Oil consumption puzzle

There are two common reasons- valve seals and rings. Usually it has been my experience that white smoke on startup is more commonly valve seals than rings. Rings smoke a lot on deceleration.

Agree with Don. Smoke from valve seals usually disappears after the engine is running (small amounts burned or converted in the catalytic converter).

OP almost certainly will have a little ring or cylinder wear after those miles.

White material on the spark plug is the remnant of oil additives which have burned on the plug.

I agree with both previous posts. At that kind of mileage any engine will be showing some wear, particularly a smaller more heavily stressed engine like your Renault.

Since valve seals are quicker and easier to replace than rings (which require a complete overhaul), you might want to do some further diagnosis. Worn rings will manifest themselves by showing a much larger difference between "wet" and "dry" compression test readings- so if your compression goes way up after squirting a shot of oil in the cylinder, then its probably rings. Another much quicker test is this- find a long downhill stretch of road. Drive down it while coasting, preferably in a lower gear so that the engine is being revved up and is providing a lot of engine braking. If you get wafts of smoke out the tailpipe while doing that, or if you get a big puff of smoke when you step on the gas after coasting, its almost certainly rings. Valves will smoke more on startup, or when revving up for the first time after extended idling, such as at a traffic light.

If you see the smoke only when first started, and not on acceleration, it is most likely valve guide seals. But you will not really know for sure until you open the engine.

Not without pulling the valve covers, but I would first look at the valve guide seals before checking anything else.

It's burned oil. This at least assures you that your oil is burning rather than leaking out somewhere. And it means you know which cylinders have the problem.

--scott

Worn rings will manifest themselves by showing a much larger

If the compression rings are bad, this is quite true. If the oil rings are bad, this test is meaningless, as the rings are already wet with oil. HTH, Ben

White smoke is Anti-freeze. Blue is from oil, which would be valve seals, guides, rings, etc.