Forget about the thick black smoke for a while. Anytime you see different colored exhaust fumes coming off the exhaust pipe, know that your Porsche is drawing your attention to something vital within the engine. It does not matter whether or not the vehicle flashes warning lights or not. Smoke coming off your exhaust system in huge volumes is always a sign that something is terribly wrong. Note that sometimes, the exhaust will first emit gray, blue or white smoke before things worsen and black smoke comes out. Read on to learn more.
Blue smoke is a sure sign that your Porsche engine is burning oil. This happens when piston rings and valve guide seals begin to wear out. Oil therefore leaks from where it should be reducing friction by lubricating moving parts. The leak is more often than not from the piston rings and valve guide seals all the way to the combustion chamber where it eventually burns up with fuel. Another simple reason why you could be seeing blue smoke may have everything to do with a faulty blower. However, this problem only affects turbocharged models.
Inspect your Porsche’s engine oil on a regular basis as you watch for any abnormal consumption issues. Then replace valve guide seals and piston rings as soon as you notice they have worn out. If for some reason there is nothing wrong with the piston ring and the valve guide seals, top up the oil regularly. Remember that apart from environmental pollution, burning oil can easily cause rough starts. This eventually ruins sparks plugs which can be costly to repair.
Just like blue smoke, gray smoke can mean that there is a problem with the turbo charger or the car is burning oil. The best solution here is to take the exact same precautions as explained above under blue some. You should also check for excessive oil consumption.
Start off your inspection at the Positive Crankcase Ventilation, which could be stuck. This will force pressure to build and oil to leak. Fortunately, PVC valves are easy to repair. They are also easy to replace. In severe cases, gray smoke could be a sign that your Porsche’s automatic transmission fluid is burning up inside the engine. The main culprit in this situation would be the transmission vacuum modulator. It may lead transmission fluid the wrong way and have it sucked into the engine where it will burn up with fuel. The best you can do here is to repair or replace the transmission vacuum modulator.
The component you should inspect once you notice black smoke is the air filter. Be sure to also inspect other air intake components like fuel injectors, sensors and fuel pressure regulators. Other possible reasons could be clogged fuel return lines.
Contrary to what many car owners believe, black smoke is hardly ever a sign of something too serious to warrant immediate action. Note though, that white, gray and blue smoke should not be ignored. Sometimes two or three faulty components can mean you get thick black, black smoke where you could only get blue or white smoke if only one component was at fault. So to be on the safe side, take no chances and find where the problem is before it worsens.