Our trusty '88 wagon (with 233K on it) has started to smoke (white) when idling. At first I thought it was the condensation burning off. The car has always dripped clear water droplets from the tail pipe but now even on a warm day and after several mins of driving I still notice the white smoke. It does disappear when the engine is rev'd.

I seem to remember this as a tell tale sign of a valve job, do you guys agree ?