Replaced both temperature sensors (to gauge and to ECM) at water pump. Cleaned electrical contacts in sensor plugs.
The temperature gauge rises upon starting cold to stay mid-range. Both the top and bottom radiator hoses become very hot and eventually the coolant boils sending steam to the overflow reservoir. The temperature gauge stays mid-range.
The engine idles and runs well. I can stop the boiling and steam venting in the reservoir by turning on the AC thus starting the fans.
I have not replaced the thermostat.
Friday, July 27th, 2012 AT 7:10 PM