Automotive Air Conditioning Information Forum (Archives)

johnboy_x86 on Wed August 10, 2011 9:10 PM

Year: 2005
Make: Chrysler
Model: Town and Country
Engine Size: 3.8
Refrigerant Type: R-134a
Ambient Temp: 85
Pressure Low: 100+
Pressure High: ???

According to the sticker on the fan housing, my system should hold 2.53lbs. (It has front and rear air). A quick calculation showed that I'd need a little over 3 of the 12-oz cans to fill it up. I bought three cans, plus a 3-oz can of oil.

After charging the oil as the can recommended, I charged with the first can of freon. (Again, according to the instructions on the can: Vehicle running, can upright.)

The system didn't seem to want to take all of the freon; after 15 minutes, I still ended up wasting what seemed to be at least half of the can.

At this point, the vehicle is still blowing hot air, although I can now hear the compressor engaging. I put the gauge on the low side, and it read over 100psi! That's after wasting at least half of the can!

Can anyone offer any guidance?

Thanks in advance...

GM Tech on Wed August 10, 2011 9:27 PM

So did you start with a vacuum in system, or are you trying to top it off? Sounds like el cheapo gage connector is not depressor low side ball valve....100 psi is can pressure, not low side- since ball valve is not opening IMO. You may need a real set of gages.

-------------------------
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

DaveMcKenz on Wed August 10, 2011 9:36 PM

JJM on Wed August 10, 2011 10:08 PM

Best guidance is not to use those recharge kits, otherwise what could've been an inexpensive repair turns into a TSR (Total System Replacement).

What makes you think the system needed to be "filled up"?

Joe

johnboy_x86 on Thu August 11, 2011 10:53 AM

Yes, it is an el-cheapo, although at least it is a separate hose/gauge! (Not bought with a can)


OK, here's the whole story:

AC was working, but seemingly inadequate. I assumed the system was a little low on freon, but couldn't find the gauge at the time (one week ago).

I attached a can, and the system SUCKED the can in...Fastest I ever experienced...I'd say less than two minutes. AC ran fine for a day or two. Then, it stopped cooling altogether.

I found the gauge, and measured.....WAY high low-side pressure (140-170 IIRC). I release some pressure to get it below 40. Still nothing but hot air.

So then, I released it all (lo-tech, into the atmosphere), and that's where this thread starts....

Thanks so much for all of your responses...It's great to hear from professionals. Any advice is appreciated...!

-JR

johnboy_x86 on Thu August 11, 2011 11:35 AM

I just remembered....This hose can either fill, OR gauge....You take the gauge off the end.

Sooo...It's not measuring the can pressure....It's only hooked up to low-side...

The mystery deepens...

bohica2xo on Thu August 11, 2011 11:45 AM

Do you recall exactly what was in that can that "sucked in " so quickly? a brand name perhaps?

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

johnboy_x86 on Thu August 11, 2011 11:47 AM

Man, I don't...It was a cheapy from one of the "Dollar" stores...

It had dye in it, I remember it spilling out when I lowered the pressure...

bohica2xo on Thu August 11, 2011 12:02 PM

Too bad you don't still have the can.

With a static pressure of 170 psi, whatever was in that can was not 134a.

Is the compressor clutch engaging?

.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

johnboy_x86 on Thu August 11, 2011 12:38 PM

Well, I can find the brand I'm using now....Like I said, half of the can, plus the oil, took the pressure into the red as well. I was suspecting the compressor not doing something correctly, and causing the readings to be similar to what they would be with the car off.

As for the compressor...I hear the "click", and the engine seems to take on a load, so is that enough to say "Yes"?

-JR

bohica2xo on Thu August 11, 2011 1:25 PM

Going to be an expensive trip to the dollar store.

You either need to buy a set of decent gauges, and begin troubleshooting properly, or take the vehicle to a shop.

Likely you will need to go the TSR route from your story. A/C systems will not tolerate shortcuts or the introduction of whatever industrial waste some chinese factory can dispose of in a can at the dollar store. I really wish the feds would spend some time going after the magic in a can outfits.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

bohica2xo on Thu August 11, 2011 1:25 PM

Going to be an expensive trip to the dollar store.

