theres no smoke out the exaust pipe no noise at all in the motor i timed the truck (i read somewhere that timing could cause this) i did a radiator flush.... during this i found a small vaccum leak fixed that.... glen is saying head gasket so my plan today will be tear down the motor after i do a compression check on all cylinders.... hopefully that tells me something....also buy a new radiator and all new hoses if that does not work im burning this truck in the driveway....just kidding....