Automotive Air Conditioning Information Forum (Archives)

Sevir on Sat February 12, 2011 9:26 PM

Year: 204
Make: Dodge
Model: Ram 2500
Engine Size: 5.9
Refrigerant Type: R134a
Ambient Temp: 50
Pressure Low: 30
Pressure High: ??
Country of Origin: United States

Copy and paste from my other forum and was directed to ask here:

A little background first. my compressor failed 6 months ago (clutch assembly) so nothing in the AC system failed, no catastrophic compressor failure. I didnt want to pay the $1000 price tag i was quoted to fix this so i did ALOT of research on AC systems. With all the research i did, i was able to replace my compressor/accumulator and orifice tube as per most the instructions i found saying to do this when opening the system to atmosphere. I also installed a inline filter that was recommended by all the reading i did. I flushed the system and blew dry nitrogen through it. After this everything worked and i had no problems. I put the recommended oil in per item removed. about 3 months later i started getting condensation on my windshield and a whoooooshing sound coming from the HVAC system. I recharged the system and it worked for about a few hours then started doing it again. After troubleshooting the system, the whooooshing sound was coming from the orifice tube. it sounds like air blowing through an airhose nozzle. Yesterday i replaced my orifice tube and accumulator, charged the system to 30PSI on the low side and i still have this whooooshing sound coming from the new orifice tube. When i removed the system yesterday, the oil looked good (not black). I spoke with the A/C mechanic and he is lost also why my orifice tube is making that sound. I have had my system on vacuum overnight and it held. The system has been holding a charge for a week now. I injected dye into the system and went looked at every part with a black light except the evap core for a leak with nothing found.

So i need some help here, what is causing my orifice tube to do this and why. Other then the sound, everything works. I have cold air coming out of my vents and the system is working as it suppose to. No leaks and its maintaining pressure. This is why i am asking for expert help from someone on here.

Dougflas on Sun February 13, 2011 3:33 AM

Where did you install the filter? What kind of filter is it? THe sound you're describing may be refrigerant migration and equalization.

Sevir on Mon February 14, 2011 10:46 AM

i installed it after the compressor and pre-condensor. i dont remember which one i used, put it on 6 months ago. there are no markings on it to identify the company and i threw away the invoice.

what is "migration and equalization"

Edit: i was able to find the one i bought. http://www.usatoolwarehouse.com/usatoolwarehouse/SRR-AC128.html

Edited: Mon February 14, 2011 at 10:51 AM by Sevir

mk378 on Mon February 14, 2011 11:59 AM

Sometimes, orifice tubes make noise. GM liked to mount them way up near the condenser so it is less noticeable in the cab.

Charge it by weight, not pressure.

Sevir on Mon February 14, 2011 12:54 PM

if it made noise outside of my cab i would be fine with that, but it is transmitting to my evap core. at first i thought i had a bad evap core but ended up being the orifice tube. It is incrediably annoying inside my cab. Even with my diesel engine rumble, my turbo spooling and my radio up i can still hear it and its driving me bananas.

kinda new still to HVAC, what do you mean charge by weight? since i have a 36oz system, put 36oz in it?

Edited: Mon February 14, 2011 at 1:38 PM by Sevir

HECAT on Mon February 14, 2011 2:42 PM

Those types of filters are usually installed in the liquid line after the condenser. Some of them also come with an orifice tube inside that needs to be removed.

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

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

FLUSHING TECHNICAL PAPER vs2.pdf 

Sevir on Mon February 14, 2011 3:44 PM

Quote
Originally posted by: HECAT
Those types of filters are usually installed in the liquid line after the condenser. Some of them also come with an orifice tube inside that needs to be removed.

your right and that is what i did. After i read your post i realized i did install it after the condensor. but i do know it does not have a orifice tube in it. i can see right through it. on a % scale, could this filter be the problem? i dont mind taking it out and putting a new line from the condensor to orifice tube, but if there is only a small chance this is a problem, i would rather try something else.

HECAT on Mon February 14, 2011 4:26 PM

Filter causing it, unlikely (less than 25%). Are you charging the full amount in by weight? What is the high side pressure?

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

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

FLUSHING TECHNICAL PAPER vs2.pdf 

bohica2xo on Tue February 15, 2011 4:01 PM

OK, so you did a compressor replacement 3 months back, and recently got "condensation on the windshield" and a new noise?

Does the condensation happen all the time? Any water leaks on the floor?

You "recharged they system" - then after 3 hours the problem returned?

Since I see a lot of holes here, there is some guesswork involved. The condensation may be a heater core issue, or a plugged evaporator drain issue.

You definitely have a leak. A "recharge" after 3 months is a bad sign.

