CRowe14

I JUST had an oil change earlier this afternoon at my local Lexus dealer.
I was going to let the local Toyo shop do it, but it was only a $10 difference.
I had also considered doing it myself, but with a coupon Lexus was offering, the change was $85 and I felt that was a good price.
I had specifically asked for them to drain the current oil in the car (which was the oil that had been in the car when I purchased it; Mobil 1 FS), and I specifically asked them:
A. What do you use in bulk for your synthetic oil changes?
B. Do you have Toyo full synthetic 0w20 oil by the quart?
C. If yes, will you use the Toyo synth oil as the new oil after the drain?

The let me know that they get/use Mobil 1 full synth in bulk and use that for the changes, however based off of this forum, I specifically asked for Toyo synth 0w20, and it wasn't a problem.

I've driven about 20 miles, 85% of which have been highway miles and no hesitation at all,
though I must say that I hadn't experienced any before hand, nor was the car consuming/burning any oil.

7milesout

Knowing dealers as I do, they said it was no problem, because they would really just fill it from wherever they please (no problem for them). Unless you saw them select from a labeled container Toyota 0W-20 ... my guess is you got the Mobil 1, or whatever it is they REALLY stock. Dealers ... make casinos look like day care centers.

roadfrog

Must be different in the states than here in Canada. My Toyota dealer ONLY uses Toyota oil in bulk. Mobil 1 is very expensive up here.

TGMO is about 6 bucks a qt. here. Mobil 1 is far more. I buy my TGMO in bulk from them with jugs I bring in.

7milesout

Dredging this back up as a follow up to this thread. I just did the 2nd oil change of my ownership at 21,969 miles. I used Mobil 1, 0W-20 full synthetic, 9.1 quarts. Everything went smooth. I used the plastic nipple and pre-drained the cannister before removing. Works good.

The point is: Although it has been raining cats, dogs and gerbils in the Atlanta area over the last couple weeks, I've managed a couple drives in the car since then, and not 1 hesitation.

I'm chalking it up to low miles and luck.


7milesout

davisk

It's a bit disappointing to know there isn't a definitive fix to this issue or a reasoning as to why the problem is arising but there are some great theories that make a lot of sense. Whether it be mechanical or electrical, there have been many different ways that it has been resolved which makes it much harder to pinpoint a resolution. I have a 2007 ls460 base pushing roughly 120k miles, had the recall done on the valves last month and it ran great up until I changed the oil yesterday with mobile1 5w20 sythetic. Wife took it 10 miles to work, 10 miles back home then 6miles to my son's school, at this point the engine is definetely at normal operating temperature and half way home it begins to perform as decribed in this thread, the first thing that comes to mind as she's describing the issue I automatically think it's the vvti solenoid as it were in the gs400 and 300 in the past but its not throwing codes or detecting a mis fire so I ruled that out. As soon as I get home I take it for a ride and it has no power coming out of 1st and 2nd gear then starts bucking and kicking like theres no tomorrow and escalates to a decent ride as we pick up speed. I then wonder if I engage sport mode will it act the same? Surprisingly for me all issues are out of the window and I continue to drive locally 15 miles mimicking normal shifting procedures with high hopes of trying to re train the transmission to my driving style, kick it out of sport mode and it's back to normal. It may be far fetched but this worked for me SO FAR, we will see how the next couple hundred miles goes as this issue is known to return with a vengeance. This may have worked or has been a major coincidence where the issue has gone away on its own as described in prior posts, either way it's gone for now.

superdenso

davisk, have you changed the trans. fluid in this car?

davisk

Not yet, I do have this planned for the upcoming months possibly after the holidays.

Devh

Would you happen to know what oil you used prior to Mobil 1 oil.

davisk

No i dont this is the first oil change on this car for me, we've only had it a few months.

Devh

That's what I thought. The most possible explanation are deposits being cleaned because synthetic oil is being used for the first time. Deposits are being dislodged from varnish build up that accumulated from regular oil. As the oil circulates these deposits accumulate in the tight passages of the VVT solenoid, strainer, and openings to the cam causing occlusions which contributes to oil pressure inconsistencies at the cam.

Although it is true that a bad VVT valve or system will cause a CEL there might be a threshold before it does. This kind of hesitation has been reported on other cars that use oil pressure to drive the VVT cam like system when they are faulty. Specific to our issue the hesitation subsides until you change your oil again because the cleaning action of the synthetic oil is not as aggressive after a thousand miles or so.

You can try flushing the engine of the deposits as Road Frog has done or it wouldn't be a bad idea to identify the issue by switching back to regular oil and see if it goes away.

davisk

Thank you for the input and everything you are stating makes perfect sense to me. I hate to be in a guessing game when it comes to issues with our cars so it's a relief when there's a logic behind things. This car is new to me so I'm still in the learning stages of the engine but clublexus has proven to be a great community over the years. And with 120k on mine I believe I will look into what road frog did to get it fresh and start off with a clean slate. Thanks again.

7milesout

Most? Not in my mind. But we're just running laps on the same road here. Your explanation below sounds impressive and all, but it is but pure speculation, with no clear way to determine if what you say is true. Except for an engine tear-down. Nobody in their right mind is going to do that. For one thing, he said he doesn't know what oil was used before. So it cannot be said that this is the first time to use synthetic.

And another thing, if my understanding of the way the VVT system works, it needs superfluous (hey, I can use big words too! ) oil pressure provided by higher rpms, to implement changes to its mechanically driven, "normal" operation. So you're "occlusions" theory doesn't seem to hold water in my mind, I could be wrong. A low speed NOT FULL throttle acceleration, when it seems to me that this is where most folks on here state the hesitation happens, oil pressure should just be lubricating the valvetrain ... not using the oil pressure to drive the variable valve mechanism. So a momentary "occlusion" of oil would not affect valvetrain performance because in these situations, it would just be operating mechanically.

Devh

Before we begin we need to be on the same page. The bolded is not true. The VVT-i oil pressure system is only partially dependent on RPMs past idle where it has enough oil pressure to be fully operational. Once the cars RPMs are above Idle the oil pressure is constantly being shunted using a solenoid valve to drive the VVT sprocket, and it's being managed electronically with intelligence. What that means is the VVT system is constantly changing based on the management of the ECU and does not need to follow linearly its correlation based on oil pressure at higher RPMs or anywhere in between. It may make changes based on RPMs with oil pressure but it does it by management and not just by mechanical means.

Because hydraulically activated VVT cannot operate at idle they created VVT motors that are not oil pressure dependent that can take advantage of lowering emissions and increasing economy at idle along with some other benefits.

Our cars use motors for the intake valves and a traditional hydraulic system for the exhaust valves.

If we are good with this then I can explain further why I say it's most probable. If you disagree then I can't.

Devh

I suggest that you do your own research considering my probable explanation is considered controversial.
There are many other related reasons for hesitation on acceleration that has nothing to do with the oil but for some unknown reason they are lumped into this particular phenomenon which only makes trying to solve it harder than just going with the obvious. By doing simple deductive reasoning you cannot get around the fact that this particular hesitation is certainly oil change related. Not transmission related, not knock sensor related and not ECU reflash related.

superdenso

Davisk this is what I did. My car has 50k.
1. Poured a $10 Royal Purple MaxClean Fuel System Cleaner 20oz into the gas tank.
2. The car ships to the US with 5w30 so that's what I use. Cooler weather is coming soon so Mobil1 0w30 is going in this weekend.
3. Changed the trans. fluid with genuine Toyota fluid 3x to take it out of the equation.