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SSI Insert revised (no index tag!): 22-Feb-2016
Article on The Internet Mini Encyclopædia |
This article was suggested by John Pechell a regular visitor to IME and describes smoke from the exhaust
ANY smoke or fumes from ANYWHERE else may be symptoms of mechanical binding, exhaust leakage or uncontrolled and potentially dangerous COMBUSTION (also known as FIRE) .. do not drive a car in this condition UNTIL the cause has been established and rectified... Exhaust smoke can be invisible and contains CARBON MONOXIDE... many people try to kill themselves by inhaling exhaust gases.. DO NOT DO IT ACCIDENTALLY....... IT CAN KILL;)
| Smoke Colour | Source | Cause | Relevant Cure |
| White/Light grey |
Water Vapour / Brake Fluid ( is this REALLY grey?) |
1) Blown/leaking head gasket 2) Engine running cold blowing off water in exhaust system Excess water/oil consumption/overheating? + oil and water mixing in sump and cooling system + "mayonaisse" in rocker cover = head gasket gone! 3) blown seals in brake servo, check for fluid in linking pipe |
1) Replace head gasket 2) check cooling system is running at high enough temperature 3) repair servo seals |
| Blue | Oil |
If almost continuous blue smoke = extremely worn engine/ blocked breathers / valve guides/ OR.... over filled carburettor dashpot!!!!! 1) If blue smoke MAINLY on acceleration= worn piston rings 2) If blue smoke MAINLY on start up and/or when throttle released (on overrun, his gives lots of manifold vacuum) = worn valve guides and/or valve guide oil seals and/or valve stems ALSO Engine may "run on" In extreme cases of valve stem/seal/guide wear a visible pool of oil is present in the dish of the pistons and car is difficult to start as oil reduces the octane of the inlet charge |
1) Rebuild engine 2) Replace worn guides/seals/valve stems. NB: Compression check values (psi) will NOT improve with small amount of oil down bore (take care.. little needed) if rings are NOT worn. |
| Black/Grey | Excess Fuelling | 1) Over rich carburation or choke engaged | 1) Adjust fuelling/ release choke mechanism |
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