ryoo1257

Yes the knock goes away as one accelerates more. I will try and see if this knock is sustained if I don't 'punch' the accelerator.

ryoo1257

I tried Shell, Chevron, and Mobil. Shell was best, Chevron, then Mobil.

ryoo1257

What's a CVT?

Not any loose exhaust or cat converter...technicians identified it as knock. If I recall Lexus advises only regular in this car, correct me if I'm wrong. But, they put 91 in it and said try it.

ryoo1257

This 67 year old I know has this vehicle as well, but he drives like an 'old man' I don't have a heavy foot and putting it in Eco, Normal, or Sport still evokes this knock.

ryoo1257

Once the tank is low, I will try Techron and see if it cleans up any Costco crud buildup which the brand name gas with it's additives have not addressed...skeptical though.

lesz

I probably should have said this in my earlier posts, but my thinking was that the sound that you are hearing might actually be the engine lugging. Engine knock and lugging can have fairly similar sounds, and they can occur under similar circumstances, especially when the automatic transmission is selecting a gear that is higher than what is called for in situations such as climbing up a hill, and that is when using the accelerator pedal to cause the transmission to use a lower gear is called for.

CVT is a continuously variable transmission, which is what is used in the ES300h, while a conventional transmission is used in the ES350.

If what I'm thinking is possibly the cause of what you are hearing, it would be the result of having a "light" foot and would not be happening if you had a heavy foot.

Arty101

So the CVT uses conventional gears? I heard that CVT don't "shift" like regular automatics to improve mpg.

lesz

No, it doesn't use "gears". Instead, it uses friction. I just use the term "gear" in a more general sense to refer to the gearing ratio that is being used to propel the vehicle. Perhaps, there is a better term that I should be using, but, if there is, it isn't coming to mind.

Arty101

Lesz- I agree with you. I think engine lugging can sound like engine knocking. If the CVT is "gearless" but continuous, would the transmission wind up and allow for higher rpm as to not lug? I really haven't heard my ES "lug" and I drive up some steep hills in San Francisco. Don't get me wrong, it is definitely louder and noisier than normal, but not to the extent of lugging or knocking.

lesz

With the CVT, just like with a conventional transmission, I think that whether and when it adjusts its setting/gearing depends on what the driver is doing with the accelerator pedal. It is just like if you are on the highway driving 60 mph and you want to accelerate quickly to pass someone. When you step down quickly on the accelerator, the transmission responds by changing to provide a lower drive ratio, which will provide the power needed for the more rapid acceleration, and, again, if a driver has a very light foot, the transmission is going to be inclined to stay with a drive ratio that is too high and that doesn't provide the power needed to accelerate quickly (or to climb a hill).

(Note that I'm still struggling to find the right term to use for a CVT that would correspond to changing gears with a conventional transmission. )

GSGenesis

Here's my .2 cents on this. I live in a part of my town that requires me to drive 3 miles uphill to get home everyday. It gets VERY steep once your about 70% of the way up. First off it's your car pinging obviously for a reason. I hear my car ping best when I'm passing a parked car, with my passenger window down, on the steepest parts of my climb, load on motor... (You'll hear it echo off the parked cars)
Reason being: When I don't run 91 octane. My Gs is a ***** and knows when I'm not running premium, and makes sure to know I know, she knows... LOL!
If your cars pinging, you need to raise the octane in order to raise the combustion temperature of the fuel to avoid combustion... (What causes pinging)
Certain companies make my car ping and some don't. First you need to clear the carbon deposits which aid in pinging a lot more than you imagine. It builds a heat barrier which significantly increases an engines combustion chamber temperatures. So if your running 91 or 93 and still pinging, well, not saying it's for sure! But you could have a lot of build up, or simply the wrong dam plugs or gaping. So... Run some sea foam through a vacuum line, I do half a bottle though the line, and the other half of the bottle in my fuel, read up on how to correctly do this... Wanna see what's built up? Hahaha oh you will just take a look in your rear view mirror when driving after shooting it directly through the line. It's actually very healthy for the motor and is a sufficient way to get what we can, out without actually getting in there and doing so... My car seems to like 76, and chevron... Not sure why... But... I'm not that into it to break down what additives and how much each company uses to care. I can just tell by the way she purrs

Arty101

So are you talking about running premium gas in your GS? Yes, I run premium on my GS too but the ES should run on regular.

Your sea foam sounds like a colonoscopy cleansing for cars .

bc6152

Sea Foam? Higher octane than recommended? Both wrong IMO. Use the gas that the manufacturer recommends and NO additives. These cars should not be pinging under ANY circumstances. Uphill, downhill, light foot, heavy foot, window down, window up, etc. These engines are controlled by a computer that adjusts by the millisecond to the various conditions.

lesz

I agree. Even when, for the ES 350, the same engine was used as is used in the current ES350 for several years with a Lexus recommendation to use premium fuel, the wording in that recommendation indicated that optimal performance would be achieved with premium fuel, but 87 octane was satisfactory, and the vehicles performed with no issues with 87 octane fuel. Further, the primary reason, back then, for recommending premium fuel did not really relate to engine performance. Instead, it was because, to meet the EPA's requirements for a higher emissions rating, the recommendation for premium fuel was required.


And that is the reason why I think that there is, at least a possibility, that what the OP is hearing is actually lugging. My suspicion that that might be the case is bolstered by the fact that the dealer's service department did not find anything amiss with the engine's operation, and that could be the result of the service adviser or technician driving the vehicle while using the accelerator differently and in a manner that was more likely to cause the transmission to be responding more appropriately relative to what was called for when accelerating or climbing a hill. While I can't dismiss the possibility that there is a genuine problem with the engine, I also have a hard time believing that, if there was a genuine problem, it would not be readily apparent to the people in the dealer's service department.

alpinefun

How about malfunctioned knock sensor?