Black, Blue and White Smoke From Exhaust. What It Means.

2 years ago
23

In this video I go over three different types of exhaust smoke that a vehicle may produce and what causes them. These are typically black smoke, blue smoke and white smoke. Black smoke is usually made by an overly "rich" condition. In an overly rich condition too much fuel is present in the air fuel mixture. This produces a black smoke that smell like burnt raw fuel. Blue smoke is caused by oil being burned in the combustion chamber or in the exhaust system. When oil either in the engine or the exhaust system it produces a very light blue colored smoke. White smoke, under conditions where there is a problem, is typically caused by coolant intrusion into the combustion chamber of the engine. When the coolant burns it produces steam that comes out of the exhaust as a white smoke.

Some of you may be wondering about air fuel ratio. The ideal air fuel ratio is 14.7:1. That's 14.7 parts of air to 1 part of fuel. So when you get anything greater than 1 part of fuel to 14.7 parts of air then you have a rich condition. For instance if you have a ratio of 14.7:2, 2 being 2 parts of fuel, then your vehicle is running rich. Conversely if you have a ratio of 14.7: .75 then your vehicle is running lean, not enough fuel to air.

Here is a helpful link to help you understand more about air fuel ratio:
https://en.wikipedia.org/wiki/Stoichiometry

Note: As mentioned in the video, this is a very superficial and generic video. It does not cover every scenario and situation where smoke is produced by a vehicle. There may be somethings that can produce smoke and smokes of differing colors that where not mentioned. But, in my experience, these are the most common smokes that can be produced by a vehicle and these are the most common causes of these smokes. This video is based off of my experience and is not a full and comprehensive explanation. Further more there are situations where excessive fuel can cause white smoke. The information in this video doesn't apply to every situation. There can be variations and variations I'm not aware of.

Note: Rich conditions that cause black smoke can also be caused by an air restriction. If not enough air is being introduced into the combustion chamber then an overly rich condition can result. Also, I don't mean to throw you off but white smoke can also be caused by too much fuel, excessive amounts, getting into the combustion chamber.

DISCLAIMER
Barbour's Auto Help is not responsible for any damage or personal injury incurred in the process of performing any auto repairs done by you the viewer. Automotive repair is extremely dangerous. Repair your vehicle at your own risk. It is the viewers responsibility to verify all information and procedures as outlined in YOUR REPAIR MANUAL AND OWNERS MANUAL FOR YOUR VEHICLE. Owning and using a repair manual suited for your vehicle is essential for correctly and safely performing ANY repair to your vehicle. Always wear safety glasses, protective gloves and heed all instructions for use applicable to any piece of equipment you may use. Due to circumstances out of the control of Barbour's Auto Help, Barbour's Auto Help makes no guarantee that by the use of the information given in this video a quality repair will be made. Barbour's Auto Help makes no guarantee that the information provided is totally complete, synchronized and accurate. Verify everything using an appropriate repair manual. Verify everything with your own research.

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