I have a Fabia 1 1.2 AZQ engine registered 2004 and I need to change the alternator. Having removed the two long screws (should these not be bolts?) I am still unable to remove the alternator as it appears to be bolted to the heat shield(?). How can I release this?

Also beneath the alternator are two wires, one red and one black which are connected to what appears to be an earthing point but none of the replacement alternators has this detail available.

If any member has done this job some advice would be welcome?

@AlandLyn

 

1. Your thread title gives no clue as to the nature of your query.
2. An alternator for a 2004 Skoda will have the red and black control wire connections.

Hi AlandLyn, welcome to the forum. 

Why do you need to change the alternator? How many miles has the car done?

 

I've not actually removed the alternator from our AZQ, but I was in that area recently, so may be able to help. 

The "red and black control wires" that Ken refers to are a blue and brown pair on the two way connector that you will have unplugged already I expect, so I don't know what the red and black ones you've encountered are, does the car have A/C?  If you haven't already done so, do disconnect battery negative, or remove the leftmost of the strip fuses above the battery before undoing the B+ main output terminal of the alternator. (But that will be much easier once you've part-extracted the alt).

 

The two long screws go into threaded bushes at the back of the alternator, so that's normal, no nuts.  Those bushes can be damn tight to pull free, so that may be all that's stopping it.

There is an M5 stud/pillar with a nut on the inside of the heatshield but I'm not sure whether it comes off the alternator or not, I've put an arrow on my picture of the back end of a spare alt indicating where the stud may fix into the alternator. Try undoing that nut, and pulling/bending the heatshield in off the stud towards the cat, and see if that sorts it for you.

 

Some pics:

 

 

 

 

 

 

 

Edited 18 July, 20187 yr by Wino

Hi,

Many thanks for your replies, for your information the car has only 51K on the clock so alternator should not be a problem. However I can never get more than 80% of charge on the battery (52 Ah) even after a long (100miles) run so something is wrong with the charging. There are a pair of thin wires which appear to be a red and a black connected to the bottom of the alternator with a covered bolt and are possible earths (?).

Yes the car has has A/C.

Not impressed by the two long screws as after 50 years in engineering bolts would have been a better solution, my opinion only!

Finally, I cannot get access to the 5mm bolt on the bottom of the heat shield as this appears to have been pop-rivetted to the engine somehow.

Reluctant to admit this but possibly a job for my local garage - at my age, late 79 not too keen on crawling about under cars any more. Never had this problem with either my Golf or Felicia.

Does the battery light illuminate when you turn the key to 'ignition on' position, before starting?

Have you checked and cleaned any earth connections near the battery?

What voltage are you seeing across the battery terminals before and after starting the engine.

How are you judging the "80% charge"?

Are these red and black wires connected together, to the same point?

 

I think it's very unlikely to be a fault with the alternator itself.

Edited 19 July, 20187 yr by Wino

The battery is new, i.e. six months old and has been tested and proved OK. There is no corrosion on any of the battery terminals or any of the associated earth or connections in the battery box.

Voltage before starting across the battery terminals is 12.52 Volts which equates to some 82% of full charge. After a long run and having left the battery to settle down over night the voltage never goes above 12.55 volts. A fully charged battery should be 12.66 Volts.

There is no drain on the battery worth speaking about merely a few milliamps which the on-board computer draws. My son is a time-served electrician and I used his professional multimeter.

After starting the engine the voltage will rise to 14.3 Volts with no load. With a full load i.e all components, rear windscreen heater, air blower, head-  side- and fog- lights etc., the voltage will drop to about 13.8 or 13.9 volts.

The red and black wires under the alternator are connected to a common point - I cannot take a photo as there is no room to position the camera.

During the last Winter I had trouble in maintaining a decent battery voltage after short runs of three or four miles, which would often drop to 12.1 or 12.2 Volts (30% to 40%) and would need a booster battery to start the engine.

I have tried substituting the battery for another with the same result so have come to the conclusion that it must be the alternator i.e. brush(es) or slip ring(s).

 

Edited 19 July, 20187 yr by AlandLyn

Disconnect, clean and reconnect the (main engine, and alternator) earth wire that comes off the top mounting of the starter motor. I think you'll see an improvement in charging voltages then.

 

You really need to disconnect the battery from the car for a few hours to get a true state of charge type voltage measurement.

 

Battery light action at ignition on?

OK. I'll give that a try.

Battery warning light - no problems. On when it should be ditto off.

