I drive a 94 mitsubishi mighty max 2-wheel drive truck.My engine is a 4-cylinder 2.4liter.It has 93,000 miles on it.My thermostat closed up the other day and my truck started to overheat I was heading home so every couple of miles I would stop and let the truck cool down but I think I still may have damaged the engine.I replaced the thermostat and refilled the antifreeze and water.I let it idle for about 15-minutes and it stayed cool and didn't overheat.When I drove home from work the next day it started to overheat again and felt like it has lost a lot of power like something is holding it back, the rpms will go up but the truck really has to struggle to acelerate.The last time I took the truck out it didn't overheat but it still has the same problem with acelerating.Any ideas on what may be damaged?Thanks for your help, Brian

You may have warped the aluminum head, resulting in lost compression. This is not an uncommon occurrence, which results in the head having to be machined, valve work done, and a new head gasket installed. I hope you are not facing this. Next to maintaining proper lubrication, maintaining the cooling system is the most important thing you can do for your engine. If you are not already, only use distilled water with the antifreeze recommended by the vehicle's manufacturer and change it every 2 to 3 years. Tap water and improper antifreeze can contribute to premature cooling system failure.