It's been rather cold the last few weeks up here in Scandinavia, and I've developed a strange ticking noise from my engine bay. I'm wondering what it could be. I've yet to read the fault codes, but I've had no other error ligths than the odd 'low coolant level' on really cold mornings, which stops after one restart. If I gathered correctly, it is quite common that this error light comes on on cold starts (under -5C); apparently a scraping of the sensor should help.

Anyway, the noise I have seems to be coming from the front right of the engine bay (it's a left-hand drive '04 Octavia vRS, 35k miles) and I can describe it best as a ticking noise. Frequency is maybe twice a second or so. It sounds a bit like a watch, but more loudly. It doesn't depend on engine revs, and I hear it most clearly on idle (least engine noise, I guess). I can hear it from within the cabin as well. It's a new noise that has occured only the last two weeks.

Any guesses on what it could be or how to diagnose? Thanks!

Isn't it coming from a black canister between the washer and coolant bottles?

Isn't it coming from a black canister between the washer and coolant bottles?

If it is, would that be the charcoal canister that filters the exhaust fumes?

And if it is, why has it only recently started doing that noise? I am quite certain that it has not done it prior to the last two weeks. I've had the car since May last year. Could it be the cold weather making the noise louder?

Is it fixable, or does it even need fixing?

Mine does exactly the same mate, I just assumed it was something like wasted spark

Yes sounds like the charcoal cannister.

The noise is normal and nothing you can do about it.

Probably because you are now aware of the noise it seems louder or it may be that the cold is making it a little louder than normal.

I only noticed mine last week too and thought ah thats the ticking I've heard about it is quite loud especially with the bonnet up

Ian

If it is the canister and it is doing it whilst the engine is cold, then you do have a problem. A bad temperature sensor can cause this. The purge valve should only release the stored vapour to be burned when the engine is warm.

The purge valve on the canister can go bad. You should here a click. It it is more of a buzz or whistle then the valve needs replacing.

Dunno about the carbon can, but you're right about the cause of and cure for the spurious overheating/low coolant warnings.

If it is the canister and it is doing it whilst the engine is cold, then you do have a problem. A bad temperature sensor can cause this. The purge valve should only release the stored vapour to be burned when the engine is warm.

The purge valve on the canister can go bad. You should here a click. It it is more of a buzz or whistle then the valve needs replacing.

Actually, I forgot to mention that I only get this sound when the engine is warm, so it would indeed seem like this sound is nothing out of the ordinary. Now that I know a bit more, I will diagnose the issue further.

Thanks to everyone for your help so far!

When you hear it again, jump out, pop the bonnet and stick your finger on the black box. You should be able too feel it ticking.

Same thing with my Octy, when it's ticking I know it's working.

Mine's only started ticking recently too (starts about 30 seconds after the car starts even when cold) and I've noticed a smell of petrol coming through the air vents and even standing outside the car at the driver's door.

Could this be causing it?