In a properly running car, the exhaust will usually be light and practically colorless. You may not even be able to notice the exhaust. However, if there's something wrong somewhere, one of the first indicators will be a change in the nature of the exhaust. The exhaust can become thicker and also have various colors all of which point to specific issues within the car.
In some cases, a heavier exhaust is to be expected in hard running conditions such as when the car is being started up in the morning. In most other cases, a colored and thick exhaust will mean something isn't right.
Black or Gray Smoke
Black or gray smoke is usually produced when the fuel is not being properly combusted in the engine. Several factors can lead to this including:
Your air filter is clogged
The timing of the ignition system is off
There is a blocked manifold
There's a problem with the fuel injection system
Smoke with a slightly blue hue is usually the result of engine oil being burned. If engine oil is being combusted, this could be because:
The oil is leaking into the combustion chamber
There is some wearing of the cylinders, piston rings or valves
White smoke is usually the result of water or coolant being vaporized in the combustion chamber. This could mean:
There is a leak in the head gasket
The engine block or cylinder head is cracked
When it comes to white smoke, the only real concern is when the smoke is thick. Light white smoke doesn't always indicate a problem. It's also possible to get water vapor or smoke coming out of the exhaust when the engine is too cold. In case the temperatures outside are low, this is to be expected. If smoke is still noticeable once the engine is warm, there is another issue to look at.
Diesel Vs. Gasoline Engines
Although the reasons for particular smoke colors are more or less the same whether it's a diesel or petrol car, the underlying reason might be different. This is because these two types of engines have different components. For example, injection systems are usually associated with diesel engines.
Regardless of what type of engine your car uses, you'll probably need professional auto repair to deal with most of these issues. Despite the fact that car is running, not getting the damage fixed will be detrimental to the car in the long run. Contact a company like Hillis 66 Service for more information and assistance.