230 TE - Engine Rattle

[Ade]

I have a horrible rattling sound from the engine compartment at low revs like the rattling of an exhuast sheild which disappears as the engine is revved. Investigation points to the alternator being noisy (knackered bearing?). Replacing the alternator looks like costing £100+ which a lot of money if it proves not to be the alternator. Anybody know where I can get a reasonably priced alternator or has anybody managed to replace the bearing themselves? If so where do you get the bearing from?

Trouble is the alternator works perfectly

 

[Spike]

If its a rattle at low revs, i'd be more inclined to check the belt tensioner shock absorber which tend to go at about 100k and make the sound that you describe.... in fact judging by your description, I'd put money on it being the little blighter.

Not too exbenzive to replace but a little bit fiddly to get at.

 

[Ade]

Thanks Spike, I'll try that and let you know the outcome.

 

[flyingtech55]

Engine rattle

If you want eliminate the alternator, you could remove the drive belt and run the engine BRIEFLY. This will remove the guesswork and save you £100 (at least) if the alternator is innocent. Just make the oil pump isn't driven by the drive belt (I'm pretty sure it's OK though.) However, I would lay odds that Spike is right.

 

[Ade]

Flyingtechh 55. Good tip, Thanks

 

[Ade]

Hi Chaps

Changed the Drive belt tensioner damper over the weekend and it has certainly improved the situation (mounting rubbers of the damper completely shot) so thanks for the advice. Had to remove the complete tensioner however to get the damper off (Usual - supertight bolt!), took about 4 hours in total with a bit of headscratching and a quick lunch inbetween.

Damper cost less than £22 (vat NOT included) from the local robbers.

However, having now eliminated the annoying 'loose' rattle I'm now left with a more 'Notchy' 'ratcheting' type of rattling noise from the engine which occurs when the car first pulls away but disappears as the car gets up to speed. This noise started around the same time as the damper rattle but was masked by the noise of it.

Any ideas on what this could be would be welcomed!

 

[andy_k]

have you checked the exhaust brackets?

just rear of the downpipe there is a clamp - 99% of them fall apart and create the rattling sound you are describing

HTH

Andy K

 

[Ade]

Andy

I'll give it a look tonight. Is this the clamp that sits on the horizontal? Is this usually a new clamp or just new bolts?

Ade

 

[NormanB]

Ade

I did not catch the age and mileage of your car and I do not want to send you on a wild goose chase.

While you are examining the exhaust clamp you may also like to check your engine mounts. If your vehicle is elderly (like mine :wink: ) they must be suspect when rattles, noise, vibrations start to occur.

Unfortunately they fail in such a way that the engine will actually drop in height too which cause problems on alignment of umbilicals (like the exhaust) as well as transmitted vibes throught the body structure - often the only sure fire way of checking is to remove and compare to new. They are not expensive but are labour intensive to replace - probably same difficulty level as the job you just did on the tensioner.

Good luck and let us know how you get on.

 

[Ade]

Norman

Thanks for the thought. When changing the damper I did notice a slight 'wobble' of the engine making me momentarily think about the engine mounts but being immersed in the problem of the damper I thought no more of it. However I will take the time to check the mounts and let you know.

The beast is a J Reg 1991 and has done 123K miles so the engine mounts could also help 'tighten' up the rattily bits!

Ade

 

[Ade]

Andy_K/Norman B

Exhaust Bracket fine, more tappet noise than anything but not convinced.

Engine mounts not too bad but I'll change them anyway

 

[Ade]

Could the ratcheting, notchy noise be the tappets? Not so much on idle but when engine put initially under strain when pulling away? Thinking oil pressure to Hydraulic lifters?

Timing chain tensioner ever need replacing?

 

[andy_k]

tappets you'll hear at idle (or at least that's my experience) and particularly until the engine gets warmed up - lower oil pressure and slightly higher viscosity can starve them of oil - if that's what it is you have to decide whether or not they are worth doing - i've got one slightly noisy one and I'm leaving things alone until it gets worse

You can normally listen to them and see where the noise is coming from - the very keen ones will use a stethoscope but a socket extension or large screwdriver placed against the rocker cover and then pressed against your ear will give you a pretty good idea of the culprit(s)

Timing chain tensioner/guide can need replacing but that will be a constant rattle which is particularly apparent at start up and more importantly will clearly be audible at the very front of the engine.


HTH

Andy

 

[NormanB]

Oh and another thing...................

A leaky exhaust at the cylinder head/exhaust manifold joint can make a similar nosie funnily enough - I know this from experience - as it warmed up it sealed and noise reduced.

Just in passing. :wink:

 

[NormanB]

duplicate posting edited out - do not know how that happened

 

[Ade]

Thanks for your help guys

When I tried using the old screw driver technique a couple of weeks ago it suggested the alternator was the problem (knackered bearings?) although it works fine. Flyingtech55 suggested removing the drivebelt to run for a second or two to see if noise dissappears which I've yet to try (limited time) but the noise is more from the front of the engine than rear, hence Spike's suggestion of the drivebelt tensioner damper (which upon changing although didn't cure the noise entirely but certainly helped). However I'm not convinced about the alternator.

As for the exhaust a point worth noting but it still makes the noise after pulling away from standstill after a long run on the motorway. Mountings all seem secure.

The noise is really irritating at pullaway and although the engine is ever so slightly lumpy at idle (good service needed?) when underway the car feels as smooth as silk which is why I'm so perplexed. I'd expect tappet noise almost constantly unless they smooth out at higher revs. Doesn't do it at idle either only when revving at standstill and then passes as revs increase (rattle). Notchy ratcheting sound only at intial pull away not revving at idle.

Its the same old story of time. I just don't seem to have enough of it to go out and do some serious tinkering and 'Play' with my baby And money- Either got the money and no time or time and dealers not open etc etc. Maybe a good indy can sort it?). My gut instinct is that this is a really silly thing that once discovered everybody will think 'Ah! I will remember that one!).

I'll keep you posted.

 

[Grumpy]

I bet it's the engine mounts. Jack up the front of the car, take off the under tray and compare the engine mounts one side to the other. You might find that the cover plate over the top of one of the mounts is lower than the other. The mounts are called ?hydro mounts? as the contain a liquid. This tends to leak away over time. They are fairly easy to change. When I changed mine I found a web site with full instructions and photographs!! I can?t find it now. There are only 2. One on each side. There is no need to change the rear mount under the transmission. Jack up the car on stands at the front. The jack up the engine with a block of wood between the jack and the sump. Undo the bolts at the top and bottom of a mount on one side. Replace this mount and then do the other side. 2 hours max.
You will not believe the difference!! It?s like a new car. All those odd noises when sat at lights in drive and first thing at start up are gone. It doesn?t clonk when you put it in drive and all for £26.00 and 2 hours work :lol:

 

[Ade]

Grumpy

Thanks! NormanB also suggested engine mounts but the way you descibe 'all those odd noises' and the 'clonk when you put it in drive' the sounds just like mine!

I'm on this for the weekend to see if it works and will keep you posted.

Ade

PS My local stealer tells me the mounts are £50each + VAT! How long ago did you do them and where did you get the mounts?

I have A/C which I believe was retro fitted but as an approved Mercedes kit.

There are several listing in the Europarts Catalogue for models with A/C and for models without A/C.

As my car has retrofitted A/C, is it non A/C as far as ordering the mounts goes or were the mounts changed when the A/C was fitted thus being officially now A/C?

What is the difference in the mounts and why? Any ideas?

Ade