really need it). And the compressor stole so much power from the engine that I had to shut off the AC just to accelerate.

Switched to Redtek and now the AC cools the van in 100 degree heat, and I can leave it on while driving up hill. Still draws a little power from the lil waterboxer but nowhere nearly as noticeable as the 134 did.