greetings, I just bought a 2008 super duty with a 6.4 motor. 102k. mostly highway miles. Main problem is, it uses about 1/2 gallon on coolant on a tank of gas. Can not find a visable leak. does not smell while running. today, after asking 2 or 3 mech's i'm about to sell the truck. they stated that the cylinder sleevs are prone to fail on this motor.

1. is this true? If not, what is a common failure item of the cooling system.
2. seems like the starter is not disengaging quickly after the switch is out of start position.

Also, what can I expect from this beast as far a common failure. the thing will surely pull the crap outa my boat

thanks, dale