I'm having slight complications with the cooling system in my '90 Formula 350. Long story short, though I had a leak but that wasn't the case. Figures the cooling system was only filled to about 1/3 or 1/2 capacity. Added coolant, drove, temp gauge worked fine (dead cold engine temp at 110). Now the temp guage is off waaaaaaaaaaaay past the 240 degree mark even when dead cold. It'll occasionally show the actual tem before jumping back to past 240, in addition, I have to add some coolant every day. Like I said no leak but the coolant is going somewhere and it's not the overflow tank. Need help really bad, it will be greatly appreciated.

 

when the engine is hot, try putting your hands near the coolent hoses and thermostat housing..

i had that prob, for a couple weeks until i realized that the steam was excaping from my thermostat housing not sealing correctly...

the water never leaked out.. but over the peroid of 3 weeks or so, it would get low for no reason..


resurfacing the housing and a new gasket fixed my prob...


see if you can find a leak, either water or steam.. dont forget to check the heater core.

 

Are U sure U are getting the system all the way full?

Run car with cap off until stat opens (u will see level go down or at least start flowing through cap opening) add water or coolant until it is full. When adding cold water or coolant the cold can make stat close again. When U think it IS full put cap back on and take it fo fa ride. Let it sit long enoigh and remove cap and add as needed.

Also sounds like temp meter could be malfunctioning. Factory or aftermarket?