Automotive Air Conditioning Information Forum (Archives)

bigkev on Mon August 06, 2012 2:22 AM

Year: 2003
Make: dodge
Model: durango
Engine Size: 4.7
Refrigerant Type: r134
Ambient Temp: 70
Pressure Low: 100
Pressure High: 125
Country of Origin: United States

A Durango im working on had no ac when I first looked at it. I checked the pressures and noticed that both sides was almost the same pressure with the compressor running. I figured the expansion valve must be bad on it. I put a new expansion valve on it, vacuumed, and refilled. Now the pressure is about the same but it seems like I get some cool air out the back vents and almost none out of the front vents. The compressor is not making any weird noise nor has it. I wonder if its possible I was sold the one for the durango without rear ac, Ill check that in the morning. I noticed on some auto parts websites they list a front and a rear expansion valve. Has anybody replaced the rear valve or know where it is?

bigkev on Mon August 06, 2012 2:43 AM

After looking online it seems that it does have a rear ac expansion valve. It would make complete sense for the back one to be stuck open causing the front to not get cool at all and the back to get a little cool. Does anybody know where the expansion valve is located for the rear unit? I guess if nobody knows ill start following lines tomorrow.

bohica2xo on Mon August 06, 2012 11:44 AM

Kev:

Run the engine speed up to 2500 rpm & see what you have for pressures. That vehicle should have an SD7 compressor, which will pump enough volume at that speed to over run a wide open TXV

If you have the same pressures at 2500, then the compressor is toast.

B

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"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.

Edited: Mon August 06, 2012 at 11:46 AM by bohica2xo

GM Tech on Mon August 06, 2012 12:25 PM

rear expansion valve is at the entrance to rear evaporator- under all the plastic covers


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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......

bigkev on Wed August 08, 2012 1:47 AM

How much should it overrun? I did rev it a few times when checking pressure and it did slightly increase. Also ty gm tech for location.

bohica2xo on Wed August 08, 2012 2:36 PM

Kev:

With a full charge it should be able to provide cooling to both expansion devices @ full load. You should have seen less than 50 psi on the low side & closer to 180 on the high side if it was pumping.

Looks like a reed valve failure. Just not pumping much. A badly worn compressor with working reeds will produce cooling at higher speeds.

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.

ice-n-tropics on Wed August 08, 2012 9:06 PM

FYI,
Durango had a 33% warranty on compressors which was caused by the ETN rear expansion valve which had the metering pin off center. The counter measure was a Japanese TXV.
hotrodac

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Isentropic Efficiency=Ratio of Theoretical Compression Energy/Actual Energy.
AMAZON.com: How To Air Condition Your Hot Rod

bigkev on Fri August 17, 2012 2:28 AM

compressor wont overrun itself much at all so I guess it must be toast as you guys said. Im going to put a compressor on in the next couple days and I'll let you all know how it goes.

NickD on Fri August 17, 2012 7:56 AM

Is the expansion valve the culprit or the victim? More than likely the victim, but flip a coin. Recall a recall sometime in this era on poor evaporators, did you check the surfaces for oil leakage?

Note my local library has quite a selection of DIY repair books, most state you are looking for a single problem, an idiot writing a book for idiots. An AC is a system with a chain reaction characteristic. Have to evaluate the entire system and judge whether repairs are feasible or not.

Had a conversation with my son last night about his 2002 T&C with 96K on it with numerous problems, AC was only one of them. Book value was $1,700, repair cost having it done was $4,700, but then would soon experience head gasket problems. Just get rid of it, that is what he did. Major problems was in the transaxle followed by ten years of driving in road salt, so not only evaluate the systems, but the entire vehicle as well. He managed to get buy with 18 cents per mile depreciation, really not that bad in this day with all throwaway stuff.

For us hard working people, nothing could have been worse for us than that crazy clunker program, a whole new ballgame now, leaving most of us in left field if even in the ballpark.

bigkev on Thu September 13, 2012 12:31 AM

Thanks guys, sorry it took so long to get back, compressor did the trick cools like a new one. Old compressor had no abnormal noises and felt good when I turned it, no shavings anywhere either. Thing must have a busted reed inside it, maybe ill get bored and tear it apart just for fun. Thanks again!

Edited: Thu September 13, 2012 at 12:32 AM by bigkev