so here is the new problem.

Just replaced the head gaskets, Thermostat and heater control vale.


The truck is no longer over heating, but now it wont heat up correctly. It heats up to the appropriate level while it is idling, then about a min later it drops to just about cold. While running down the road it is running it runs colder than it should also. So Im wondering what could be causing this. Keep in mind it has a brand new thermostat. oh and yes I got the heads milled and replaced both head gaskets.

 

The only thing that would allow for over cooling is the stat.

Rich

 

mine does the same thing...even in the summer, the only time it would even get near mid way on the temp gauge was if you let it idle a bit...in the winter, i dont think it even gets above the cold mark.

 

yea that is wierd, basically the same as what mine is doing... not very much heat out of the heater either.

ITS NOT THE THERMOSTAT lol

replaced the thermostat, temp sensor, heater valve, head gaskets, Flushed the system a couple times. fan clutch prolly has 15k miles on it.

anyone got any ideas???

 

Are you sure you installed the thermostat correctly??

I have bought several bad thermostats in sucession.

Try removing the thermostat and putting it in a soup can of water and held off the sides and bottom of the can with wires. Use a good bulb thermometer or such that will go past boiling, at least to 300deg.F. Take a torch and heat the water and when the temp shows what the thermostat is rated at it should start opening. If sooner or later the thermostat is bad. Replace it.

edit: yeah, you can use the stove but I am shop oriented and seldom think house. I guess it's all the years in trk shops and machine shops.

 

I second the idea of testing the new thermostat. It could stick open. I would use the kitchen stove instead, for better control.
...Terry

 

hmm thats a good idea for testing it. yea I figured beacuse i blew the head gasket from overheating it might had killed the brand new thermostat i put in so i replaced it with another new one from a different store of a different brand. typically when you have several bad ones in a row its because the batch produced was bad. I might give that test a shot.

 

the themostat most likely needs replaced you said it doesn't over heat now and cools down when u drive it must be opening to early and is stuck open.