Engine question

2000 Metro with just over 97K miles. Recently I have noticed a puff of smoke on startup in the mornings. I don't always notice it but have seen it several times. Also noticed that the oil consumption which has been pretty much zero has risen just a tiny amount so after about 3000 miles it is just below the upper mark - still very low.

Any ideas as to what this most likely could be and also how long before it degenerates into something more serious. I guess what I'm seeing is burning oil (white/blueish color).

Your valve seals are leaking oil past the valve and into the combustion chamber. It starts with a puff in the morning as oil seeps past the rotting seal over night, and then on start-up the trespassing lubricant is burned and tossed out as blueish smoke. If bad valve seals are left to degenerate you will start smoking when decelerating, as vacuum then is at it's highest, literally pulling oil from between the valve stem and the seal. So, the rate of degeneration is hard to say, some are exponential, some are linear, whatever you do, DON'T solve the problem by pouring that syrup crap in a can into your motor. Do it properly and replace the seals. It can be done either with the head on the motor or the head off the motor depending on the tools you have handy/are willing to aquire.

-mechanicmatt

OK thanks for the reply. Following a suggestion on this on the TS forum I removed and cleaned out the PCV valve and the hoses. Not sure if that had any effect but ithe smoking appears to have stopped. I will keep an eye on it though.

My factory manual shows the valve seals being replaced with the head off. Can it be done without removing the head

I did have a geo that was sending oil through the pcv and into the intake and was creating a pretty massive cloud at freeway speeds. I forgot about that - If cleaning out the pcv solved your problem forget about the seals. I have not done valve seals on geos with the head on the car, but in theory it can be done with compressed air and the right tools.