Hi Zack, and welcome to the club..

This depends on the colour of the smoke on startup..
Blue, and it's oil related, probably the valve stem seals as you say.
White is water, and that could be a head gasket leak, or worse, a
cracked block..

The two symptoms may not be connected.

First have a look at the oil filler cap for any emulsion, a sure
sign of moisture in the engine, but not necessarily from the water..
blocked breather pipes can do the same.

check for any oily film in the radiator.

get a cylinder pressure test done..

If everything comes up OK... It would depend on how much water is
going.. start the engine and let it warm up.. the pressure may show
a leak better.

To recap.. blue smoke, valve seals, rings etc and you probably just
have a water leak somewhere.

White smoke, water is getting into the cylinders (steam)and you may
have a gasket or block problem.

Hope this helps, and keep us posted.

John



--- In mazda626uk@..., "zack_77_uk" <zack_77_uk@y...>
wrote:
> I have a 1988 626 coupe 2.0l 16v that has recently started to
smoke
> quite heavily at start up. Its also using water at the moment but
> with no apparent leaks. Could this possibly be related to a head
> gasket problem or would it more likely be the valve seals are worn
> out.
> Any help is greatly appreciated.. The engine has done 135 000
miles.
> Thanks ZACK