Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show


My '85 Mercedes Diesel has just started smoking badly from the exhaust. This not at starting but after the engine warms up and is worst at driving around town. Rings? Valve guides? Valves?

It runs fine. No terrible new noises. People are dropping back a good 50 yds!

You must determine whether it is blue smoke which would be oil or white smoke which would be fuel. If blue smoke and smells like burned oil, I would suspect a broken ring with major repairs ahead. Valve seals would more likely do it on start up and valves wouldn’t do it. If it is white or black smoke, then you’ve got a fuel problem and the injector pump will need repair.

If it’s BLACK smoke, you are running an overly rich fuel/air mixture, possiobly caused by a leaking injector. White smoke could be a coolant leak and blue smoke means the engine is using oil.

In all cases, a good diesel mechanic will be able to figure it out quickly. A leaking injector would be the least expensive to fix.

Good luck, and please let us know how you made out.