A replacement compressor may have had a full system oil charge on board, or not. If there is too much oil in the system, performance will suffer. Too little and the compressor suffers. Vacuum is necessary to remove the air from the system, as well as moisture.

You can't charge by low side pressures alone. Best to charge systems by weight. A high side pressure reading is necessary for proper diagnosis of a system.

You state that you have cold air coming out of the vents - with a 50f ambient that is not hard to do, even if severely undercharged or overcharged.

You have a mess right now. It leaks. An unknown quantity of oil in the system.

Locate the evaporator drain on your vehicle. Check it with the black light. An evaporator leak will show up there. Check that the drain runs free, a blocked drain can lead to a wet windshield.

If you still can't find the leak, recover the system and charge a full charge by weight. Run the system a few days, and re-check everything with the UV light.

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.

Sevir on Wed February 16, 2011 1:51 PM

Quote
Originally posted by: bohica2xo
OK, so you did a compressor replacement 3 months back, and recently got "condensation on the windshield" and a new noise?

Does the condensation happen all the time? Any water leaks on the floor?

You "recharged they system" - then after 3 hours the problem returned?

Since I see a lot of holes here, there is some guesswork involved. The condensation may be a heater core issue, or a plugged evaporator drain issue.

You definitely have a leak. A "recharge" after 3 months is a bad sign.

A replacement compressor may have had a full system oil charge on board, or not. If there is too much oil in the system, performance will suffer. Too little and the compressor suffers. Vacuum is necessary to remove the air from the system, as well as moisture.

You can't charge by low side pressures alone. Best to charge systems by weight. A high side pressure reading is necessary for proper diagnosis of a system.

You state that you have cold air coming out of the vents - with a 50f ambient that is not hard to do, even if severely undercharged or overcharged.

You have a mess right now. It leaks. An unknown quantity of oil in the system.

Locate the evaporator drain on your vehicle. Check it with the black light. An evaporator leak will show up there. Check that the drain runs free, a blocked drain can lead to a wet windshield.

If you still can't find the leak, recover the system and charge a full charge by weight. Run the system a few days, and re-check everything with the UV light.

B.

Thanks for the input,
I know my timeline seems a little jacked, this is due to my military schedule and wonderful Seattle, WA. weather not cooperating and 6 months of forgetting stuff. basically i need to start from scratch which i dont mind. And now i can tell the wife i need to pickup some gauges for the HVAC system. (good news for me, more tools!) Does the HVAC manifold measure vacumm?
Let me know if this sounds right.
Recover the system
Evac the system, hold under vacumm for 1-2 hrs.
Check Evap drain plug and evap area for leakage
(The oil that is in the system is the amount recommended per removal of parts. Basically only the accumilator since the compressor came pre-oiled is all i added +2 17oz cans of R134a w/oil.)
then recharge the system with 32oz of r134a and not by pressure.

Let me know if there is anything i am missing or need to do.




Edited: Wed February 16, 2011 at 1:53 PM by Sevir

HECAT on Wed February 16, 2011 2:52 PM

Quote
Originally posted by: Sevir
(The oil that is in the system is the amount recommended per removal of parts. Basically only the accumilator since the compressor came pre-oiled is all i added +2 17oz cans of R134a w/oil.)

Stay away from the death kit cans (18 oz with oil and leak sealer).

Use the 12 oz cans of R134a refrigerant only (no additives).

First post stated you flushed; the system would have then required the full load of oil.

The compressor came pre-oiled. Was that shipping oil? A full system load of oil?

I agree with B. You have a leaker full of an unknown quantity of oil.

The Evaps in these trucks are common leakers.

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


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

FLUSHING TECHNICAL PAPER vs2.pdf 

bohica2xo on Wed February 16, 2011 3:04 PM

A gauge set or manifold does indeed measure system vacuum.

Once you get it evacuated, recharge it with the proper weight of 134a - no oil / magic in a can / sealer / etc.

Run it as much as you can for a week. The dye circulates with the oil, which is moved around by the refrigerant when things are running. The oil coats the inside of most everything when the system is stopped, so static leak will show dye if there has been plenty of circulation.

Re-check everything. This includes the compressor clutch area, the evaporator drain & every connection or joint.

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.

Sevir on Wed February 16, 2011 3:56 PM

12oz can with dye or no dye? right now i have a little 3oz can of die i just connect to the low side with a 3sec shot to inject die. Also, should i do another flush? also thanks for all the help on here. i am probably about even $$$ now instead of paying to get it fixed, but i learned alot about HVAC.

Edited: Wed February 16, 2011 at 3:58 PM by Sevir

HECAT on Thu February 17, 2011 6:38 PM

I would follow B's advice and find the leak first.

If it already has dye, it does not need more.

Flushing could be part of the final fix.

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

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

FLUSHING TECHNICAL PAPER vs2.pdf