Hi, i've got a 911 Cs4 o2 plate and in the past week its smoked like a train on start up, worst when its been left over nite. it smokes for about 20s then clears theres no smoke when under load or at idle just when 1st started!!???? i,ve checked that it hasent been overfilled of oil as it was recently serviced that th oil level is fine. Anyone come across this before or have any idea what could be causeing this????????? thanks in advance.
smoke on start up!
- Thread starter 944rob
- Start date
The inherrant nature of the horzontally opposed flat six engine allows for oil to settle in the bores, as opposed the 'normal' vertical engine which drains oil to the sump.
Oils therefore rests on the lower side of the cylinder liners (bores) and will seep past the piston rings - hence on start up it can / will smoke to a lesser of greater extent. And that depends on a number of factors - one on which you have highlighted and another is wear between the piston rings and the bore.
MIne does it now and again but not all the time. Yours appears excessive and could indicate a possible problem.
A compression test should help to decide the amount of wear, if any, you have.
Oils therefore rests on the lower side of the cylinder liners (bores) and will seep past the piston rings - hence on start up it can / will smoke to a lesser of greater extent. And that depends on a number of factors - one on which you have highlighted and another is wear between the piston rings and the bore.
MIne does it now and again but not all the time. Yours appears excessive and could indicate a possible problem.
A compression test should help to decide the amount of wear, if any, you have.
Blue smoke or white smoke? If it's white, then it could be the air/oil separator. A good check is to remove the inlet hose to the throttle body, open the butterfly, and look inside for oil residue.
i have a look under the hood at the inlet pipes and the pipe going to the right hand bank has signs of oil seapage were the pipe joins the inlet manifold and the j-clips/ pipe are wet with oil, were as the left hand pipe is dry, would this be caused by the air/oil separator??? The smoke is white'ish and it smokes from both pipes when its started.
I'm not sure which pipes you refer to. What I meant was to take off the inlet tube to the throttle body (3 hose clips) and look inside there:
Sorry - now I get it. Sounds suspect to me, and I would check inside if you can. What happens is that the air/oil separator splits internally, and the oil mist is drawn into the the inlet tract, and hence into the engine, causing the smoke. On the way through, the oil sticks to the walls of the TB, so if it's there, it's probabbly the AOS causing it.
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