B4 Alternator questions

Black 1996 B4 sedan:

My B4 original Bosch alternator with date stamp 05/96 died this past weekend -- 23 years is not a bad run. In addition to replacing the alternator, I plan to also replace the stock pulley with a Made in Germany clutched pulley I have on hand that I bought some time back.

This is the clutched pulley ( I have no connection to seller) :
https://www.idparts.com/clutched-alternator-pulley-a3b4-p-3302.html

My trusted mechanic who is doing the work was not too keen on using the clutched pulley and he said he's seen them fail causing a perfectly functional alternator to not work properly.

Any experience with these pulleys? Advice and comments invited.

Mine failed but it locked up so I haven't changed it. Some day. I suppose if it started slipping the alternator wouldn't charge. Idunno what the more common failure mode is.

But if it fails it can be replaced without removing the alternator.

If the clutched pulley fails, it just becomes a non-clutched pulley, right? How is that worse than having a solid pulley?

When they lock up, they pound the bearings and eventually they blow apart... which can result in the accessory belt flying off and getting pulled underneath the timing belt cover... then you get to pull the head. Or worse. So no, it is most certainly NOT the same as a fixed pulley.

However, I would want to upgrade to the clutched type anyway to save the 1Z's fragile crank snout, upgrade to the newer style balancer pulley too. And just check the function of the alternator pulley at every service... same as you would on an ALH/BEW/BHW/etc. that use them from the factory.

I’ve read to increase alternator life, you need to run LED bulbs. You probably could have gotten 30 years out of it.

-Todd

TDIL3Dad, have a look at this thread:
https://forums.tdiclub.com/showthread.php?t=430807

You didn't say how it died. If it's not outputting the appropriate voltage, that's just the regulator or brushes on the regulator. In the past 3 months our other B4 TDI's alternator let go on the front bearing. I've been running the A4 clutched pulley on mine without issue since the difference in belt alignment between the two is minimal.

TDIL3dad said:

Black 1996 B4 sedan:

My B4 original Bosch alternator with date stamp 05/96 died this past weekend -- 23 years is not a bad run. In addition to replacing the alternator, I plan to also replace the stock pulley with a Made in Germany clutched pulley I have on hand that I bought some time back.

This is the clutched pulley ( I have no connection to seller) :
https://www.idparts.com/clutched-alternator-pulley-a3b4-p-3302.html

My trusted mechanic who is doing the work was not too keen on using the clutched pulley and he said he's seen them fail causing a perfectly functional alternator to not work properly.

Any experience with these pulleys? Advice and comments invited.

Click to expand...

You should use the clutched pulley. My Mk3 alternator lasted to about 179k miles then died. When I took it in for rebuild they said the clutched pulley had failed (locked up) and they replaced it with a new one. That alternator is currently running on the B3V and hasn't given me any signs of problems at all.

I think it's just a good idea to use one as it helps to absorb the changes in tension on the various components. I'd tell the rebuilder that you need one.

Steve

Update:

I purchased a Bosch alternator from FCP Euro to replace the dead alternator. Will also have my clutched pulley installed, and while at it replace the alternator belt at same time.

The alternator died over several days. First indication was the radio acting up, then next came the cluster needles going limp for short periods of time. Next, the trip odometer and the digital clock would zero out when I turned the ignition off.

The last gasp was while I was driving on the interstate at highway speed, all needles went limp, the radio stopped working, the digital displays all went blank and the car started losing power -- everything within a very short time. That's when I quickly moved to the shoulder and turned the engine off. The car would not start after that and had to be towed to the shop.

All if that occurred and the battery light never came on, prior to? Something isn’t right.

-Todd

Get a hold of ChubsAuto because you might have a problem with your cluster. THey can be damaged by low voltage. Details on the fix:
http://forums.tdiclub.com/showthread.php?t=268798

Again, check your voltage regulator as this is likely yout failure mode:
http://forums.tdiclub.com/showthread.php?p=2189345#post2189345
http://forums.tdiclub.com/showthread.php?p=1201686#post1201686

You have to wait for the parts to arrive, and a cheapo meter will tell you if the voltage regulator is good or not.

Cleaning your grounds might be in order too.

ToddA1 said:

All if that occurred and the battery light never came on, prior to? Something isn’t right.

-Todd

Click to expand...

No battery light other than normal ie when starting the car.
Battery itself is fairly new about a little over a year old and is the VW brand battery for diesel cars.

Did you have the alternator tested, or are you assuming it’s dead?

Grounds are clean? Factory wiring at the alternator? Does the battery light come on every time, with key on bulb check?

-Todd

The battery light won't always come on if an alternator malfunctions. If charging voltage is low, the battery light would not come on and the battery would eventually go flat. What was the charging voltage?

New alternator seems to have taken care of my electric gremlins. I've been driving the black sedan every day and no issues so far. Everything on the Chubbs GLX cluster now works consistently, the radio works, and the sunroof works.


BTW over the last 12-18 months I've installed a new OEM battery (dealer had them on sale - these are the batteries VW uses or used on diesels), a new starter, a new OEM compressor, and now a Bosch alternator, and added the clutched pulley.

I should not have any problems with mysterious electric gremlins -- I hope.