Morning All

was having my air con re-gassed yesterday in preparation for long drive through France in a couple of weeks and I noticed that when the engine was running a 'crackling' sound seemed to becoming from the alternator. Got worse as I added electrical load (lights, aircon, etc.). It was a similar sound to that of static electricity (anyone remember the van de graff generator in physics at school ?). Anyone had similar experience ? and is it terminal ?

 

Whilst £100+ is a lump out of our holiday funds, I tempted to replace the unit as a precaution as the last thing I want is a failure whilst on holiday with the family (the wife already doesn't believe that the Skoda will make it but I have every faith in it !)

 

The existing unit says 90A on the back but looking on various parts sites there are both 90A and 120A versions. The difference being that the 120A has a spec that includes A/C - Yes whilst the 90A says A/C - No which I presume means Air Conditioning ?

 

As I have air con has the wrong one been fitted in the past (and therefore the cause of the noise) and should I go for a 120A ??

 

Finally for an extra £30 would you go for a Bosch over a random brand (RTX, REMY, etc.) ?

 

'54 Reg Octavia Estate 1.9 TDi 130 6-speed manual engine code ASZ

 

Thanks

It could be the alternator pulley. At idle is the tensioner bouncing around? Also does it sound worse when you lift off the power and let the revs drop?

Sent from my D5803 using Tapatalk

yes the tensioner oscillates more when there is more electrical load on the system compared to when everything is switched off. Also, I notice that the noise stops as the revs rise past 1200rpm and returns at idle (when lights, a/c, heated window are on)

So does this suggest the pulley and can that be replaced independently of the alternator ? I think I'm going to bite the bullet and replace the alternator for peace of mind. In which case, back to my question on which one 90A or 120A and what brand ?

 

Thanks for your help

My Mk. 1 VRS just fried it's alternator.

 

Judging by what a bitch it was to remove (the steel collets were very good friends with the alloy block) and the VAG branding on it, plus it's general conditon, leaves me to believe that it was the original Bosch factory unit.

 

However, my car also has Climatronic air-con, but the alternator I removed was 90 amp. Plus the new Bosch unit supplied by TPS as the correct replacement, is also 90 amps. The only choice I was given initially over the phone was 'is it a Bosch or Valeo unit?' Nothing about amperage.

 

Don't quote me, but I am thinking that the 120 amp version might be for Diesels? They often have a higher spec alternator and battery, for the cranking power on a cold diesel motor.

 

Anyway my 90 amp replacement is all hunky dory, even with everything switched on. So I reckon that is the right one for you.

The petrol engines don't have the one way clutch on the alternator.

Sent from my D5803 using Tapatalk

yes the tensioner oscillates more when there is more electrical load on the system compared to when everything is switched off. Also, I notice that the noise stops as the revs rise past 1200rpm and returns at idle (when lights, a/c, heated window are on)

So does this suggest the pulley and can that be replaced independently of the alternator ? I think I'm going to bite the bullet and replace the alternator for peace of mind. In which case, back to my question on which one 90A or 120A and what brand ?

Thanks for your help

You may find the new alternator doesn't come with the pulley.

Sent from my D5803 using Tapatalk

yes the tensioner oscillates more when there is more electrical load on the system compared to when everything is switched off. Also, I notice that the noise stops as the revs rise past 1200rpm and returns at idle (when lights, a/c, heated window are on)

So does this suggest the pulley and can that be replaced independently of the alternator ? I think I'm going to bite the bullet and replace the alternator for peace of mind. In which case, back to my question on which one 90A or 120A and what brand ?

Thanks for your help

Just reading your post again I would expect it is the pulley, your symptoms sound like my car. I also replaced the tensioner as the duff pulley killed it. On the PD engine the tensioner should only be about £30 and the pulley about the same.

But you will need to remove the alternator to change the pulley and you need a special tool to get the pulley off.

Sent from my D5803 using Tapatalk