Mystery Engine Noise?

[JonnyH]

Hi All,

I'm currently looking for an S2 estate and I had a look at one last night. I've read everything I can get my hands on, including the s2central.net guide, which is excellent.

I noticed though, that when I was listening to the engine with the bonnet up, and I gently blipped the throttle lever, I could hear a sort of dull rattle kick in at a certain rpm, then disappear as the revs climbed. I couldn't see the rev counter so I can't give an exact figure, but it wasn't much above idle. It only rattled whilst at a particular frequency, maybe about 1200-1300 rpm, I could hold it at the frequency and it would persistently rattle. It was coming from behind the engine block. I presume this is the turbo spooling up, but I'm not sure if this noise is normal or a sign that the bearings are shot. Can anyone give me advice on this?

BTW, excellent forum - it's nice to find a forum where people actually say useful and interesting things rather than posting for the sake of it. Keep it up!

Cheers
Jonny

[Ski]

in neautral/1st gear mine rattles like hell above 4k rpm. Its a heatshield i cannot be bothered fixing

[porkkis]

Could be a bit tired cam chain. Nothing to really worry about in a dizzyless ABY.

Or then a tappet noise.

I'd stay calm.

[dan_b]

Welcome!

Could be the engine undertray vibrating, or a heatshield wobbling. Also could be a lose exhaust fitting - I've had all three on mine, nothing serious.

Good luck finding an Avant, you've come to the right place for advice!

[PeteRR]

Mine does exactly the same thing.
If it has a distributor (3B) it sounds like it could be the dizzy gear. Either the gear is worn, there's a bit of end-float in the dizzy shaft or, as porkkis said, the cam chain has a bit of slack that kicks up the gear mesh of the cam and dizzy drive.

If its an ABY then the bet is the cam chain.

Any of which can be fixed relatively easily!

[Jamo]

Hi All,

I'm currently looking for an S2 estate and I had a look at one last night. I've read everything I can get my hands on, including the s2central.net guide, which is excellent.

I noticed though, that when I was listening to the engine with the bonnet up, and I gently blipped the throttle lever, I could hear a sort of dull rattle kick in at a certain rpm, then disappear as the revs climbed. I couldn't see the rev counter so I can't give an exact figure, but it wasn't much above idle. It only rattled whilst at a particular frequency, maybe about 1200-1300 rpm, I could hold it at the frequency and it would persistently rattle. It was coming from behind the engine block. I presume this is the turbo spooling up, but I'm not sure if this noise is normal or a sign that the bearings are shot. Can anyone give me advice on this?

BTW, excellent forum - it's nice to find a forum where people actually say useful and interesting things rather than posting for the sake of it. Keep it up!

Cheers
Jonny

Ask the seller what type of oil he's using in the engine.

I had something similar when using 10w40 oil and once it was change to 10w60 couldn't hear anything.

[s2avant95M]

i guess it could be all of the above and more, i have a rattle at 3k-4k, its doing my head in. where abouts is this Avant? maybe its near a forum member, im sure someone would have a look at it if it is.

[JonnyH]

Cheers everyone - thanks for the advice.

I've attached a picture (original photo courtesy of s2central.net) which shows where my untrained ears traced the rattle to. It's not like a loose heatshield, more mechanical in sound, like a rotating component which vibrates at a certain frequency. Is this where the turbo is located, or is it at the front left? Or is this the camchain - I thought that was at the front....

It's an ABY - if it is a camchain, would it likely be a case of adjusting the tensioner or would I have to get a new chain? (didn't realise it was a chain driven cam - I thought it was a belt)

[JonnyH]

Apologies - just realised I posted this in the wrong section.....

[iain1067]

additonal rad looks like it's past it's best too, but then i guess you know that already, don't think it has a tensioner, the chain isn't expensive to buy but it's a **** to fit.

[JonnyH]

Yep the rad looks shot -The photo is actually a stock photo from s2central.net - it's not the car I was looking at.

[s2avant95M]

additonal rad looks like it's past it's best too, but then i guess you know that already, don't think it has a tensioner, the chain isn't expensive to buy but it's a **** to fit.

the photo is from s2central.net not the car he is looking at.

[Jamo]

Cheers everyone - thanks for the advice.

I've attached a picture (original photo courtesy of s2central.net) which shows where my untrained ears traced the rattle to. It's not like a loose heatshield, more mechanical in sound, like a rotating component which vibrates at a certain frequency. Is this where the turbo is located, or is it at the front left? Or is this the camchain - I thought that was at the front....

It's an ABY - if it is a camchain, would it likely be a case of adjusting the tensioner or would I have to get a new chain? (didn't realise it was a chain driven cam - I thought it was a belt)

The part you've highlighted is the throttle body, the chain is at the opposite end of the engine.

I have no idea why TB would rattle

[Sidspud]

You're looking at the throttle body, the idle stabalisation valve or any one of numerous hoses and bolts. It is probably just a loose connection or something that needs tightening.
If its coming from under that area then it could be the heat sheilds. Get under the car and see if they're loose.

[Chris M]

I get a rattle from that area on mine but mine is a 3B so i put it down to the dizzy, even though it had a new dizzy on 6 months before i bought it!! I'm gonna inspect the cams and valve springs when i fit the 7A exhaust cam and do the timing belt again as someone on here had the same problem/rattle and it was a broken valve spring

Cheers,

Chris