GS 300H engine noise

arkviz · May 28, 2016

Hello everybody!
I am driving GS300H for about a month and i am very satisfied with it. This is not a real issue but i think it is interesting. I had many cars before this and all of them were much louder after cold start. Warmed up engines were always quieter. Now it is different. When I'm driving using power from cold ICE, car is extremely smooth. It feels like as smooth as 6 or maybe 8 cylinder engine. There are 100% no vibrations and only barely noticable engine whistle. Maybe You laugh but comparing to my previous turbo I4 it feels so nice. But... When ICE warms up, it's more like ordinary 4 cylinder, especially at low revs. It is not bad, but when ICE is cold, it is much nicer. Did You realized it too?

Zotto · May 28, 2016

Not sure about understanding what you wrote, I have a GS300h and did not notice; have you made a service with oil change? GS 300H OIL is 0w-20, may be a different oil could create this effect.

Ten Ninety · May 28, 2016

Is it because when the engine is very cold, it's actually the electric motor which powers the car? I think when you first push the Power button the engine starts up but doesn't provide power to the wheels until it's warmed up a bit, although this doesn't usually take long at all. The car does drive differently for that first 30 seconds or so - maybe that is what you're experiencing?

arkviz · May 28, 2016

6 hours ago, Ten Ninety said:

Is it because when the engine is very cold, it's actually the electric motor which powers the car? I think when you first push the Power button the engine starts up but doesn't provide power to the wheels until it's warmed up a bit, although this doesn't usually take long at all. The car does drive differently for that first 30 seconds or so - maybe that is what you're experiencing?

Yes this is what i suspected it to be. Today i was driving through mountains on twisty roads (car handled very well) and I've noticed another thing related to that noise. If there is no power coming from electric motor, noise is there, if electric motor works and helps ICE, noise is gone. My conclusion: Engine itself is relatively rough under load. It has nothing to do with oil, as i have only 2300km on ODO. Anyway, the car is really sweet.

Zotto · May 29, 2016

Have you experienced this at a speed around 50mph? If so it could be a vibration corrected by a new calibration affected in 2.5 liters engines equipped in IS and GS 300h, in forum you can find about this topic.

arkviz · May 29, 2016

I've read all that "vibration" conversation and before my purchase, i tried IS300h (about 33000 km ODO) and another one pre-facelift GS300h (about 800km ODO). I can say they both and my car too have slight feeling of low revs at that speed. For me this is not problem. My previous car '13 528ix was vibrating much more at whole speed range because of low revs 900-1300. This is common problem of a 4 cylinder and it's flat plane crankshaft. I would compare it to riding a bicycle on incline. It has the same power delivery per 1 revolution without overlap. There is small phase when each piston moves only inertia and it leads to vibration. It is very difficult and physically almost impossible to make silky smooth, efficient and powerful 4 cylinder engine. Regarding this, Lexus engine is very well balanced.
Noise I was talking about in my first post, is perceptible primary at low speed or idle if engine runs and traction Battery is low. It is similar to empty tinny bucket droning. Maybe it comes from exhaust. It sounds like exhaust on this video at 18:00 right after revs dropped.

arkviz · May 29, 2016

And another video of IS300h at 24:20

Zotto · May 30, 2016

I will try to reproduce it on my GS, may be it is a resonance from exhaust, or just engine gargleing :)

arkviz · June 1, 2016

I would rather have engine whispering :-) Today I've found something new about this noise issue. I was driving through underground parking garage, windows down and engine was really noisy and engine sound was very coarse. 20 minutes later engine was slightly colder but much quieter. My idea is, if valve timing can do this noise? After start cold timing is different than warm valve timing + there is Atkinson cycle, which may increase noise.