You either need to buy a set of decent gauges, and begin troubleshooting properly, or take the vehicle to a shop.

Likely you will need to go the TSR route from your story. A/C systems will not tolerate shortcuts or the introduction of whatever industrial waste some chinese factory can dispose of in a can at the dollar store. I really wish the feds would spend some time going after the magic in a can outfits.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

johnboy_x86 on Thu August 11, 2011 8:22 PM

Stresst on Thu August 11, 2011 8:23 PM

What do you mean when can you lowered pressure in an a/c system by "releasing some pressure"? I was once told an a/c system is not like a tire on your car. If you overcharge you need to evacuate and reinstall. IDK


-------------------------
2000 Cadillac Escalade w/rear air

johnboy_x86 on Thu August 11, 2011 8:24 PM

OK, if it helps, it never got to 170...

I put two more cans in it, bringing my total weight to around the system weight (2.38 lbs), once you factor in the oil.

The low side pressure is now about 110. Of note, it was 100 before the final can, and "forcing" the final can in got it to about 110.

TSR?

JJM on Thu August 11, 2011 8:41 PM

If you released all of the refrigerant, the system needs to be vacuumed, otherwise you'll likely end up with air in the system, which is non-condensable resulting in excessively high pressures.

Oil is not factored as part of the total refrigerant charge. What type of oil was used?

If the low side pressure was 100 or 110 PSI with the compressor running, it's probably done, since a properly functioning compressor with low side pressures that high would be generating high side pressures high enough that would trip the HPCO.

I too think this looks like it'll end up a TSR (Total System Replacement)... which is unfortunate since the original problem was likely an inexpensive and simple fix.

Kit did its job.

Joe

johnboy_x86 on Fri August 12, 2011 1:46 PM

If it tripped the HPCO, will it reset?

As a last resort, perhaps I can vacuum out the system, and start over (oil charge, + three cans).

I think the oil was PAG. 1oz oil, 1oz freon, 1oz "conditioner".

mk378 on Fri August 12, 2011 1:56 PM

HPCO switches are designed to reset themselves and start the compressor again when the pressure falls. Relief valves may not always reclose if they pop open.

Don't add any more oil. You've been adding oil at every turn, which is not good.

You do need to start from vacuum and install the proper charge by weight. Again, use plain R-134a, no oil.

johnboy_x86 on Fri August 12, 2011 2:34 PM

Cool...Thanks, MK!

I will vacuum, and add three cans. No oil.

And pray.

JJM on Fri August 12, 2011 8:08 PM

What grade PAG oil are you using?

Agree with MK378; you probably have more oil in there than the Strategic Petroleum Reserve.

Joe

johnboy_x86 on Tue August 16, 2011 2:30 PM

Thought I'd give you guys the final outcome....

Took it to a trusted mechanic for the work. It turns out the clutch was bad on the compressor. He replaced the clutch (which came with a new pulley and bearing), and vacuumed/refilled the system.

$610...

Thanks for all of your help! I'm kindda interested in buying some gauges, and trying my hand at this. It would be more tempting were it possible to flush these new high-effiency evaporators....

-JR

Edited: Tue August 16, 2011 at 2:34 PM by johnboy_x86

GM Tech on Tue August 16, 2011 2:48 PM

Little steep for a clutch only job---you could have gotten a new pump (and clutch) for less than that.

-------------------------
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

TRB on Tue August 16, 2011 3:16 PM

NickD on Tue August 16, 2011 4:07 PM

I come to this board both to learn and to help.

On this thread, I learned something.

Didn't know these dollar stores sold cheap gauges.

Thought they just sold dollars.

JJM on Tue August 16, 2011 11:51 PM

$610!!! And here you were worried about wasting a half a can of $7 refrigerant? You could've bought all the tools you needed to service the system, clutch or even the whole compressor, and still come out ahead... and you'd have the tools for future repairs.

Joe