Originally Posted by Doublebase

With me personally I had a lot of oil tracking though the PCV system, I would even have it track through the fresh air vent side, directly through the tubes and throttle body plate. Then I'd take a look past the throttle body plate, into the intake and with a flashlight you could see the oil just pooling there right on the intake floor. I began buring around a quart every 1,200 miles. My oil usage started right around the 150,000 mile mark and then got progressively worse, but up until that point I had really not experienced much oil usage at all.

One thing I wish I never tried - especially with a direct injection car - was push the oil intervals out to 7,500 miles. Before that I was doing 5,000 mile oil changes. Now at that time fuel dilution and low speed pre-ignition were not terms talked about with direct injection vehicles...nor wasn't oil consumption. Now it's all you hear with direction injection vehicles...shortening the drain intervals, fuel dilution, and low speed detonation. Those are the buzz words now; along with catch cans, intake cleaners, better oil designed for direct injection engines, soot, and baffle systems on PCV systems.

I wonder if a valve cover PCV baffle system would improve consumption in these cars - like I said, I noticed large amounts of oil coming through both sides of mine. The fresh air side can have oil problems during heavy throttle situations when manifold vacuum is low and blowby can't escape, but honestly I was very rarely in those situations when I drove, yet my car always seemed to have it come through that side as well. I imagine my engine blowby was too high...perhaps worn rings, or stuck rings. The soot buildup on the ring lands on direct injection vehicles have been noted to be high, wonder if removing the plugs and adding a cleaning solution to the cylinders and allowing it to sit overnight might help with some of these cars? Either that or the rings were just shot. I did notice a lot of oil on my spark plugs when I changed them...never misfires, but they were fairly covered (not all of them, but maybe 4). So I guess valve guides couldn't be ruled out, but that wouldn't explain the oil in the intake. And I just can't picture my rings being shot either, I always used a high quality Synthetic and although I did go 7,500 on a few occasions, for the most part my intervals were between 5,000-6,000 miles for the life of the vehicle. But yes, I did not have the oil consumption issues until I reached 150,000 miles or so....and honestly I probably still could have driven the car to 200,000-250,000 and beyond without issue (I think) because the engine always ran so smooth...no misfires, not one single check engine light the entire life of the car and plenty of power.

Originally Posted by abs

Okay, this is very important information! The engine in the LS460 has a built in air/oil separator in the PCV system. It is a black plastic component sitting in the "V", it has a fitting that goes into each valve cover and also the PCV valve on the front. It is designed to allow liquids (oil, condensed water, etc.) that the PCV would otherwise suck into the intake, to drain back into the crankcase. I suspect that as these engines get to higher miles that the oil separator fails, allowing oil that gets sucked up into the air/oil separator to then get sucked into the intake through the PCV. So far as I can tell, this is the only way all that oil could be making its way into the intake manifold and throttle body as described above by Doublebase.

I also have a different vehicle with a Ford Ecoboost DI engine and it has a similar OEM air/oil separator setup. Turns out that at higher miles the components inside the air/oil separator (valves with rubber flaps) can fail and cause large quantities of oil to enter the intake through the PCV. This was only just identified recently on these Ford engines. The symptom is massive oil ingestion, poor running, etc.

For anyone with unexplained oil consumption on your LS460, check for quantities of oil in your intake as described above. If you find that symptom, consider replacing the air/oil separator as it may just solve your oil consumption problem. Please post your results here.

Originally Posted by abs

jdanielca -

Great work tracking down the part - that is it! Also, here is a link to a thread posted by another CL member (FatherTo1) that happens to show the part on the engine - I'm also including two photos from that thread here for reference. I've never had that part off the car or in my hands and I'm not sure how Lexus designed it. In the diagram you posted, there is a part number 12203, I'm not sure what that is, it could be a drain back valve of some type. I believe 12204 is the PCV and I'm not sure what 12258A is. In the photos below, you can see that there are at least two, and possibly three holes in the engine (front and rear) where the air/oil separator fits and connects to the engine.

https://www.clublexus.com/forums/ls-...96k-miles.html

Originally Posted by altoreid

Has any one done a compression test to see if worn cylinders or bad rings are causing the oil usage problem ?

Originally Posted by jdanielca

great good to know thanks, the only reason I’m considering this is I have the car apart at lexus to this level now anyways, no idea how it works inside but if I were to change it I guess better to change the ancillary parts too?

Originally Posted by abs

Just following up on this discussion and curious if you've seen any improvement with the new oil separator installed?