Blue smoke is never a good thing....
Blue smoke is caused by engine oil entering the cylinder area and being burned along with the fuel air mixture. As with the white smoke, just a small drop of oil leaking into the cylinder can produce blue smoke out the tailpipe. Blue smoke is more likely in older or higher mileage vehicles than newer cars with fewer miles.
How did the engine oil get inside the cylinder in the first place? The car has many seals, gaskets, and O-rings that are designed to keep the engine oil from entering the cylinder, and one of them has failed. If too much oil leaks into the cylinder and fouls the spark plug, it will cause a misfire (engine miss) in that cylinder, and the spark plug will have to be replaced or cleaned of the oil. Using thicker weight engine oil or an oil additive designed to reduce oil leaks might help reduce the amount of oil leaking into the cylinder.
your engine has worn valve guides, piston rings An engine that burns a lot of oil (more than a quart in 500 miles) is an engine that needs to be overhauled. Normal oil consumption should be a quart or less in 1500 miles. Most newer engines consume less than half a quart of oil between oil changes (every 3000 miles). So if your engine is burning oil, it's essentially worn out and needs to be repaired.
Because the cost of overhauling or replacing an engine often exceeds the value of an older car or truck, many people will just keep on driving a "mosquito fogger" in spite of the blue clouds of smoke it leaves behind. Never mind the pollution it causes, oil is cheaper than a new or rebuilt engine they reason. That philosophy may be okay if you live out in the sticks somewhere. But in urban areas that require periodic vehicle emissions testing, an engine that's burning oil usually won't pass the test because of excessive hydrocarbon (HC) emissions. You may get by on a waiver after you've spent some money (in vain) on a tune-up, but the fact remains you're still a polluter.
An engine that burns a lot of oil will also eventually foul the spark plugs. Thick, black oily deposits build up on the plugs until they cease to fire. Then the engine misfires and loses power. Cleaning or changing the plugs may temporarily solve the problem, but sooner or later they'll foul out again.
Forget about "miracle" oil additives or pills that claim to stop oil burning. They don't. Better to save your money and put it towards a valve job and new set of rings.
Feb 23, 2010 |
1990 Ford Festiva