I looked at a '96 FLD120 today. 3406, 5EK. It has seen little use for last 7 years, clock shows 420K, overall condition looks like could be correct. Engine started good and sounded good from the start. No smoke on snap throttle. I took it for a drive, rolls coal hard for a short bit on acceleration. I kinda figured that as some previous owner had a smoke mirror on driver's side. Oil was sludgy on initial check. After test drive there was quite a bit of moisture in the vapor coming out of the oil filler tube. My first thought is lower sleeve o-rings are shot. Any other thoughts? Cheap fix, or new sleeves?
Not typically with anything that has the CAT logo. Once into at 28 years old-it will be at least a inframe as far as labor costs, wouldn't know about parts till disassembled. How much vapor at breather tube? How clean and color of smoke on start up? It really shouldn't smoke that hard on acceleration. I think this is one that needs oil tested.
Exhaust manifold gasket was known to break pieces and suck into the turbo it has an exhaust leak around the manifold may need a turbo.
Vapor=turbo?
When you drove it did it get up to temp?