chrishalling

A Few Months Ago, I Was Driving To Work When My Heater Valve Decided To Fall Apart. There Was Coolant And Water From My Cooling System Making Thick White Smoke Until I Was Able To Pull Off The Road And Find The Problem. I Changed The Valve And Refilled My Coolant Reservoir. My Truck Ran Within The Normal Operating Temperatures For About A Month Then It Started Over Heating. I Saw The Coolant Level Was Low And Topped It Off. This Has Been An Ongoing Occurance. I Have Looked At My Chiltons Book And Filled It Then Let It Warm Up And Make Sure To Top It Off. There Is No Cap, The Reservoir Is Part Of The Closed System So Any Air Should Escape The System But The Coolant Should Recondense And Reenter The System. I Do Not Know What Else To Do. There Are No Signs Of Leaks Under The Engine And No Signs It Is In The Oil, So I Cannot Think Of Anything Else To Try. Any Advice Would Be Great.