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  #1  
Old 07-13-2008, 11:32 AM
oso oso is offline
'87 300TD
 
Join Date: Oct 2007
Location: San Antonio, TX
Posts: 189
a/c question

Yesterday I had a guy tell me he could fix my a/c problem: compressor shutting of after a few minutes. He said it would need the expansion valve flush. I have the '87 300TDT and freon level or belt slipping are not the usual suspects.

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  #2  
Old 07-13-2008, 11:41 AM
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Does the a/c operate normally for 5-10 minutes, then the compressor disengage and not come back on for an extended period?
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  #3  
Old 07-13-2008, 11:45 AM
oso oso is offline
'87 300TD
 
Join Date: Oct 2007
Location: San Antonio, TX
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Quote:
Originally Posted by tangofox007 View Post
Does the a/c operate normally for 5-10 minutes, then the compressor disengage and not come back on for an extended period?
Correct.
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  #4  
Old 07-13-2008, 11:57 AM
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Then I would suspect the evaporator temp regulator. It is supposed to disengage the compressor to prevent evaporator freeze-up, but it can fail so that it "trips" at a too-high temp. You could unplug it and jumper the plug and see if that solves your problem.
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  #5  
Old 07-13-2008, 03:49 PM
sixto's Avatar
smoke gets in your eyes
 
Join Date: Jun 2000
Location: Eastern TN
Posts: 20,841
Could also be a temperamental Klima relay or low pressure switch.

Sixto
87 300D
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  #6  
Old 07-14-2008, 10:22 AM
oso oso is offline
'87 300TD
 
Join Date: Oct 2007
Location: San Antonio, TX
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Quote:
Originally Posted by sixto View Post
Could also be a temperamental Klima relay or low pressure switch.

Sixto
87 300D
No easy way out, as always....
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  #7  
Old 08-23-2008, 04:11 PM
oso oso is offline
'87 300TD
 
Join Date: Oct 2007
Location: San Antonio, TX
Posts: 189
Quote:
Originally Posted by sixto View Post
Could also be a temperamental Klima relay or low pressure switch.

Sixto
87 300D
Today I broke down and bought a new KLIMA relay- you were right on with the guess regarding a "temperamental" relay! Just a side observation: after I had a new unit in and a/c blowing cold air, I decided to take a look at the old one. It looked like it may have a darker spot on the board: how could it have happen with just 12v passing through?
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  #8  
Old 08-24-2008, 01:53 AM
compress ignite's Avatar
Drone aspiring to Serfdom
 
Join Date: Feb 2004
Location: 32(degrees) North by 81(degrees) West
Posts: 5,554
Don't DO This !

12Volts D.C. ain't anything like A.C...12 volts D.C. will stop your heart!
12 volts D.C. is enough power to weld a wrench dropped so that it contacts
both poles...
12 volts D.C. will turn the tip of a glow plug so cherry red that you can brand
cattle with it for about 5 minutes (AFTER it's disconnected).

Think about it this way: Alternating Current switches Polarity back and forth.
Direct Current is just straight power...
__________________
'84 300SD sold
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  #9  
Old 08-24-2008, 11:17 PM
oso oso is offline
'87 300TD
 
Join Date: Oct 2007
Location: San Antonio, TX
Posts: 189
Thanks to "compress ignite" another lesson learned! Hopefully you'll be around for many more of my "how come...." posts. Appreciate the straight up help.

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