Engine ticking sound on low RPMs

[miku22]

Hello!

I bought this 2006 Corolla last fall and about a month ago it started to make this weird noise when the engine is warm and at low RPMs. It doesn't matter what gear I have and as soon as I give it some throttle the sound disappears. The car now has about 252000km and it was serviced last August with 241000km. Oil levels and other fluids are good. Here's a video of the noise (sorry for poor quality).

Do you guys have any idea what if could be? I'm selling this car in September because I can't afford paying insurance anymore so I wouldn't want to service it now so it will be easier to sell later. I will of course if I have to, though.

I had one mechanic friend have a look at it and he said it's just normal noise for an old engine but the noise started so suddenly so I'm afraid that something's wrong.

I'm losing sleep over this because I really want to have this car for the summer and I'm a poor high school student who can't afford an expensive engine repair. 

Thank you for any advice.

MOV_0185.mp4

[oldcodger]

Listened to it several times, but very hard to isolate any particular sound / location

There are so many things it could be such as valve clearances, timing chain, alternator, water pump etc.

Its really a problem you need to be there to try to locate the source of the sound.

Any other mechanic friends who can take a look and test it out more for you ?

[miku22]

1 hour ago, oldcodger said:

Listened to it several times, but very hard to isolate any particular sound / location

There are so many things it could be such as valve clearances, timing chain, alternator, water pump etc.

Its really a problem you need to be there to try to locate the source of the sound.

Any other mechanic friends who can take a look and test it out more for you ?

Thanks for this answer.

Could it be related to low idle speed? I have about 500-700 RPM when idling and the noise disappears immediately after hitting 900-1000 RPM.

The sound is definitely coming from the left side of the engine. I will try to locate it better tomorrow when I get home.

It started also soon after I changed to 98 octane gas. The previous owner used 95 octane. Could this have anything to do with it?

The noise itself doesn't really bother me but I just want to be sure that the car doesn't break down or something when I'm 500 miles away from home. 

[oldcodger]

Hmmm, so you are on a tight budget, yet you changed to more expensive Super unleaded ,  why  ?

Though would be surprised if changing to a higher octane would cause such a noise, possibly more likely you are being more sound/engine aware ??

What does it sound like if you change back to 95 octane ?

There are many breakdown recovery schemes around, just  web search for the best ones /prices in your area, then you have peace of mind.