Hey guys, I was having a problem with my truck overheating so I thought It might be the thermostat. I boiled it to see if it would open and everything checked out. Confused, I decided to get a new thermostat anyways, but it didn't solve the over heating problem. So for the last couple weeks I've been driving around with no thermostat and haven't had any problems. Any Ideas guys?

First, search this forum and others for overheating or similar search criteria. See what you find. This is a very common problem.

Overheating can be caused by:

Blown head gasket.
Bad water pump.
Bad radiator fan.
Clogged radiator. Check the radiator fins for obstructions (bugs, leaves)
Radiator cap.
Collapsed hoses in the cooling system.
Lack of coolant and/or oil.

Do a compression check.
Look to see if you have coolant in the oil.
Look at the spark plugs to see if they are coolant fouled.

At what temperature did your old thermostat open?
Running without a thermostat can also cause overheating since the coolant can't cool off in the radiator.

I don't remember what the temperture was but it was the correct one according to the manual I have. Those are all good suggestions I'll have to check them out, especially the head gasket/compression thing.

I think the problem is the fan clutch, I idled the car for 5 minutes or so and turned it off and it kept spinning. Sound right guys?

Did you check out everything else first?