hi, my 2016 is300 got light taps on the engine recently, I drove it to my mechanic, and he said the valve clearance is a bit loose, but it's totally fine, no need to fix it.

I went home and did some research, loose valve clearance can lower fuel efficiency. That explained why my fuel efficiency has dropped a bit recently. So my question is, does my car have hydraulic valve? if so, can it be adjusted? thanks

 

You had me curious, so I also did a little Googling.

All modern IS engines have hydraulic lash adjusters. See:

• https://www.motorreviewer.com/engine.php?engine_id=129
• https://www.motorreviewer.com/engine.php?engine_id=139
• Even the V-8... https://australiancar.reviews/2UR-GSE-engine.php

It would seem that these do not need regular adjustment.

https://en.wikipedia.org/wiki/Hydrau...r%20adjustment.


With all this in mind, I revisit what your mechanic said. First off, when you wrote "light taps", can you describe this issue in a bit more detail?

Also, how many miles are on your car?

 

the taps usually happens when outside temperature drop to around 10 degrees celcius or when cold start. Sometimes its prominent, sometimes it's unnoticeable.

I heard even hydraulic valve can be adjusted, there are videos on youtube. I guess the valve is stuck by dirt so it doesn't self adjusted or something. my car is 44000 km.

 

That's not very high on the odometer; I would not expect this issue yet. Have you or the previous owner(s) consistently changed the oil? It should be done every 10,000 miles (or 16,000 km). Sometimes improper maintenance could cause this issue.

I've literally never heard of a 3rd-gen having this issue. Are we sure it's not a belt or belt tensioner or perhaps fuel pump or fuel injector?

 

Do you have a video of the "tapping"? The high pressure fuel pump is noisy and can increase/decrease in volume. Mine does that and Lexus told me it is normal. Been driving like that for few years now.

 

my mechanic said it's not the GDI injector. I didn't drive it that much since the pandemic, so I didn't change the oil close to 12 months. But since I changed the oil 2 months ago, it seems the noise has subdued a little bit, from low frequency tapping to high frequency light tapping, less noticeable even in cold weather. I supposed the clearance has decreased a bit. I still haven't driven it on highway since the noise began, I will see if a high speed drive will loosen up the valve or not.

 

can you hear the high pressure pump in the cabin? I own the car for 4 years and I have only heard the fuel pump ticks for a few times only, in the first 2 years. Then the pump ticks has completely disappeared until I heard this noise 2 months ago.