[mgarblik]

Most likely a goofy thermostat is the issue. Been seeing more and more inconsistent, malfunctioning thermostats in the last 3-5 years than in my entire career. To try and combat this, I tried several of the safe-T stat type thermostats. That did not solve the issue. Just ended up with them latched in the open position. So that's not a fix. If a fresh thermostat doesn't seem to fix it, consider purchasing an infra-red temperature gun for better diagnosis. They are a handy little tool and Harbor Freight has decent ones for around $40.00. A good working cooling system should have about a 20 degree drop on the inlet hose, (lower) vs the upper hose once up to temperature. I doubt the water pump is the problem in this situation. If you have a quality pump, cast impeller, decent plate clearance, good, tight fitting rubber sleeves in the transfer tubes, there really isn't anything else in there to give you trouble.