Smoke coming out of your exhaust is relatively normal. After all, combustion engines produce gases, which have to go somewhere. In general, the smoke coming out of the exhaust is barely visible, but if it is colored, you should ask yourself questions. This may be a sign of engine damage that is coming soon. In this guide, you will learn everything you need to know about exhaust smoke.
Operation of the combustion engine
All types of combustion engine work the same way: Fuel is consumed under high pressure . This leads to an explosion, which sets the piston in motion. This movement starts the engine mechanism and powers the powertrain. Whether it is a four-stroke, two-stroke gasoline engine, diesel engine or rotary engine, the basic way of operation does not change.
What goes into the combustion chamber?
exhaust warning colorFor four-stroke petrol engines and diesel engines, only the mixture of fuel and water reaches the engine. It is then consumed and allows the purification of the exhaust gases. In two-stroke gasoline engines, such as those found in mopeds, chainsaws or lawnmowers, oil is also present in the combustion chamber. This is the reason why mopeds always leave a plume of blue smoke behind them.
It’s better not to pretend that nothing has happened. Large diesel boats also have a two-stroke petrol engine, but play no role in road traffic. Old fighter planes were also water injected. Sudden evaporation of water was expected to increase performance in the short term, which worked well. For vehicle engines, this technique has never been implemented.
In summary, here’s what you need to know: air and fuel can enter the combustion chamber. These are composed of vaporized gasoline, propelled gas or diesel. Nothing else should enter the combustion chamber. Diesel cleaning systems also use the combustion chamber for the combustion of rust particles. This happens via the EGR valve in the intake wing, was constructively planned, and has no impact on the color of the exhaust gases.
The colors of the exhaust gases that warn
The exhaust gases must be colorless or have a light gray or white color. If the smoke is more visible than that, take it as a warning. The typical colors of a smoke are:
– White : water is present in the exhaust gases
– Black : the engine consumes grease
– Blue : the oil can reach the combustion chamber
White smoke caused by humidity
white smoke due to humidity White smoke always reveals a lot of traces of humidity . Before getting a fright, it is better to look into it. In winter appear large white clouds of steam and smoke. This happens when a car in a warm state is parked in the cold for several hours. The exhaust works by cooling the condensation of ambient air. It is totaly normal. One liter of water produces 1650 liters of white vapour, so starting cold can be justified: only a few centiliters of water are needed to form the desired vapour . The hot smoke from the exhaust quickly dries out the exhaust system so the white vapor can quickly disappear.
If the throttle color stays white all the time while driving, you should take a look. The only way to get water into the combustion chamber when the engine is hot is through the cooling system. The cooling system continuously injects coolant into the engine. This is made up of water and antifreeze and corrosion protection. The interface on which the cooling system and the combustion chamber are tightly laid is the cylinder head gasket. When it melts, water can enter the combustion chamber. But, in this case, engine pressure can also enter the cooling system. It can be seen clearly:
- Switch off the motor
- Pressure test in the pipe
- Allow the motor to cool
- Carefully open the covers of the compensating tank or cooler
- Refill the refrigerant
- Let the engine run with the compensating tank open or chiller
- Check water behavior
the typical damage around gasesA hot motor always poses a risk of burns . This is why you should never work with a hot, running engine. With the engine off, lightly squeeze the large hoses of the cooler system. If you perceive a clear resistance, it is already a great indication of the presence of pressure in the cooling waters. The pressure must be released, therefore the motor must be allowed to cool down. The lids must be opened in two steps: A quarter turn releases excess pressure. Then, when you no longer hear any hissing, you can remove the caps entirely.
When the refrigerant is recharged, let the engine run. Then look in the compensation tank or cooler. If bubbles form, the cylinder head gasket is probably damaged.