HI--ABOUT SIX WEEKS AGO MY TRUCK WAS MISSING AFTER START UP,
THEN CLEARED UP. LAST WEEK OUT OF THE BLUE THE HEAT GAUGE GOES TO "H",TRIPS THE ALARM THEN GOES DOWN TO NORMAL. I CHANGED THE THERMOSTAT. IT DID IT 3 MORE TIMES. TOOK IT TO THE SHOP,THEY PULLED THE CODES--P0325 KNOCK SENS,P1285 CY HEAD TEMP,P1299 CY HEAD TEMP. CHECKED THE PUMP, CHANGED THE CAP, DID A DYE TEST AND SHOWED CARBON MONOXIDE IN COOLANT. PUT IN A CAN OF KSEAL. I DIDNT MAKE IT HOME. HES TELLIN ME HEAD GASKET OR CRACKED HEAD.------DO YOU AGREE WITH THIS? AND DOES HE HAVE TO PULL THE MOTOR? HE SAYS SO? THANKS

 

Thanks for yelling (CAPS) at us
From your description sounds like you do have a problem. I would never go ahead with big job without getting a second opinion. This forum can offer you a guidance, but we can not turn the bolts via our computers. Good luck.