Okay, I will keep looking. If my road draft tube and tubing is clear, what else should I check? I get no smoke at all out the exhaust when the engine is cold or hot. Thats what kind of fooled me. I don't see a pcv valve. The PO said the truck was an original 76,000 mile engine. I don't know for sure though. It has been some kind of service truck might have spent hours running parked or who knows.
I have been around farm trucks enough to know its not the miles but the hours, too bad most old trucks did not have hour meters.
Found a sticker that says it had a valve job at 68,000 mi. Of course that was in 94. The sticker also says to send the S-0-S sample in promptly. I know that is oil monitoring for a large fleet operation. As far as other history I don't know when it left the fleet and what happened to it after that. Thanks for the replies and help.
