People are keeping their cars and trucks longer due to the current economy. To get the most miles out of your car, you need to do routine maintenance on it and learn how to spot the signs of trouble. One sign of trouble is when smoke comes out of the exhaust system or from under the hood. The color of the smoke will give you some clues as to the nature of the problem.
White smoke coming from the tailpipe is normal when the car is cold. If it is constant, it is a sign that coolant is getting into one or more cylinders in the engine where it is burned. The white smoke is actually steam. Coolant leaking into a cylinder is most often caused by the vehicle overheating. The excessive heat will result in a cracked head or bad head gasket. To diagnose this you only have to check the level of coolant in the radiator or overflow bottle. If it is low, check the oil on either the oil fill cap or the dipstick. If it is a brown or milky color, there is coolant in it. If that is the case, it needs to be repaired immediately. If you continue to drive the vehicle, the engine will be severely damaged.
Blue or gray smoke is the result of oil leaking into one or more cylinders and burning with the fuel air mixture. This occurs more often in older cars or those with high mileage. Along with the smoke, you will also notice that the oil level in your car is always low, it tends to misfire, your gas mileage has dropped significantly and it has less power.
There are many things that can fail and thereby cause oil to seep into a cylinder. Those things include the PVC valve, piston rings, o-ring, head gasket, valve seals, valve guides and even a cracked head. To determine the cause and extend of the problem, a compression test should be done. For most people, that means taking the car to a repair shop. Unfortunately, the testing and repairs can cost several hundred dollars.
For a quick fix, you can try using a thicker weight oil or using an oil additive designed to reduce oil leaks. If you try this, you also need to either replace your spark plugs or at least clean the oil off of them.
Black smoke is a sign that there is too much gas or not enough air in the cylinders. The gas is not being completely burned. If you own an older car that has a carburetor, it might just be out of alignment or need the choke replaced. One of the most common causes of black smoke in modern cars and the easiest to fix is a dirty air filter. A dirty air filter reduces the amount of air in the cylinders. If the black smoke occurs when the car is accelerating, a bad valve stem seas is the likely cause. Other causes include faulty fuel pump, fuel injector, mass airflow sensor, throttle position sensor, engine coolant sensor, fuel pressure regulator, catalytic convertor, EGR valve or a vacuum leak. One way to check for a vacuum leak is to examine the hose to the PCV valve for signs of wear or cracks. If that is the case, replacing the hose should solve the problem. If not, you will have to take the car to a repair shop for an engine analysis and vacuum leak test.