Hi all. Have a punto 1.2 2003. sometimes some white smoke upon starting, and rough idle, but both only some days. It can be fine for a few days, then have the smoke and rough idle for a day or two, All seems OK when running at speed.. but can run rough anytime at idle, ie traffic lights etc. Water and oil levels are fine. valves have had new seals from Garage. Garage are mystified by it and not come across this before and they think there is a residue of oil for some reason.. Any help appreciated.

No Mayo?
No Water Loss?

White smoke is either water been boiled off

or

You've got a super cold intake, cold air heated = Steam

But rough idle - could be water in cylinders making it misfire?

Have the Cooling System pressure tested - it should hold pressure spot on
if there is any drop - look for leaks in the cabin too
If no leaks found - but you find on start up its running rough

Then compression test it - it'll confirm the suspect HG

Ziggy

Ziggy

Hi. Thanks for the advice, but it has been pressure tested and all is OK. Two garages have been mystified by this, and they have been asking other mechanics for any advice. When it decides to kick out the white smoke, it is thick, and lots of it, but only for a couple of seconds, then clears and after a few more seconds, it usually runs fine, just occasional missing at traffic lights, roundabouts etc, but not too often.

could be a seal on one of the valves and would explain why it only happens some times when you start it dependin on the position of the valves when the engine is turned off dripping oil into the cylinder and white smoke when you start it as it burns out the oil and could be happenin when your at traffic cause your engine is only ticking over and not running quick enough to burn out the oil

it must have a fizzure in the head somewhere
as ziggy says it needs a pressure tester on it but this time leave it up at 14lbs and bring engine up to operating temperature watching the gauge
plus connect a vacuum gauge same time watching that too and listening for little misses

Had new seals on the valves, but it really seems like this is the problem, as flyrod says. System has been pressure tested and all is more than OK, Very good reading. If valve seals have been replaced, but still the problem is there anything that I can do without replacing the top end ? Just seem to keep spending money, without solving the problem....

Thanks to all of you for your replies and advice...

White = Water
Oil = Blue smoke

The valve seals are oil surrounded, so if they were leaking it'd be leaking oil into the cylinder and that'd be your problem with Blue smoke

White smoke is water, your somehow leaking water into the cylinders when hot?
You need to probably do a hot cooling system test to confirm ifs a leak when hot

Ziggy