My 69 Chevy Impala is leaking oil out of the valve cover breather. It also blows heavy blue smoke when i'm going down the freeway and press the gas. It only lets out a puff of smoke and then if I keep the pedal pressed at all it won't smoke. The oil splatters all over the drivers side of the engine, so i'm not sure if the smoke is being blown from the engine out the back, or if its coming from the pipes. I replaced the PCV valve, and oil cap, to no change. I don't seem to have any loss of engine power. I've been trying to locate this one for weeks.. any help would be awesome!

The most common cause of blue exhaust smoke is oil leaking past engine seals and into the cylinders where it then mixes and burns with the fuel. This is most frequently seen in older or high mileage cars with worn seals and gaskets. It only requires a very small amount of oil leaking into the cylinders to cause excessive blue exhaust smoke.

Blue exhaust smoke only at start-up can indicate worn piston seals or damaged or worn valve guides which may also cause a rattling noise. An external engine oil leak can drip onto hot engine and exhaust parts causing what appears to be blue exhaust smoke. Other possible causes of blue exhaust smoke include: piston wear, worn valve seals, a dirty or non-functioning PCV valve, worn piston rings, an intake manifold gasket leak, worn engine oil seals and possibly even head gasket failure.

Oil leaking into the cylinders can cause a rough idle, misfire and fouled spark plugs. In addition, a reduction in power and oil loss can be indicators that the blue exhaust smoke is caused by an internal engine oil leak. Internal engine oil leaks can also allow fuel to mix with the oil in the crankcase which will degrade the oil and prevent it from adequately protecting the engine.

Operating a car with a severely dirty oil filter, air filter or improperly functioning PCV valve can also sometimes result in engine oil blow-by, oil loss and blue exhaust smoke. Periodically checking the engine oil level with the oil dip stick will indicate if there is excessive oil consumption. Higher viscosity engine oil can sometimes temporarily reduce the amount of blow-by; however, this is not generally recommended. Excessive blue exhaust smoke indicates a possible internal engine oil leak that should be inspected by an ASE certified mechanic.