Smokey Exhaust - Page 2 - Ford Forums

MYF6 · 01-25-2005, 21:27

If its blue smoke, not black, then get it checked out asap - compression test will be enough to check if its something to be concerned about, or not. When you were following and saw the smoke did it smell oily?

madmelon · 01-26-2005, 03:32

revving a car when its cold will always produce a little blue smoke from burning oil. About the only time it wouldn't is if the engine had very very few kilometres on it and the rings were still very tight in the bores. There is nothing you can do about it either. Get it checked, but they will likely say nothing wrong. Its for this reason that your not supposed to work an engine hard when its cold.
Everything changes size at it is heated. about 99% of all things (including what engiens are made of) expand when they are heated. Contrary to popular belief, a hole in a piece of metal will also expand when the metal is heated. Now that means the bores will get bigger when the car warms up, but because the aluminium pistons and steel rings expand MORE than cast iron, the tiny gaps around the pistons close up when the engine gets warm. Although i'm not certain of the material the valve stem seals are made from, i would be willing to bet that the same process happens at the valve stems.
It is for these reasons that heads crack when you overheat a car too- the head expands with nowhere to go, so it cracks. This is also why an engine will stop when it overheats- the pistons have expanded too much in the bores.
I'm willing to bet every car blows smoke when its cold (some worse than others) but it shouldn't be too much if you're not giving it some stick...if you are tho, you can go thru 5 litres of oil in about 2-3 weeks (sum of my mates don't care if the car is cold...)

madmelon · 01-26-2005, 04:59

Just thinking- its a turbo car, so perhaps there is a leaking seal somewhere in the turbo. It wouldn't have to be much- the smallest bit of oil makes a fair bit of smoke.

Xtreme F6 · 01-26-2005, 05:33

Quote:

Originally Posted by CDAA

Wouldn't that be black smoke rather than blue? Lets hope your right anyway.

exactly on the money CDAA. BLack would indicate fuel blue would indicate... HALP! but if it goes after the first throttle off i would be inclined to say seals and or guides