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name this part

BMW 635CSi on Sat June 27, 2009 12:29 AM User is offline

Year: 1986
Make: BMW
Model: 635CSi
Engine Size: 3.5
Refrigerant Type: R12
Country of Origin: United States

Hopefully the pictures will work.
No one on the BMW forums can say EXACTLY what this part is or does.
I have a 2 evaporator system, front and rear. To get the freon to the rear
it must pass through this valve. Single evap cars do NOT have this valve.

It is NOT the expansion valve, Both of those are on the respective evaporators.

What is it called and what does it do?
(free Slurpee for the correct answer)

http://www.autoacforum.com/forumimages/IMG_0227.jpg

Matt L on Sat June 27, 2009 2:00 AM User is offline

I can't tell you what it is called or even what it does, but boy, does that look expensive.

TRB on Sat June 27, 2009 11:37 AM User is offlineView users profile

My guess is it is a temperature control (pressure) device for the rear unit.



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torque395 on Sat June 27, 2009 3:22 PM User is offline

Quote
Originally posted by: Matt L
I can't tell you what it is called or even what it does, but boy, does that look expensive.

Its BMW. Its ALL expensive. lol.

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1996 Chevy Suburban 2500 4x2 6.5L Turbo

94RX-7 on Sat June 27, 2009 4:45 PM User is offline

How many wires go to it? What does the control circuitry for it look like? This is on the liquid line I presume?

I'm guessing it is a simple solenoid valve that is either on or off, open or closed....although it is hard to tell since there's no frame of reference as far as size is concerned.

BMW 635CSi on Sun June 28, 2009 2:46 PM User is offline

No electrical power to the unit.
Just a port for the capilliary line to the front expansion valve.
Keep trying, I would really like to know

94RX-7 on Sun June 28, 2009 3:31 PM User is offline

Can you show a picture of the device installed in the car? Can you post a picture of exactly where and what the other end of the capillary line attaches to?

My guess would be some sort of suction throttling valve, but you said the liquid going TO the evaporator goes through this device and a STV would be for gas coming FROM the evaporator.

Is that a service port under the black cap?

BMW 635CSi on Sun June 28, 2009 4:19 PM User is offline

There is a service port , that is where the black cap is.
behind that is the neck for the expansion capillary.
There is a large fitting in and out.

The rear cylindrical unit has a pre tensioned spring. There is also
a rubber diaphram in there.

bohica2xo on Sun June 28, 2009 5:55 PM User is offline

It is an STV. It keeps the rear evaporator from turning into a block of ice when you turn the rear fan off.

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.

mr2madlad on Mon June 29, 2009 7:23 PM User is offline


I think this parts name is Bob !

Its and STV valve these were typically used on older A/C systems and have been replaced because of fixed orifice tubes and cycling compressors on newer systems.

An STV Valve (Suction Throttling Valve) is located near or at the evaporator outlet, it controls the amount of compressor suction and therefore the refrigerant flow through the evaporator.

When liquid refrigerant enters the evaporator it boils and changes state to vapor, that vapor is "pulled" from the evaporator by the compressor's suction.

If there is too much suction on the evaporator the pressure and temperature will become too low causing it to freeze any condensation gathered and block its fins reducing air flow.
If there is too little compressor suction on the evaporator the pressure and temperature will not be low enough to maintain proper cooling performance and your get warm air.

Mr2madlad





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The man who makes things, or breaks things, you decide.

94RX-7 on Mon June 29, 2009 7:34 PM User is offline

Quote
Originally posted by: BMW 635CSiTo get the freon to the rear

it must pass through this valve.

I think you owe the whole board a slurpee. Your description was faulty...should've read to get the freon FROM the rear....

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