So i went to start my car after coming from the Store and there was Blue smoke coming from the exhaust Pipe for about 10 seconds then cleared up. Car has 260k i use regular castrol 5w30 oil and just changed it. The car has only done This twice since Ive owned it in 2 years. Do i need to be worried??

 

Smoke Colors
Exhaust is generally colorless, but can take on a color if it's contaminated. White smoke is actually steam from water in the engine, black smoke is generally an excess of fuel, and blue or gray smoke is oil. Some white smoke is normal, particularly just after start-up and in cold weather. Black smoke generally comes with a powerful fuel odor and is not atypical for diesels. Oil smoke also has a telltale odor, and may occur at idle or higher in the rpm range, depending upon the source of the oil.

Leaking Valve Seals
Leaking intake valve seals are among the most common sources of oil intrusion. An engine's intake valves pass through the top of the intake port and into the top-most portion of the head where the valvetrain rests. A rubber or plastic seal keeps oil from the upper cylinder head from being drawn down the valve stem under the force of engine vacuum. Leaking valve-stem seals will typically produce a greater volume of smoke at idle or under sudden deceleration, when intake manifold vacuum is the highest.

Bad PCV Valve
Even the best piston rings don't create a perfect seal; a certain percentage of combustion gasses will sneak past them and become "blow-by" in the crankcase. This blow-by increases pressure in the engine block, encouraging oil leaks and potentially blowing out an engine's gaskets. Blow-by is also extremely nasty from an emissions point of view, which is why we use positive crankcase ventilation systems to suck these gases out of the engine block and back into the engine's intake. PCV systems use a valve to prevent oil intrusion; if it sticks open, then oil will work its way through the PCV tube and into your intake. Oil smoke volume may increase or decrease by rpm, depending upon where the PCV tube attaches. Follow the hose from your valve cover to the intake tube or manifold then inspect the inside of the tube or manifold for streaks of wet oil.

Ineffective Piston Rings
Loose piston rings aren't necessarily worn out, they're just too small for the bore. Every engine experiences bore wear over time; the springy piston rings will compensate for a certain amount of it, but can only expand so much without sacrificing some of their tension on the bore wall. This is an important distinction to make, since bore wear not only decreases ring tension but increases the size of the ring gaps. Lower tension by itself will contribute to a certain amount of smoking, but the ring gaps are a more serious issue. To test for excess blow-by resulting from ring, bore or piston failure, remove the oil filler cap on the valve cover and put your hand over it. A regular puff of hot gas against the palm of your hand indicates excessive blow-by in one or more cylinders.



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That about sums it up. ^

 

When I did the rear valve cover gasket there were tiny oil spots on the intake manifold gasket. I will get a new pcv and see if that helps. I replaced it maybe a year and a half ago.

 

another possibility.
the sparkplug tube seals that are in the valve cover can start to leak letting
oil down onto the plugs. in some cases that oil can seep past the plug and cause the issue mentioned on startup. this happened to me on one of the rear valve cover seals a few years ago. when i did the gasket i also did the seals and have not had blue smoke since

 

That too. Check your plugs and your coils to see if there's any oil on them or if there's any oil in the spark plug wholes.

 

Highly unlikely, positive cylinder pressure and atmospheric pressure on top of the plug combined with crush washers and 28 ft/lbs of torque says it wont happen.

Check you PCV valve, when shaken it should rattle. Bad rings will smoke on acceleration. valve seals will cause oil burning at start up and deceleration.

 

Pcv is good because it rattles and I jus put a new gromet under it.the last time it smoked on startup, was over a year and a half, and it was on a very hot day. But I will pull the plugs and the coils and check them

 

I did get a check engine light the day before after doing a little agressive driving, gonna pull the codes today.

 

No

 

260k miles, still runnin strong.

 

yessir hasn'nt done it since then.

 

Did you decel hard and then turn it off before this happened?

 

no, i did a little agressive driving on a back road, check engine light came on, 0707 I think for rear 02 sensor, drove it a little, then went to the store. I was very hot outside, I went to start it, it was a weird startup like something was out of sequence, looked in the mirror saw the blue smoke for about 10 seconds, then it cleared up. It hasn't done it since then.