Modern vehicles shouldn't be putting out smoke from exhaust pipes when they're running properly. When you notice smoke coming from your vehicle, it doesn't necessarily signal a serious problem, but is typically something you want to get checked out. You can start by simply identifying the color of the smoke. White smoke comes from water mixing with the exhaust or combustion cycle. Blue smoke means there's oil mixed in. Black smoke means you're "running rich", or there's too much fuel in the combustion cycle. Here's a closer look at what each color of smoke may mean for your vehicle.
If you notice white smoke as soon as you start your engine, you'll want to let the car warm up to gain more knowledge about the potential problem. If you allow your vehicle's engine to warm up and the smoke stops, it was likely just steam. This is normal and will go away as you drive. If white smoke remains, you'll want to stop and check your coolant level. If it's low, you may have a serious problem, but there's more testing to do. Fill the reservoir, then drive around normally for a day or so. Then, check your coolant level again. If it's not low, you've got no problem. However, if the levels have dropped significantly again, your cylinder head gasket is faulty and needs to be replaced.
Finding the faulty component when there's oil in your combustion cycle is a little trickier, but still workable for just about any driver. Your first option is to replace the PCV valve, which allows gases to move from the crankcase of an internal combustion engine to the intake manifold. Replacing it is typically a quick job. When it's done, check to see if blue smoke is still present. If not, you've fixed the problem. If blue smoke is still coming from your tailpipe, your next step depends on whether or not your car is turbocharged. For a turbocharged car, you can take off the intake tube and check it for oil. Oil in this tube signals that oil seals have failed and the turbo needs to be replaced. If the car isn't turbocharged, or there's no oil in the intake tube, the problem is likely to be with the engine's oil seals. A leakdown test and compression check performed by your mechanic will reveal if the problem is in the valve guide seals or piston rings.
For black smoke pouring out of your exhaust pipe, it typically warrants at least a check and tune-up from your auto shop. Much like the investigation process for white smoke, you'll want to let your car warm up before panicking too much. If the black smokes stops once your car gets warm, there's probably no major issues, but again, it's a good idea to have it checked out. If the smoke continues, changing the spark plugs could fix it. If it's not the spark plugs, the problem can be found somewhere in the fuel system. It could specifically be an issue with the Mass Air Flow sensor, fuel injectors, fuel return line or fuel pressure regulator.
If you notice smoke coming from your BMW, Mercedes or Hummer H1, we're here to help. Bring your vehicle to the experts at Benzin Motor Works, and we'll diagnose the problem and make the needed repairs quickly. Call us today at 918-728-6081.