Thought I'd run this by the group to see where I may be failing.
1987 Isuzu Trooper II 2.3L ( Gasoline ) I4 with 170,000 milesI'm experiencing an over-heating problem along with some other symptoms that I have not run across before.
- Only on the first run in the morning. The dashboard temperature gauge indicates that the engine warms to almost full-scale deflection shortly after driving off. The gauge will hold that peak for 30 seconds or so and finally come back down to 'normal' operating temperature. This will not happen again while the vehicle is parked at work for 9 hours or so, but is pretty much a sure bet the next morning. ( Needs to be colder? )
- Coolant overflow tank will fill beyond its limit and spill coolant out of the lid. This will happen even if I start with the overflow empty (cold) and fill the radiator/block only.
My first thought was that the thermostat is sticking and finally breaking free. I installed a new one and the problem is the same or perhaps worse. I also thought that the belt driving the water pump may be glazed and replaced it at the same time as the thermostat. I've also added a new radiator cap because of cracks in the rubber on the original.
I have found no evidence of coolant in the exhaust or in the oil. This leads me to believe that the head gasket is probably not the problem.
Do any of you have a recommendation / guess as to where to look next?
Thanks!