Ahu Engine Noise

[seatkid]

My vehicle is a MK1 late 98 AHU 90 bhp diesel, 120k

 

Over the last year or so been getting a "thats never been there before" noise from my engine thats getting louder by the month. It's engine speed related, definitley something on the engine itself, not transmission etc. Most noticeable at around 2000 rpm - it gets louder with engine revs but gets drowned out at higher engine speeds. I can hear it in the cabin as well as under the bonnet.

 

Description: Sounds like a shot or dry bearing noise with a lot of random chatter thrown in - definitely not a healthy sound, like something could fall to bits soon! Its a white noise kind of sound and not a whining, groaning or other frequency/tonal type noise.

 

Location: Difficult to pin down but seems significantly louder from the back of the engine.

 

Could it be:

 

1. Water pump - do the bearings ever get noisy without loss of water etc?

 

2. Aux belt tensioner - doesnt seem to be from that area though.

 

3. Is there a (replacable) idler roller in addition to the tensioner on the cambelt? I'm not sure if that was replaced when the cambelt was changed at 75k

 

4. Can the EGR valve make strange noises?

 

I'm fairly sure its not the alternator, power steering pump or a/c pulley. When the engine is switched off (hot) I can hear the usual faint whistle of the turbo winding down smoothly so I dont think theres anything wrong with the turbo.

 

Any comments appreciated!

[gregers]

does the noise get worse when the aircon is switched on?

surprised your asking,your normally answering the questions m8.

this must have YOU stumped.

[seatkid]

does the noise get worse when the aircon is switched on?

Not that am I aware of, the a/c is a bit noisy as its running low on gas and that drowns out the noise.

 

Not sure if its related, but for a couple of years, when the engine is lukewarm, as I accelerate hard, there is is a loud shhhhh as I go through a certain rev band (around 1900-2500rpm IIRC) peaking and dies down as the revs increase - which is why asked about the EGR valve. Its not there cold or hot though and only noticeable when I floor the throttle.

Edited April 30, 2012 by seatkid

[alan_131]

If it helps at all my r plate 90 used to make the shhh noise you describe or something very like it. 100k when i got it. From inside cabin sounds like it's coming from left of dash possibly because thats where the pollen filter is? My first turbo and I always assumed it was waste gate dumping. Don't recall noticing it being temp related but took forever to warm up. Went away when the performance dropped off... up to 162k and still working ok apart from some odd noises from power steering pump area. Fractured bracket vibing at low revs so if its the same shushing noise and thats the cause of your noise you might havey got a bit of breathing space. Btw i found isolators on engine cover shot and cover chewing thru pipes occ audible.....good luck

[seatkid]

Thanks for the replies so far.

 

It was suggested to me by a local indy today (working from my description and not actually hearing it) that its probably the one way clutch on the alternator.

 

However, I thought the one-way clutch was only fitted to Mk2 PD engined cars. Am I right? :unsure:

 

He quoted around £50 for the clutch pulley and another £50 labour to change plus VAT, :o :lol: :lol: :lol:

Edited May 1, 2012 by seatkid

[gregers]

well iirc the price for the pully is about right,but im sure YOUR quite capable in changing it your self?

if you do i would sugest changing the tensioner aswell.

[seatkid]

Do I detect just a little :lol: Gregs?? :o :lol: I'm getting a little too old and tired for this DIY lark. Looking for easy options, only problem is that a lot of problems with my cars in the past started after going to a garage for "repairs". :unsure:

 

Just checked, my 120A alternator 0123515014 does not have a one way clutch so eliminating that possibility! :lol:

 

(BTW a brand new alternator costs £124....)

Edited May 1, 2012 by seatkid

[gregers]

Just checked, my 120A alternator 0123515014 does not have a one way clutch so eliminating that possibility! :unsure:

well thats good then.

i wasnt being sarky m8,just know how you are from the forum,but if as you say your getting OLD then i can see your reasoning.

 

re reading your 1st post about noise,does it remind you of the aircon pulley noise?

read up on it and see if it is??

Edited May 1, 2012 by gregers

[Bigjeeze]

Check out the aux belt tensioner - that is relatively cheap and quite likely..

[seatkid]

Thanks lads. No offence Gregs, just me having a dig at myself, seems no-one understands my sense of humour - especially my wife!! :unsure:

 

Will be reading up on your suggestions over the next few days.

[chrispb123456]

Hi Seatkid

Why not temporarily remove PAS belt and auxiliary drive belts then run engine, that will eliminate those if the noise is still there.

[bigdave982]

I had a funny rattling noise on my mk1 once,increased with revs till engine noise drowned it out. Seemed to be coming fron drive belt areas. Turned out to be one of the alternator mounting bolts had come loose and the bolt head was rattling against one of the belt pulleys,cant recall which one tho,it was a long bolt that I can remember

[gregers]

heat sheild???????????

