LordBowral

I recently went on a long drive in the country where I got to drive really hard redlining the engine for a good 30 mins or more on a steep winding road ... Great fun but after pulling over for a driver swap and leaving the motor running the engine sounded really noisy and rattly with what sounded to me like tappet noise ... I drove for a further 30 mins at normal speed and the started the next morning when it sounded sounded normal... Any thoughts as to why the noise ?

1BlinkGone

Hmmm just a guess without hearing it myself- perhaps a bit of crud was stuck in a valve lifter for a bit and was washed out by oil eventually?

Devh

What kind of engine oil are you using and did you change the brand or type of engine oil not too long ago.

LordBowral

Hi ,
its done 10,000km since the last oil change and I use Nulon full synthetic 5W-30 ....

ShamanLS

Did you notice any changes in the car's performance? like the acceleration?

LordBowral

No if anything it was going even better .... Performance has never really been any different

Lavrishevo

iTrader: (1)

As others mentioned, most likely valve train noise. Personally, would not push the engine so hard as tapping or metal to metal contact is not good for the engine. Excessive heat can also play a role. Did you burn any oil when racing the motor this hard?

LordBowral

[QUOTE=Lavrishevo;9061258]As others mentioned, most likely valve train noise. Personally, would not push the engine so hard as tapping or metal to metal contact is not good for the engine. Excessive heat can also play a role. Did you burn any oil when racing the motor this hard?[/QUOTE
No oil used ... The noise was gone after normal driving and stopping after a further 20 mins . It was very cold so cooled the engine down quickly . It's is designed to rev if you've ever seen the tests they put the engine through so I don't think it was excessive and certainly not abuse as it was all within the rev range

Lavrishevo

iTrader: (1)

I agree with you that the LS engines are designed very well and can hold up to lots of hard driving but if the engine was making tapping noises and sounding ratty, as you mentioned, the logical explanation would be that oil is not circulating and lubricating as it should. I would take that as a sign not to drive it as hard. I tend to error on the cautious side but this is just me. You could try an engine flush when you change the oil and this may also help dislodge any carbon or gunk that may have clogged something up. High rpms is hard on any engine especially for extended periods of time.

Tec80

Switch to 0W20 TGMO synthetic. 5W30 is too thick and may be accumulating sludge - which melts in hard driving conditions and clogs things - creating tapping noises.

Tom57

The tapping is likely a slight collapse of the valve lifters. As noted above, a good engine flush and thinner viscosity oil should address it.

Devh

I agree with this and was going to post something similar. There might be an aeration issue.
I think all that is required is to use the Toyota 0W-20 and it will have better aeration control.

LordBowral

5w-30 is the oil that Lexus and Nulon recommend . I will try 0w-20 as its due for an oil change in 2000km .

LordBowral

Just had a conversation with Nulon the oil manufacturers technical dept and their explanation was that due to the hard driving and subsequent heat of the engine the oil had thinned and that was what caused the tappety noise to occur. Their suggestion was that if I was to drive like this on a regular basis( I don't ) to go up a grade to 10W -40 and certainly not down to 0W-20 as had been suggested as that would make matter worse when the engine was really hot . As I live in Sydney where it never gets below 10 Celsius cold weather viscosity is not an issue .

lexgolf

Just got an oil change [0W20 Castrol Synth.] and the diesel-like noise at idle is almost gone. The car has 36K miles on it, and oil was chnaged regularly every 5K miles or so.

Anyone else see a noise decrease after oil change?