Okay so I’ve got a 2014 Scion tC. It’s got 250k miles on it and I’ve got a bit of an issue I can’t quite figure out. At cold idle it idles just fine, then when it warms up it’ll sit at a normal idle around 500-700 rpm’s but when I press the gas pedal I get some white/blue smoke. I’ve replaced the PCV valve, checked spark plugs, checked compression, cleaned the intake sensor, all that.

I also recently replaced the upstream O2 sensor and was thinking about replacing the downstream one next, thinking maybe it’s getting a bad reading AND because I also had a code showing that the upstream sensor needed to be checked/replaced.

figure someone on here might be able to help me diagnose what the issue is or has had a similar thing happen with theirs. I love this car and I don’t want to throw a new motor in it unless I really have to. Any help would be much appreciated. I’m sure there’s something I missed telling you all but, thanks!

 

Is it white or is it blue...white would be indicative of water getting into the combustion chamber and blue would indicate it's oil. Big difference as to where you might start looking...

 

it is blueish not white. Not like a super dark blue but it’s definitely not black and it’s not white white.

 

also, if I give it gas while idling and it’s warmed up, the RPMs will drop down to about 400 and then slowly come back to the normal 600-700 range.

 

Is it throwing any codes?

 

Next time you "cold start" the engine.........don't let the engine immediately drop down to it's high (cold start) idle once it fires up.

Instead.....as soon as the engine fires up.....rev the engine for a split second to around 3,000rpm and immediately look at the exhaust.

When doing this......if you see a larger amount of blue smoke (than when it's cold).....you know that oil is getting past the lifters & valves and burning in the combustion chambers.

.....and if this is what's happening, you could try using a thicker grade oil.

When my car engine started showing symptoms of burning oil, I switched to 20w50 weight oil.....pretty thick oil, but at 300,000 miles my engine was tired. Switching to this thicker oil helped my car reach 385,000 before the engine finally died.
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Im working on a 2011 scion tc with 2.5 engine.. Trying to change the PCV Valve.

Can i ask how you accomplished this?

I see videos on the camry 2.5 ar being done,,, but i dont think i can do this from the wheel well on the scion TC. Havent seen anyone else do this on you tube.