Would you rebuild?....

I would also check the heater core. Mine is an 07 Pete with a C15 and it fogged the windshield at times. Also coolant smell and no excessive blow by. It was the heater core in that particular instance. Hope this helps.

 

Could be a bad radiator cap not holding pressure and venting out of the overflow tube.

 

If it matters, I just did an overhaul on my c-15 cat. However it had well over 1.1 million on it. Go to a mechanic if before deciding on overhaul. Like others have stated it could be a smaller issue. Typically at 700k miles I think it's too early for an overhaul; but I don't know how that truck was run or if it was taken care of like it was supposed to.

 

Look at your radiator pipes, make sure all the hose clamps are tight and replace all your rubber hoses on the ends of the pipes. I just replaced my upper and lower pipes with all new rubber hose ends and clamps. Was loosing a little coolant because of them and now its not leaking.

 

Well I will tell you I felt the same way about my last truck which was an International with a Detroit S60, always told myself it was a throw away truck and after rebuilding and replacing everything from the front to the back it developed a coolant leak, which happened to be a warped head, that was probably the only thing that had'nt been replaced, that was the final straw and the excuse I needed to get rid of it, dirt cheap considering all the money I put into it, needless to say 5 years later I still see that truck being operated by the person who bought it, if I had to do it again I would have kept it..