This morning on the way to work, about an 8 mile drive, the engine light and ETC light (solid) came on about 1/2 mile from work. I also noticed that the temp gauge was not working. When I got to work and opened the hood the engine was covered in coolant and the radiator cap was loose. I took a company truck to the parts store and got a new cap and coolant. It is almost full after two gallons of coolant. When I restarted it the ETC light was off but the engine light was still on. The problem is that the engine began to overheat while idling. The upper radiator hose got stiff but not very hot. Also, there is a hissing noise from the drivers side of the engine bay, I do not know if this noise was there before or not. Any ideas about the overheating?

 

John:

My guess is that the lights you saw on the dash are due to the coolant spraying over everything.

When filling the system backup, leave the cap off and idle it with the heaters (front and rear if you have it) on full blast. Continue to top off and bump the RPMs up to 1.5-2k several times to help move air up to the filler where it can exit.

If you are overheating during this process, could be a bad thermostat or a failing fan clutch.

Don