If the engine temperature is rising when doing 80 mph, the problem is not the fan. The fan becomes redundant after about 30 mph. Most fan couplings disengage about 2500 rpm anyway. I would look further into cooling system problems.
I would work at it in this order: 1. Do you have any coolant loss? If you do, pressure check the coolant system and find the leak. You may have a cracked head or leaking head gasket. 2. If the cooling system has no leaks, check the lower radiator hose. Make sure it is not soft and collapsing at high engine rpm. Many of these have an internal spring (to prevent collapse) that may have eroded away. 3. Flush the cooling system. 4. Check the U-shaped metal line between the front of the head and engine block (or water pump?). It has a banjo fitting on each end. Make sure it is clean. 5. Have the radiator cleaned at a good radiator shop. If it is one of the cheap aftermarket ones replace it with a heavy duty radiator. 6. Check the water pump for vane erosion. If it is not OEM, replace it with an OEM pump. The OEM pump will pump at a higher rate. If none of this fixes the problem, move to New Jersey.:) Good luck, Thomas E. Potter Telephone: (713) 215-2877 Fax: (713) 215-2551 Mobile: (832) 794-0536 -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of BillR Sent: Thursday, September 29, 2005 3:03 PM To: [EMAIL PROTECTED] Subject: [MBZ] Terrified driving ...With the old engine it ran beautifully up to about 80, then it still ran beautifully but the temp gauge started an unhealthy climb. My son put on a flexible fan and checked the cooling system.
