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  #1  
Old 07-01-2016, 02:20 PM
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W126 Expansion Valve Tutorial?

Working on a friend's 1984 280SE (Euro spec) with the M110 six. Replaced the bad clutch on the (York/R12) compressor and topped the system off with Freeze 12.
Pressures seem good (170H, 40L) but very little cooling from the vents. Leads me to believe defective expansion valve.

Apparently could be the aluminum block expansion valve or the old style brass/copper bulb type.

Is there a tutorial for replacing the expansion valve?

Or am I barking up the wrong tree?

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  #2  
Old 07-01-2016, 06:41 PM
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Any history on this car?

If the expansion valve was not opening enough, the high side would be going very high and low side very low / suction.

Is the large hose leading from the evaporator to the compressor cold maybe frost covered? If so , the expansion valve is working.

You might have a stuck open heater valve / blend door staying in the hot position. Feel both heater hoses, are they of equally hot temperature? If so the heaver valve is open.
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Old 07-02-2016, 01:13 PM
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Quote:
Originally Posted by 97 SL320 View Post
Any history on this car?

If the expansion valve was not opening enough, the high side would be going very high and low side very low / suction.

Is the large hose leading from the evaporator to the compressor cold maybe frost covered? If so , the expansion valve is working.

You might have a stuck open heater valve / blend door staying in the hot position. Feel both heater hoses, are they of equally hot temperature? If so the heaver valve is open.
The high side line is noticeably warmer than the suction line but the suction line isn't cold.
No history on the car, came to me with a bad compressor clutch but free compressor and some refrigerant still in the system.
Replaced the clutch and topped off the system.
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  #4  
Old 07-05-2016, 05:10 PM
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Freeze 12 never worked well in my experience, I seem to recall it being a mix of R134A and other crap. Was this in the system before the top off? If you have no idea, it could be full of ambient air for all you know. BTDT with unknown vehicles.

You do not have a TXV problem.

You have an inefficient condenser with tiny aux fan, this is the major issue. Go back to R12 or try R152A.

Were your pressures checked at high idle? Aux fan working? How about that fan clutch?

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