Engine Cooling problem
1995 GMC C1500 V8 Two Wheel Drive Automatic 119k miles
I've ran into an odd situation I could use some help on. 1995 GMC C1500 5.7 with 119k miles. Newish water pump (5-7k miles), new radiator (replaced single core with dual core), new 195 deg. Thermostat and Hayden severe duty fan clutch.
All is fine as the truck warms up. As soon as the thermostat opens @ approx 195, the temp drops to ~150 deg. After a few minutes starts to climb again until it hits the 195, then drops to 150 and the cycle repeats itself. Doesn't seem to matter if I'm on the road for 1/2 hour or 4 hours, the temp won't hold at 195 and constantly bounces off the thermostat. I've had 3 different thermostats in the vehicle, 1 regular Stant 195 deg, a Stant Super Stat 180 deg and the current Super Stat at 195.
It seems to me that this would wreak havoc on the fuel injection system and I'm hoping is partially to blame for recent plummet in fuel economy.
Any insight would be greatly appreciated.
Tuesday, April 15th, 2008 AT 8:59 AM