Byprodrive

iTrader: (1)

Don't use 0w- oil & especially Mobil 1 search the internet & read all you can on this subject.

Rmccoy

After reading and my own experience, I believe the oil consumption is a direct result of the valve cam recall on the GS model cars. I'm just barely what could be considered a shade tree machenic which certainly doesn't make me qualified to diagnose the issue on a car with the amount of technology my 2008 GS 350 has. However, when I apply simple logic to a combustion engine, it's not difficult for me to conclude that when there's a combustion event in the cylinder of any combustion engine with valve timing that might not be ideal, the result could be the combustion exhaust utilize the exit of least resistance.

If valve timing is off enough where the exhaust valve isn't open when the combustion exhaust needs to exit, it makes since to me that the combustion exhaust might be forced to exit the cylinder by pushing past the piston/piston rings causing the rings to lose thier seal or worse causing the cylinder walls to assume an oval/egg shaped form.

In either case, it would certainly increase the amount of blow by associated with the engine. I noticed no oil consumption prior to recall done to my around 85k miles which is why I believe the issue is directly related to the valve cam which controls the valve timing which controls the exit of combustion exhaust.

My thought is the combustion exhaust exiting past the rings prior to the recall being done prevented the blow by from occurring. Once the recall was performed, the combustion exhaust began exiting the cylinder properly which created the opportunity for blue by the occur now that the exhaust had reversed its exit from the cylinder by being released via the exhaust valves instead of by the rings or newly egg shaped cylinders in my engine.

NickTee

If there was a significant amount of exhaust blow-by, you would have been getting significant crankcase pressures that would cause other issues, such as the PCV system being overwhelmed and oil going directly into the intake plenum through the breather hoses.

Rmccoy

Is the PCV valve the only crankcase ventilation? I often noticed a weird smell from my car that I assumed was some sort of ventilation for my engine.

Would the PCV valve have the ability to accommodate a smaller portion of the exhaust. Just enough to utilize the alternative exit but not enough to exceed the capacity of PCV valve?

It's very hard for me to except my kids of oil without a cause. I've got 60's and 70's dated old Chevrolet blocks in scopula cars I have that use less oil than my lexus with more miles on them. I'd hate to come to a conclusion on my car that it was just poorly engineered considering the quality they're so quick to claim when selling you the car new.

NickTee

PCV=positive crankcase ventilation.
https://en.wikipedia.org/wiki/Crankc...ilation_system

There is inevitably some blowby involved with engines, which is why they have the PCV setup. Rather than venting to atmosphere, the minute amount of pressure is vented back into the intake. The problems start when the PCV valve fails or if the crankcase pressure exceeds the normal values that the manufacturer expected when they made the system. Then, as I said, it can start blowing oil directly into the manifold and you burn oil that way. This is why some people use a catchcan, which will collect any oil that would have otherwise gone into the intake.

I cannot tell you the specific capabilities of your PCV system, but what you're experiencing is likely not a decrease in blowby. What would be interesting is to install a catchcan on your car, you'd have to Google the specific instructions of installation, and see how much oil is caught in the catchcan. This would tell you if you're losing a lot of oil through the PCV system and into the manifold.

xbladex00

Interesting read, I have the 3.5 V6 and i still havent done my recall for the valve spring? I'm guessing the most recent recall for the GS for a possible fire... Anyways I check the oil stick looks fine to me, if i remember the porcedure it was to remove the stick wipe it and reinsert it and take it out, see if oil is on the 2nd dot from the bottom of the dip stick.

I'm about to do an Oil change by myself soon maybe when i poor back into the containers I'll see if I lost any oil at all.

Gotcha350

If it's not low on the dipstick then don't waste your time trying to measure it by pouring it back in the new bottles...that's not accurate anyway.

Trust me....if you had an consumption issue the oil would be low.

I continue with my oil changes every 6 months with Pennzoil Ultra Platinum. I do it just to have a lil something to stand on if I have any issues....at least until my warranty expires.

daddyduke

And this is why the 430s will always be the king of all lexus of any time im just staying this because I was about to purchase a 09 350 and sell my 2g430 just to get a few more mpg.and this is the same engine on the new 350s im good Im just gonna find a 06 07 430 and call it a day when ever that times come.

xbladex00

Well... I have no where else to put it afterwards so... I put the old oil from the drip pan into the container that had the new oil. So it kind of works out.
I sort of referring to the recall maybe it was the recall which caused the problem in the first place? maybe it was instructions to start causing our engines to eat oil. Then again I'm always a bit paranoid about shops and stealerships

Gotcha350

I had the valve spring recall and the VVT cam gear replaced twice...no oil issues for me...I have no issue with my dealer...if I don't like something I bring it to the service managers attention and it gets addressed.

NickTee

I wouldn't say that, the 2GR gives it a run for its money in both fuel economy and longevity. Not to mention the versatility, since it's used in the ES, Avalon, Camry, Sienna, RAV4, RX and the direct-injection version 2GR-FSE in the IS and GS. And the 2JZ engine is also quite legendary.

bayer

Sorry to be resurrecting an old post,but has anyone heard any news of support from Lexus on this issue. A friend of mine with a 9 year old Tacoma had a front cross member rust off and Toyota replaced the whole frame,about 1 week work for 2 techs at what cost.Hard to believe the 30 some posts about oil consumption in this thread and I guess we must be the only ones.I did see a forum where a guy got his gs300 engine rebuilt by Lexus with a lot of pictures and it looked like a big operation

pbxcomm

According to what research I've found about the Piston/Ring configurations on these motors, only the compression rings are made of softer material (cast iron perhaps) and the oil rings are a chrome composite of sorts that are of harder material.
I haven't owned my 08 GS 350 long enough, but in the last 3,000 miles the oil seems up to the line. If these engines are "burning" oil, obviously not leaking , then its a quandry what part of the engine is consuming all of this oil. I would think plugs would display a oil residue over time, but I haven't read complaints of dark colored or oil residual plugs.

Lukas99GS

I don't think the 460s have any problem with this, I've just hit 160k, and have never burned any oil between changes. The rattling problem can also be fixed as my car has never rattled once. I have heard from mechanics that toyotas can burn oil if the oil isn't changed frequently enough over time. I was told you should never go 10k even on synthetic, told me it's much better to change every 3-4 on normal and 5-6 on synthetic. Also I've read a lot on the 4GS forum as I plan on getting a 13-14 350 as my eventual replacement and almost no one has reported any issues with those yet, I'm wondering if Lexus changed anything with the engine to prevent that from happening?

Skylar978

iTrader: (1)

There are not many stories with the 4GS as it is still fairly "New". I would wait another year or two to see the consensus IMHO.

I do not ever remember burning oil until I got the recall work done, but I am way out of warranty at this point and this car is just a money pit at this point for me since im modified and have AWD.