Know your smoke

[trevd01]

There is often lots of questions about what different colours smoke mean when they are coming out of a Bongo's exhaust. In fact there are current topics here right now.

I came across this today, and it seems a pretty good summary of what many people have posted here over the months.

• White smoke: White smoke is caused by water and or antifreeze entering the cylinder, and the engine trying to burn it with the fuel. The white smoke is steam…
• Blue Smoke: Blue smoke is caused by engine oil entering the cylinder area and being burned along with the fuel air mixture. As with the white smoke, just a small drop of oil leaking into the cylinder can produce blue smoke out the tailpipe…
• Black Smoke: Black smoke is caused by excess fuel that has entered the cylinder area and cannot be burned completely. Another term for excess fuel is “running rich.” Poor fuel mileage is also a common complaint when black smoke comes out of the tailpipe.

From http://www.trustmymechanic.com (which you may have spotted from the wording is a US site)

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From http://www.trustmymechanic.com (which you may have spotted from the wording is a US site)

Which almost certainly means that all that relates only to petrol engines.

and for petrol engines all that is true.

However diesels can produce white smoke that is 100% smoke - no water vapour whatsoever.

It is a symptom of retarded injector timing which does not allow enough time for all the injected diesel to burn and thus it is exhausted as fuel vapour which is white.