hey guys im a new member here but have been reading this forum for a good long while always great help here! im kind of in a pickle and could use some help! about two weeks ago i purchased a nice little 2001 4.2 v6 standard tranmission 2wd truck for a fair price. needed a couple of minor issues fixed which i took care of the first couple days. after a bout a week and a half of driving i started to notice my temperature guage rising. i noticed that i had no flow in the cooling system so i tore it down and found that the impeller on the water pump had sheared off and was just sitting there. so i installed a new water pump and buttoned her back up thinking that this would be the end of my overheating problems... nope! while i had the radiator off and the water pump off i flushed thru the system with a water hose and thru the radiator from both ways and thru both heater hoses both ways. after filling the system up 50/50 with water and antifreeze and making sure i was at the right level i took it for a test run. i drove about six miles and saw the temp start to climb. i pulled over and let the pressure off of the de-gas bottle not recommended but i chanced it rather than fry my motor. as soon as i let off pressure it went right back down to cool and i started off again. i drove about 25 miles all together abd had to stop and repeat this process about three of four times. i just figured it was working trapped air out of the system. the problem is four days later its still doing the same thing always after about ten minutes of running(my commute time). am i missing something or does anyone know what would cause this? please help i cant go anywhere without pulling over every 10 miinutes... any input would be greatly appreciated!!! frustrated as all hades!! also my heater which didnt work previously now is coming and going... also replaced the thermostat and fan clutch...

 

Did you replace the thermostat?

 

yes as well as the fan clutch which was a little wobbly.

 

also checked belt routing, fan rotation blew thru all inlets and outlets with the hose when i flushed it.

 

Sounds just like low coolant. When you run it and it heats up, you need to let it completely cool, then add coolant to the surge tank. Repeat as long as it takes to get the air out and the coolant in.


OR: now this is weird, so let me explain what happened. I had an old Mustang once (1964 1/2 convertible with 260 V8 and a generator - wish I still had it! $$$). It did the same thing as your truck. I had the radiator flow-checked, replaced the thermostat, yada, yada, to no avail. It was okay around town but heated up on the highway, which usually indicates low coolant or restricted coolant flow. I removed the thermostat again, and for some reason stuck my finger down in the coolant in the thermostat fitting. I touched something and got it out - a rubber washer with a small hole in it. It was okay at low engine speed but when the flow increased, it rose with the flow and blocked the opening in the thermostat. I never figured out where it came from but I'll never forget how much trouble it caused me.


FINALLY: If you find out you have 'disappearing coolant', you know what that means - the engine has been run hot and it may need head gaskets.

 

Head gasket is last last resort..... i would make sure there's not a chunk of trash clogging the thermostat first. Maybe even pull the pump again..... i know.... pain in the ****, but it sounds like it could be junk to me. After that..... then get the heads checked