My friend has a 89 f 150 w the 351w efi, they over heated it and tried to change the t stat and broke one of the bolts. the intake ended up being changed because they destroyed the bolt holes trying to fix it. The problem now is it starts great when cold ,but after driving it for a hr it starts real hard. My question is, is it possible they did damage to the motor, because it does have a slight knock(in the valve train area),and if you remove the hose from the oil fill tube it smokes like crazy like coolant. but it is very faint?? they said it is a new motor ,but there are to many signs of being a old motor. any thought would be great.
Do a dry/wet compression test to see if the block is still OK.
Of course it should not smoke who knows what clowns like that did to anything if they're breaking pieces off. But do my video how to tell if your head gasket is blown Scotty. Then you'll know if it needs a head gasket
Doc and Scotty thanks .
