Smoke comes from the exhaust of my Ford Mondeo 1.6, 1997, petrol at
starting time when the engine is not warm enough, for example every
morning. It back to normal after about 2-4 minutes depending the weather.
Which part of the engine fails to work properly? Note that it is petrol
car. Any tips or advice on this problem appreciated.

Smoke, water vapor, or coolant? Is it something new, or has always been
there?
Water, in the form of steam, is produced in the combustion process. Until
the exhaust system warms up, it condenses there and creates that typical
white cloud out of the tailpipe in cold weather. This is perfectly normal.
If it's greenish (or orange, depending on the color of coolant you use) and
has that sickly sweet smell, your engine may have a blown head gasket or
worse, a crack in the cylinder block. Look for traces of that color inside
the tailpipe. Also check if the coolant level is dropping without any
visible leak.
Bluish smoke indicates burning oil due to worn valve guides or piston rings.
You may suspect that if the oil consumption is high and you don't see any
external leak. But usually the telltale smoke due to oil burning gets worse,
not better, when the engine warms up.

"ally131" <ali131m (AT) yahoo (DOT) co.uk> wrote