Strange Car Noise

toyota
engines
intermittent
yaris

#1

Hello,

My Car has been making a noise that comes and goes. It seems to be dependent on the speed of the engine and coming from under the hood. It can come for an hour and then dissapear for a week, then come back etc.

Toyota Yaris 2008
105K
4 cylinder, 1.5L engine
No turbo.

Attached is an MP3 of the noise, you may have to turn up the volume to hear as it isn’t super loud.

Note: seems to happen more often in colder weather. It sometimes happens right from startup, but other times it doesn’t start until after half an hour on the road.


#2

I’m assuming that the engine was at warm idle speed when you recorded the noise, and it sounds to me like one of the valve lifters is sticking. How often–in terms of both months and odometer miles–do you change the oil?


#3

For the last few years the car was usually only driven 3-4 days a week, so on average I would say a typical oil change takes place fairly consistently every 5 months at 3000-4000Km (1864-2485miles)


#4

My Corolla makes an rpm related noise. I didn’t listen to your sound file, so unsure if the sound is the same. The Corolla’s been doing that for 15 years! Doesn’t seem to harm anything. I figured out using a length of garden hose as a sort of stethoscope it was coming from the alternator.

A mechanic would probably idle the car and listen to the noise, perhaps using the stethoscope method to narrow down the source location. Then they’d increase the rpm with the car still parked, and listen to the difference in the sound. Then they’d take the car for a drive to verify the sound wasn’t related to the speed of the vehicle or whether the transmission was in drive vs neutral and coasting.

My wild guess is something like an idler pulley or overly-loose valve clearances. What does your service schedule in the owner’s manual say about checking valve clearances? On my Corolla the recommended interval for checking valve clearances is 60 K miles. So maybe it is time to do that for your Yaris.


#5

The Valve clearance was checked last (audibly) @ about 96K. It’s supposed to be checked again at 112K. But I think I’ll bring it to a mechanic and get it looked at.


#6
The Valve clearance was checked last (audibly) @ about 96K.

You mean some one actually told you the valve clearances were good just by listening to them? That doesn’t sound good at all. The only way to check these if with a feeler gauge. Which is a little more involved than just listening.