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I'm back...for 3 weeks anyway

badufay on Sun April 06, 2008 5:53 PM User is offline

Year: 1998
Make: VW
Model: Golf
Engine Size: 2.0L
Refrigerant Type: R-134a
Ambient Temp: 80° F
Pressure Low: 85 psi
Pressure High: 90 psi

Hey guys! Im back on a little break from Iraq about 3 weeks before I go back for another 8 months (ehhh). To keep on topic of a/c, my Golf doesn't blow cold anymore. the temps and the pressures are all equal at about 85 ish, with little or no change when the engine is accelerated. The clutch is engaging, but all the lines are still warm (on all sides of the expansion valve). I evac'd and charged the system, with no change...(no leaks). I think I might have screwed up the RCV when i replaced it last year. Any ideas?

Ben

TRB on Sun April 06, 2008 7:13 PM User is offlineView users profile

My first guess would be a defective control valve. That is as long as the clutch is engaging.

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When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com

Chick on Sun April 06, 2008 8:52 PM User is offlineView users profile

Ditto on the control valve, unlike GM variable compressors, the Sanden will show "almost" equal pressures when the control valve sticks.. , but you could try hitting it with the engine on fast idle, use a stick, avoid the fan and belts, and hit the stick with a hammer to see if it frees up, not the "professional" way to test it, but I have whacked a few and had them start pumping again..Don't hit it so hard as to break the aluminum case though... If it frees up and starts working, it will be short lived anyway, I'd look into replacing it when you get back

Thank you for your service to our country...

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

ice-n-tropics on Mon April 07, 2008 10:02 AM User is offline

Ben,
You came back to Texas to cool off? See any 130 F?
If the A/C worked after you replaced the CV together with the valve plate (mounted as an assembly), then you didn't screw up.
If the old replaced valve had trash/contamination on it's screen/inlet opening, then the same root cause of the original failure is ditto and you may need to flush the entire A/C system and clean the CV screen.
Thanks for all you do to reduce terrorism.
Cordially,
Old IV guy

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

badufay on Mon April 07, 2008 1:42 PM User is offline

ok, well i pulled the rcv out this morning and placed just a bolt in there to see if that was the cause. Put everything back together, charged it up, and nothing. Low side sits at about 75-80 psi, high side sits at about 90 psi. temp outside is about 80°F, Compressor does engage, but the gauges show little or no reaction to cycling the compressor on and off. Any more ideas? Im assuming the expansion valve isnt the problem, but rather the compressor again. Ice-n-tropics, havent seen 130° yet, but we have broke 105...keep in mind it is only April too. The summer came quick over there, but at least I dont have to drive my non-ac car in iraq right now.
Ben

ice-n-tropics on Mon April 07, 2008 4:08 PM User is offline

Ben,
Long ago removed the large o-ring which seals the CV into the cylinder block counterbore to allow more bypass gas from the discharge chamber into the crankcase. This should lock it into full stroke without bypassing all the gas. It'll be noisy at high rpm and may not last very long w/o crapping itself.
Cordially,
Old IV guy

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

badufay on Mon April 07, 2008 4:19 PM User is offline

nothing changes at all when the clutch engages (as far as pressures). The engine doesn't drop in idle like it used to, but the clutch is definitly engaging. I did notice i am able to turn the clutch by hand with no resistance at all when the car is turned off. The bolt didn't make any difference at all...so even with the compressor at full stroke, there is no change in the pressures. would any expansion valve problems cause this? what about the air gap on the clutch? how do you check that, and how do you adjust it? If i can find out the cause of the problem i can put the RCV back in the compressor and be happy with it. any help is always appreciated.
thanks,
ben

TRB on Mon April 07, 2008 4:36 PM User is offlineView users profile

Compressor/control valve is shot in my opinion.

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

When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com

ice-n-tropics on Tue April 08, 2008 9:11 AM User is offline

Ben,
I'm having a hard time picturing what would happen if you replaced the CV with a bolt. Does a metered amount of discharge gas flow into the cylinder block to raise the force on the underside of the pistons? Higher crankcase pressure = greater stroke and displacement.
Maybe the way you placed bolt/washers blocked communication with crankcase.
Want to try my suggestion by reinstalling CV to allow a little high pressure bleed to crankcase and removing 3/4" o-ring between CV and block? Just for a quick test.
Got any contamination on inlet to new or old CV?
Cordially,
Old IV guy

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

badufay on Tue April 08, 2008 11:35 AM User is offline

ill try to remove the o-ring, the procedure that i am talking about is this...

http://www.aircondition.com/tech/getattachment.php?data=NTN8UmVmcmlnZXJhbnRfQ29udHJvbF9WYWx2ZXMucGRm

this is what i did....there was absolutely no change with the bolt installed and when the rcv was in there. like i said, ill try the oring unless you think it will not work.

ben

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