Just "inherited" a OK shape '81 - 300SD. Runs pretty good,not great. Went in today to get it registered and it did not pass emissions. Guy there said that the 3rd cylinder has a oil leak? Is this serious? He made it sound like it was really dangerous. Or is it simply that this particular glow plug seal is bad. I am not the diesel master, ..but....aren't diesels supposed to have oil in the cylinders? Mixes with fuel? Any help will be appreciated. Hate to spend any real money on it. I'm pretty handy and can typically tackle any fix it project. Gets great gas (diesel) mileage, and seems to run good. Makes a great extra car for a family of 3 drivers (and up till now only 2 cars)

Thanks

Larry