 

Thanks lads. No offence Gregs, just me having a dig at myself, seems no-one understands my sense of humour - especially my wife!! :unsure:

 

HUMOUR oh ok if you say so :lol:

[billywizzo]

My old MK1 had a rattling that turned out to be the air-con pulley failing.

After a while it seized snapping the belt.

It was only once it seized that I worked out what it was as I could not turn the pulley.

I know you don't think it is a pulley but you need to take the belt off to check them.

 

Bill

[seatkid]

Again, thanks for all the comments, I'll take up Chris's logical suggestion and try it without the belts, but it'll have to wait until we get a decent spell of weather combined with some spare time, a good mood and not having to look after the grandkids. (It may be some time :huh: )

 

I'll post my findings - who knows - I might even make a "How to Change Aux/PAS Belts guide" :rolleyes:

[seatkid]

UPDATE:

 

Nice weathers duped me into having a go. It was scary the amount of tension the roller has on the belt, no way just a screwdriver leverage job to lift it, I ended putting a 13 mm ring spanner on the tensioner roller securing bolt and improvised an extension with a long torque wrench (theres not enough room for a socket on the bolt). After the bolt tightening a fair bit finally released the belt and then let the tensioner go down to its vertical position and removed the roller.

 

The alternator and a/c pulley are both sweet and quiet. THe roller makes the kind of noise I'm hearing if I spin the centre whilst holding the roller, but is a lot quieter when holding the centre and spinning the roller. Also a fair bit of play in the bearing so hopefully this is the culprit.

 

Tomorrow i'll get a new roller from GSF (£22) but has anyone got any tips how I should lever the darned tensioner back up so I can get the belt on. I could use the bolt method again, but that will involve putting a lot of stress on the roller bearing as the bolt will tighten up.

 

I somehow feel I'm doing something wrong....

 

Eeek! :D just found this

 

 

I would have guessed a special tool was involved.

 

Any ideas folks?

Edited May 27, 2012 by seatkid

[octo0072000]

did mine with a pair of mole-grips and a long socket on a extension bar

it's a PITA to get the belt back on mine being auto as well

the roller on mine has some wear on it bearing is ok but the plastic roller is worn looks like it's glued to the bearing so but a bit of bearing seal on the edges so it ran into edge of the roller left over night seems solid now

also my 110bhp 2000 mk1 has the over run clutch on the alternator

Edited May 28, 2012 by octo0072000

[seatkid]

GSF Car Parts are getting me a Laser 4948 Tensioning tool (

[octo0072000]

GSF Car Parts are getting me a Laser 4948 Tensioning tool (

[seatkid]

GSF Car Parts are getting me a Laser 4948 Tensioning tool (

[bigdave982]

If its the aux belt tensioner wheel u are changing,all i did to releive the tensioner was slip a big adjustable spanner over the arm and relieve the belt tension that way

[octo0072000]

iv's still got a piston wind back tool

made for a old 2,9 Granada trouble is finding it it's in the shed somewhere don't get me wrong i like the right tools too

[seatkid]

If its the aux belt tensioner wheel u are changing,all i did to releive the tensioner was slip a big adjustable spanner over the arm and relieve the belt tension that way

Thought about that but knowing my luck it would slip off and lots of swearing, blood, bruised knuckles would follow!! :rolleyes: Anyway the new tool makes changing the aux belt a cinch :)

 

The new roller makes the old roller look clapped out so I thought it must be this.

 

Starts car up, initially sweet, revs the car up and....doh!...the noise is still there!! :angry:

 

So using the ear to screwdriver technique, it seems a lot of noise is coming off the tensioner spring housing.....and looking at the roller I notice its almost fully in the vertical position. Looks as if the belt is stretched and maybe the tensioner is at or near the hard limit. So it's off with the belt tomorrow and down to GSF to compare it against a new one.

[octo0072000]

Seatkid

alot of what you describe could be clutch related do you get the noise with your foot on the clutch not sure on mk1 is it dual mass flywheel just a thought

if you move the cam belt cover out a bit there is a roller on the top of mine buy mine is a 110bhp auto reg 2000 i tried to pm you but say you can.t recieve pms??

[seatkid]

Seatkid

alot of what you describe could be clutch related do you get the noise with your foot on the clutch not sure on mk1 is it dual mass flywheel just a thought

if you move the cam belt cover out a bit there is a roller on the top of mine buy mine is a 110bhp auto reg 2000 i tried to pm you but say you can.t recieve pms??

Definitely not clutch. No DMF on my 90bhp, 110bhp does have DMF and one way clutched alternator.

 

frightened it might be idler roller on cambelt.

 

It does sound very much as if the noise coming from aux tensioner spring housing.

 

I found the original belts [Conti 1145] (I tend to keep things like that! :rolleyes:) Tommorow will compare belt lengths and maybe swap (original belt has cracks in the ribbing so will only a temporary try out.)

 

If necessary, I will also try original suggestion of removing all belts and see if the noise disappears.

 

I don't do PMs, sorry.

Edited May 28, 2012 by seatkid