My 1987 Peugeot 205 CTi is a project car that hadn’t run in many years. It runs now, but it smokes. There’s oil on the plugs, on the inside. My mechanic says: probably piston rings, better swap the engine block. What says you?

We’ve already replaced the valve stem seals, which were a likely cause. However, they were not and it still smokes. In a compression test one of the cylinders has 10% lower compression than the others.

I’ve read stories about throwing certain fluids in the oil or directly in the cylinders to loosen the piston rings. Worth a shot?

Besides smoke there’s also a sound coming from the engine when accelerating that sounds like a bad bearing. It seems to be getting worse, but that might also be psychological because we fixed the exhaust, which made the car more quiet.

For those that don’t know: it’s a fuel injected engine without cat.

On the day I bought it, last year.