thermostat symptoms?

[e34_spangler]

Can I thermostat cause the engine to run really cold and push coolant out the overflow?

[jlevie]

A bad thermostat that is stuck open will cause the engine to run cold. But fluid being pushed out of the overflow will be from a head gasket leak that is pumping air into the system and causing the cap to lift to vent the excess pressure or a bad cap.

[e34_spangler]

A bad thermostat that is stuck open will cause the engine to run cold. But fluid being pushed out of the overflow will be from a head gasket leak that is pumping air into the system and causing the cap to lift to vent the excess pressure or a bad cap.

So your saying a head gasket and cap are only causes of coolant coming oiy the overflow

[jlevie]

Well, that or an overheat and boiling the coolant, which will damage the head gasket.