hey guys i've got a metallic rattle when driving not idle, took serpentine belt off checked pulleys all seem ok but alternator pulley made noise when spun back by hand,could this be problem.

Then 2nite picked wife up from work and temp gauge was at quarter then shot straight to half then back again and fluctuated quite a lot.

car done 82k

cambelt done at ****head stealers at lincoln by previous owner at 60k don't know about waterpump etc

any help/advice greatfully recieved.

thanks again

Check the paperwork and see if the water pump was changed. The trouble is, that if it's done at a dealer, they fit the same rubbish with the plastic impellor as was fitted originally.

If you have strange noises and temprature fluctuations, look at the pump very carefully. The impellors come loose on the shaft and break up. If a broken impellor jams the pump shaft, the cambelt comes off....

rotodiesel.

If you have strange noises and temprature fluctuations, look at the pump very carefully. The impellors come loose on the shaft and break up. If a broken impellor jams the pump shaft, the cambelt comes off....

rotodiesel.

Oh er Mrs.........

Check the paperwork and see if the water pump was changed. The trouble is, that if it's done at a dealer, they fit the same rubbish with the plastic impellor as was fitted originally.

If you have strange noises and temprature fluctuations, look at the pump very carefully. The impellors come loose on the shaft and break up. If a broken impellor jams the pump shaft, the cambelt comes off....

rotodiesel.

Blimey - are the PD140's the same????? :eek: Don't think I'll sleep at night thinking about me impeller disintegrating!!!

it does not say in the paperwork its just stamped in the service book that the belt was changed .

could the fluctuations be due to a faulty sender?

the car is not overheating ,would this not be a problem if the pump was breaking up due to lack of water circulation.

many thanks.

The problem could be due to a faulty sender but that wouldn't account for the noise. Knowing that OE VAG water pumps are a weakness makes me suspicious if you have both the noise and temperature fluctuations. If the sender is faulty, you don't know if the car is really overheating or not.

The last dud VAG water pump I saw on a PD diesel had a loose impellor. The car operated normally until you put your foot down. It then got very hot, very quickly.

rotodiesel.

i've had another look and i am 99.9% sure that the noise is the alternator pulley. got a parts store next to me work and he has a alternator on the shelf and says i can try it or return it if it not that(no charge of course , very nice chap he is at that)

wife went down motorway and said car ran perfect no overheating at speed. temp only fluctuated briefly after 4-5 mins running from cold start then gauge reads straight up and never moves.

many thanks

The alternator pulleys with a one-way drive are another VAG weakness. If you have an opportunity to try another alternator, try this first - it's dead easy to get to. Remember to disconnect the battery (be aware of the implications of doing this) as the alternator output terminal is live.

What mileage has your Superb done?

rotodiesel.

What mileage has your Superb done?

rotodiesel.

Says that it has done 82k in the first post....

Must remember not to do things in a hurry. From the various VW forums, 80k is about the average life for these one way drives. It's well worth keeping an eye on the alternator pulleys on these cars as they occasionally come apart. This does not improve the fan or the radiator...

rotodiesel.

gonna try the alternator in the morning after work so i'll let you know the outcome.

thankyou.

again.

just fitted new alternator this morning and the pulley on the old unit was well knackered but noise has not completely gone but it is about 80% better. Could any of the other pulleys be at fault aswell.

it only makes the noise if you are in say third gear going steady or slowing down coming of the gas and you have to have the window down to be able to here it. i'm a bit stumped now? anybody got any more ideas please.

Check the bearing of the alternator/PAS idler (tensioner). These tend to fail if other defects in the drive such as a faulty alternator pulley give them a hard time.

rotodiesel.

Yep I would go with the pulley tensioner on the bottom....replaced mine and my alternator pulley some time back and all is OK now!!

i'll try replacing that to see if it cures the problem then.

is it a genuine part or can you get non genuine.

i think all the flippin problems are coming at once.

could the viscous fan coupling make a noise because i think this is on the way out, it does not seem to spin as fast as my friends passat tdi 130 and you can stop it spinning quite easy but you cannot on the passat.

many thanks

Alternator pulleys are vry common on this engine.

They have a clutch in them so they only operate in one direction. This stops the pulley coming loose when the engine is stopped (as the compression of a diesel engine actually rocks it backwards before it stops).

The pulley is available seperately and is easily checked on car. If you insert a screwdriver into the alternator and gently try and turn the blades of the internal fan. It should rotate in one direction, if it doesnt move either way then its seized. Usually a seized pulley will make the ribbed belt tensioner jump around and this causes a noise.

i've just replaced the alternator coz i was told that the pulley was not available as a seperate item .

the tensioner does move a little but not a lot

Pulleys are available seperately and are modidied due to this fault.

bit late now

I'd be complaining personally.

Lummox, I used to design automotive alternators. The one way alternator clutch is fitted to prevent torsional oscillations from the crankshaft overstressing the drive.

Torsional crankshaft oscillation is a serious problem on any diesel (which is why they all have a TV damper built into the crank pulley) and these oscillations are magnified by the high drive ratio to the alternator pulley. The diesel has a smaller speed range between idle and max than a petrol engine, thus a higher drive ratio can be used without any danger of overspeeding the alternator. This higher ratio coupled with the oscillation makes the problem much worse on a diesel compared with a petrol engine.

The one way drives are not reliable in general but on the VAG NS power unit, they can damage the fan and the radiator if they come apart. It's wise to keep an eye on the condition of the alternator pulley - 80k miles is good going.

rotodiesel.

Fair enough, all I know is the Alhambra ones used to fall off after coming loose.

thanks guys but we seem to have got lost in the middle somewhere.

i've got a metallic rattle from somewhere.

i have replaced the alternator and pulley and checked all the other pulleys and they seem fine no noise no play.

noise now really doin me head in.

engine undershield was loose but that is now refastened still no joy.

dont no if this has anything to do with it but when i pulled away from traffic lights today a couple of the dash lights flashed ie: abs asr beep went of a couple of times then battery light flashed very briefly then all was fine.

checked charging and that was fine.

cannot afford to break down going on holiday on sat with young familly on board gonna drive about 2500 miles.

please help.

anyone know of a good specialist not a stealer if poss in the scunthorpe area.

many thanks

Does the noise occur if the a/c is switch off?

i'm sure it does but i'll get the wife to listen when she goes to work in a minute.

i did check the a/c fan it spins freely by hand theres no play and its quiet