Fan Clutch
Logistics Pro
Joined: Jul 2003
Posts: 3,595
Likes: 52
From: Lawton, Oklahoma
The best way is to hook up a high pressure guage line to the air conditioning system and watch the pressures on the high side. If they run well over 300 psi to 450 psi with the AC on and the condenser is clean you arent getting enough air flow from the fan clutch. It will cycle off the AC on late model vehicles from the high pressure cut off rather than from the low side pressure or evap temp. Otherwise watch the fan speed at full operating temperature and see if the fan just spins slow at open throttle. At idle a bad clutch will hardly pull any air at all but it can be partially bad and seem to work fine till you get some higher rpms on it and then just go gutless. It can be difficult to guage unless you use the AC system as I suggest.
