2002 3.0 auto xtype. To start the car since I’ve owned it has always ran temp wise right before the halfway point on the gauge. A couple months ago discovered I had a small leak and it was in the thermostat upper housing right under the air box so I bought the whole assembly from SNG and replaced it which also included the thermostat and all. Yesterday was driving home and boom high engine temperature and the gauge pegged out. Pulled over opened the hood and it was hissing from the over flow jug so it was hot also fans were running as normal. Started car back up and turned the heat on and the heater was blowing cold. Got it home and first thought was cold heat and over heating is usually the water pump. And I was right. Took out the pump and the impeller was shattered. Changed out the pump and refilled but that’s when more problems started. Car still over heats. Could it be possible that a piece of the impeller broke off and got thru the system and lodged the thermostat to where it won’t open ? I can piece it together but however I’m missing one of the fins. Heat works great now after the pump change.

 

Tony, I would start looking down stream. If you can get your hands on a boroscope, that may prove to be well worth any money that you spend on it. That willl let you look down the water channels and figure out where the impeller piece went. Sure beats trying to tear everything apart to find that one piece. But, odds are, you are going to find the impeller piece in the thermostat. Granted, could have made it to the radiator. But, I don't think that would have resulted in the motor overheating.

Wish you luck in finding the impeller piece.

 

Thanks Thermo for the suggestion. I found what was still making it over heat and it’s all good now. However I never found the impeller fin. By the looks of the pump it looks like it’s been gone for a while. The problem was when the water pump gave up its ghost that when it over heated the thermostat gave up at the same time. I’ve read here and there that the thermostat is basically a one over heat and it’s toast. It was only a few months old as I replaced the whole hose and thermostat assembly it also had the thermostat included from SNG. Well in the lower half of the thermostat there is a piece that has 3 braces coming from the walls to a round piece in the center that the pin from the thermostat goes into that it pushes against to open but when it got hot two of the 3 broke and allows the round part to drop down away from the pin therefore the thermostat couldn’t open at all. I back flushed for a good hours from every hose that I could get to easily and the missing fin never came out. Got a new thermostat from Autozone and installed & refilled and it’s been fine every sense.