4AGE belt whine

[Vertigo]

Noticed that my engine has started making a whining sound, especially when revving down while changing gear. Ive read that this can be caused by oil on the belt, indicating an oil leak. While this is fine, will deal with that, is oil on the belt and the whine cause for concern? Most people seem to think it just sounds cool Would rather get rid of it personally.

[tsoob]

your cam belt to tight?

[Quint]

Could be a thousand things. Stabbing in the dark a bit.

I'd suggest alternator. You're basically going to have to narrow down where the noise is coming from, can be deceptive.

[AE82 FXGT]

so you cant repliacte the sound while the car is still?

[Vertigo]

Had a poke around tonight, it actually sounds like some kind of an air leak in the gearbox end of the engine bay. Going to try to find it this weekend. Could be a completely different problem tho - Im sure it sounds different when driving.

[Quint]

Stick your head in the engine bay and yank on the throttle cable. Try different rpms, holding it, revving and dropping etc. If the whine speeds up (changes pitch) at different rpms you know its something that's going round'n'round.

Noises sound different when you're driving because its competing against all the other noises an engine makes when it's under load / it's under load itself. If you think you have a vacuum leak, get some soapy water in a squirter bottle and squirt it on the suspect line/join/do-hickey. But I don't know how an air leak whines.

[79rolla]

use crc, engine start or break clean if its a vacuum leak, it will rev up wen you spray it on the leak, soapy water for a boost leak

my mates starlet had i high pitched squeaking (sounded like an alarm) took forever to find but it was a vacuum leak.

[Vertigo]

the whine has gotten pretty bad, im definitely thinking its some kind of journal surface, something thats rotating as quint says. could be the cambelt tensioner. ive taken a soundbite, its terrible thanks to my shithouse blackberry mic, cuts out constantly and has $&#$% all bass, but thats ok, singles out the noise anyway. just know that it doesnt JUST sound like this, it has normal engine sound too.

http://verti.orcon.net.nz/bad_noise.mp3

the first third of the mp3 is me holding the phone up to the cam gears to record the noise in question, dodging hoses and revving a bit, then i bring it down the the exhaust to record some popping which is concerning me a bit too, then the rest can be safely ignored as i left the phone recording for a while.

[Vertigo]

oh also, my idle has started to sporadically come down to 500rpm, which also concerns me. surely related. the worsening of this sound and the idle has come about after i overheated last weekend. thought id blown a head gasket, but ended up having the thermostat replaced and all is well temperature wise, but perhaps ive done more damage..