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Old 10-08-2002, 04:01 PM
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jsmith jsmith is offline
Join Date: Aug 2001
Location: At Sea
Posts: 1,729
i've seen an application guide for using just such a noncontact ir temperature device to diagnose a clogged radiator. haven't seen a report of this beeing done on this forum though. it's literally point and shoot and you go over the entire radiator area to check & compare readings. i think removing the fan shroud might be sufficient.

i'd like to hear Chowpit's view on the fan clutch lock up issue since he mentions that the radiator, if clogged won't pass enough heat to lock the clutch. the bimetal strip that controls the locking supposedly triggers at 107C which will need radiant / convection heat from the radiator whose surface tmeps will have to be at 110-115C. the coolant will then have to be at around 120C for this to happen (BTW this is information from Stu Ritter, the tech ed over at Star mag). it certainly sounds like stock fan clutches never lock at normal temps.

i also keep reading about these "failed" fan clutches. i understand that shear characteristics of the clutch fluid deteriorate over time and eventually it will be slipping too much to provide sufficient cooling in its "freewheeling" mode (really a controlled slippage). as to evaluating a fan clutch - i saw the "spin it hard when cold" approach (no more than half a rev), to the shutdown of a warmed up engine (2 second spin down?). is there a correct procedure?
1993 300e-2.8
- gone now <sigh>
"Do not adjust your mind, it's reality that's malfunctioning"

Last edited by jsmith; 10-08-2002 at 04:40 PM.
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