A good way of working out whether the alternator is at fault, or merely wiring/connections are excessively lossy, is to look at the voltage measured locally at alternator output terminal relative to a scratched clean part of its case. Compare this reading to that across the battery terminals at a given load and (engine) temperature.

 

If there is a big difference you can then establish whether the worst of the losses are in the positive or earth connections by by measuring the drop on each, end to end whilst same conditions exist.

Quote

After starting the engine the voltage will rise to 14.3 Volts with no load. With a full load i.e all components, rear windscreen heater, air blower, head-  side- and fog- lights etc., the voltage will drop to about 13.8 or 13.9 volts

That sounds like a healthy alternator to me. It would be worth going over all the main heavy wire connections, lives and earths. Don't just look at them. Remove and clean each one. Then reattach and seal. It's not a bad idea to do this now and then even if you are not having problems. Then follow the instructions above.

I have had cars in the past that would be envious of your alternators output!

Edited 19 July, 20187 yr by LB123

Hi Guys,

Many thanks for all the suggestions. I'm afraid to say that your suggestion of taking the voltage value at the positive terminal of the alternator did not improve things - the value there was identical to other places along the circuit as well as the positive battery terminal.

Now, let me give you some history of this problem. I purchased this vehicle two years ago and most things seemed OK apart from a couple of tyres and the front brake discs which were a bit "iffy". Some weeks later the window regulator on the passenger side failed so I replaced this. No problem - but after a few operations the battery would not turn the starter motor. Jump start necessary. The battery fitted was a 36Ah of unknown make so replaced by a Cadmium of 52Ah which was the recommended size for this car. Spring of 2015 after going to a show in Bournemouth some 30 miles away the starter motor was very reluctant to turn the engine over but did manage eventually. Summer 2016 we went on holiday to West Wales and the morning we left to come home the car needed a jump start to get going. Last Winter my wife drove to the shops one morning and had to call out the breakdown service to get going again. A few days later the same thing happened and the breakdown service driver told her she needed a new battery. Fortunately she brought the old one home with her and after charging it tested OK. This battery is now in the boot for emergencies. I do not want another Winter like this again. I am still of the opinion that the alternator is at fault - plenty of Voltage but not enough Amperage. My son, the electrician agrees with me on this so the car will be going in to have the alternator checked over when the weather starts to get cold again. Incidentally my Felicia had an alternator failure in France in 2003 when the diode(s) in the voltage rectifier went belly up and was kicking out 24 volts on tickover (don't know what it was reading at 3000 RPM) and blew up the battery which cost me £1100 in spite of having RAC full cover. Some recompense from Skoda was eventually obtained after a lot of argument. So that's it, and once again, many thanks for all of the suggestions!

Edited 22 July, 20187 yr by AlandLyn

Please let us know the final outcome.

Maybe a couple or so of stupid comments:- I thought that the plan was to check the alternator output locally, if you only checked the + side locally any resistance on the earth side alternator to battery terminal/body would get missed.

Old battery, okay so it can be lifted up to a full charge voltage, but can/could it hand over the current under demand, best to load check batteries before keeping them as back up.

Alternator output, if you suspect that this is low all the time, why not start the car connect a voltmeter and apply a load via the full beam headlights and heated rear window - at maybe 2000>2500RPM does the voltage hold up?

More info:- I had a VAG tech check over the car and the results are as follows - the Terminal 30 voltage was 12.21 V on the battery while the charging voltage was 13.3 V under no load and which dropped to 13.15 with the headlights and rear windscreen heater switched on.

All of the terminals had been cleaned prior to this, and a resistance check gave a maximum total value of 0.2 Ohms. This was battery negative to earth and positive to alternator output terminal. My opinion - I still suspect the alternator!

After three days of charging the battery (Lead) and resting for a day the voltage is 12.82 Volts. Nothing wrong there.

So no more clues about the extra wires on the alternator from the VAG tech?

 

 

 

 

 

55 minutes ago, AlandLyn said:

More info:- I had a VAG tech check over the car and the results are as follows - the Terminal 30 voltage was 12.21 V on the battery while the charging voltage was 13.3 V under no load and which dropped to 13.15 with the headlights and rear windscreen heater switched on.

All of the terminals had been cleaned prior to this, and a resistance check gave a maximum total value of 0.2 Ohms. This was battery negative to earth and positive to alternator output terminal. My opinion - I still suspect the alternator!

After three days of charging the battery (Lead) and resting for a day the voltage is 12.82 Volts. Nothing wrong there.

All of which makes me suspect the regulator rather than the alternator. I suggest contacting a specialist auto electrician with the above data.