RX-Fanatic

Getting a puff of blue smoke when I start my RX330 ever so often (even on warm days).

Just wondering what the culprit is most likely? Valves, seals, pistons, etc...

Any suggestions on the cause and/or fix? Unfortunately, my bumper to bumper warranty has just ended...

Thanks.

Lexmex

water vapor on the tailpipe.

I should add that in the combustion process, there is a little oil that does get in the combustion process out of the crankshaft, though PCV valve and crankshaft vent, and this can cause a little blue smoke from time to time.

NXOwner

It's rare that blue smoke should appear out of the tailpipe--in an RX or any other late model vehicle. Since (generally) no other vehicles are experiencing this blue smoke, then it could be something unique with RX-Fanatic's car. I would suggest having it looked at, if this issue persists. Also, keep an eye on your oil level. RX-Fanatic, is your car under warranty?


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Lil4X

Watch your oil level - you may be getting a little leakage down the valve guides - a common complaint of owners of small block Chevy's in the past. These engines had rather soft guides and were prone to a puff of blue-white smoke on start-up - but it was not a serious problem, no more than a few drops of oil were being lost. You'd be amazed at the amount of smoke a single drop of oil can make. Chevy owners used to take comfort in the fact that it meant that the valves were being lubricated . . . .

Lexmex

Down here it happens a lot more than normal. I have seen an X5 and a Ford Expedition that park next to me, both newer vehicles fire out blue smoke on startup, but for less than 5 seconds. Down here, the vehicles also tend to use a higher weight oil that tends to not burn as easily in the combustion process in terms of the crankshaft gases. You are correct to check out the oil level.

The G Man

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.

RX-Fanatic

Engine oil seems to be overfilled quite a bit... I'm thinking of draining the existing oil and refilling with pure synthetic.

There was just an oil change done about 1000 kms ago, so I don't think I will replace the oil filter right away. Should be okay right?

Synthetic and regular oil mix anyways and I will be draining most of it...

Lexmex

Yeah, you will be okay on not replacing the filter this time around.

TunedRX300

I would check the compression read of the engine to get another data point.