why is this clicking?

[Fun_Bucket]

My motor has been making a clicking noise from the part pictured, can some one tell me why it might be doing this? It's been doing it for a few months now, and also today i switched from a 40W to a 60W oil, and the motor itself now is a lot quieter, and maybe even a little smoother, but now more than ever i can really hear this clicking noise. The motor also misses while its idling too..Also, does there appear to be something missing where there's a thread, like where a screw belongs or something?

[Not_An_Abba_Fan]

That is the belt tensioner, they tick because they wear and are dry. You could try spraying it with lubricant so it penetrates where it pivots, but it probably needs replacing.

[pow3rslave]

^^ what he said
just watch out when you're spraying lubricant that you don't get any on the bit that contacts the belt, or it'll slip and make a godawful screeching noise.

also it won't be the cause of any missing, it just holds tension on the belt, when the bearing goes it will sound clicky/grindy, but it's also right next to the power steering pulley, so that might be the source of the click (dead bearing in there maybe)
nothing goes in the threaded holes in your photo, i don't know what they're for but you're not missing anything.

[Fun_Bucket]

are belt tensioner's expensive to replace? and should i replace anything else while i'm at it? Could a worn out timing chain be responsilble for the miss? Oh and i've taken the power steering pulley of (assuming that was the black plastic one with what looks like a skateboard wheel bearing in the centre of it?) and it was ok..

[grim596]

My tensioner bearings got stuck and the whole thing literally melted on the pacific highway just north of Urunga, a couple in a VT pulled up to help, funnily enough they had exactly the same happen the day before in QLD, $25 for the tensioner, Metal one this time (not original plastic) $75 for the belt if you tear that up at the same time.
I've heard that if this goes your water pump isn't long off either, so may want to look into it if it hasn't already been replaced.
I can vouch for this, my water pump went not 3 weeks beforehand.

So that was 2 $75 belts in less than a month

[Vlad01]

$75? i thought my non A/C belt was expensive @ $46 where regular belt is 35