You can diagnose a variety of car problems judging by color of the smoke emitting from the exhaust tailpipe.
Blue smoke: When engine oil enters into the engine combustion chamber and burns along with fuel and air mixture, you can see blue smoke coming out of the exhaust tailpipe. Call your mechanic to check the leak and correct the problem.
Black smoke: Black smoke is a result of an excessively rich mixture of air and fuel entering into the cylinder area. The proportion of fuel is more in the air to fuel ratio. This fuel rich mixture does not burn completely in the combustion chamber and produces black smoke coming out of the tailpipe, thus affecting engine performance and fuel economy. Although rich mixture is necessary for engine start-up, black smoke is indication for a faulty injection system or sensors in the engine computer. Get your car tested for emission and call your mechanic for engine tune-up.
White smoke: The white smoke coming from the exhaust tailpipe is actually the steam, which indicates that water or antifreeze is being burned along with the fuel and air mixture in the engine. You may also judge the problem, if you have to add water and antifreeze more frequently than normal. Water or antifreeze if mixed with the engine oil entering into the engine cylinder can damage the engine seriously. Have your mechanic check for leaks and fix the problem immediately.
Always check the pavement or floor for a spot or puddle of fluid beneath your car when parked overnight. If you develop this habit of checking for new leaks under the car, you can stay ahead of many problems before they become severe. You can identify the type of leak by the color of the fluid accumulated on the spot of the leak.
Oily and Black or dark: The leaking fluid is most likely the engine oil. Check for the oil level by removing the dipstick and measuring the fluid level. Refill the oil according to the mark on the dipstick and observe the level for a next few days. If you find the oil level dropped and spot or the puddle again, its time to get the leak inspected by your mechanic.
Oily and Red: Most likely to be the transmission fluid. Check the transmission fluid level, refill it and observe for the next few days. If you find that the level has dropped, get it checked by your mechanic to avoid damage to the transmission.
Green or Yellow: Likely to be the coolant leak. Get the leak identified and fixed by your mechanic.
Clear Fluid: Most likely drain water from the car’s air conditioning unit or windshield washer fluid. You may have to touch and feel the fluid or smell it to determine if it is water.
Clear and oily: It is most likely to be brake fluid, which is a more serious type of leak. Get the leak identified and repaired by your mechanic to avoid brake failure.