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Old 05-10-2010, 09:19 AM
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Cal Learner Cal Learner is offline
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Join Date: Aug 2006
Location: Marysville, CA
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Quote:
Originally Posted by LarryBible View Post
Test the fan clutch by simply turning the fan with the engine off and see if it coasts. If it does, replace the fan clutch.

The electric fan is actuated by high side a/c pressure and will not come on unless the a/c is on and the high side pressure is dangerously high. It's only purpose is to bring down that dangerous high side pressure.
True, but not the complete answer. It is also activated by the blue base temp sensor on the head, back about cyl 4 (farthest right in the photo). That's what activates the high fan at about 105C, while the pressure switch on the drier responds to condenser pressure (somewhere between 16 and 20 bar, depending on red or green switch).
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103 Engine Fan not cooling properly-p4105070x.jpg  
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1988 California version 260E (W124)
Anthracite Grey/Palomino
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Past Mercedes-Benz:
1986 190E Baby Benz
1967 230 Inherited from mom when she downsized
1959 220S Introduced me to the joys of keepin' 'em goin'

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