A question about alternators

[catzi]

I've got the battery/Sediment lights lit on the dashboard, indicating that the alternator is malfunctioning.

If this is the case, this will be the fourth(!) alternator to have failed in as many years. Hopefully the alternator may be replaced under warranty (if indeed it is still in warranty) but I am a bit mystified as to why the alternator may be continually failing.

I have a leisure battery fitted but, other than that, no non-standard stuff.

Thoughts on a postcard please.

[stuc]

Sounds like a regulator/rectifier problem to me causing the alternator to fail.

[g8dhe]

On the V6 its been reported that oil from leaking seals runs down and covers the alternator (as well as running back to the exhaust and creating a smell) which over time causes the alternator to overheat causing damage. That seems to have been the problem on ours as well as the mechanics reported that the alternator was covered in oil when it was refurbished after a failure.

[Simon Jones]

The regulator is built in to the alternator (although it can be replaced separately) so it would have been renewed with each replacement alternator so unless they are poor quality it sounds like it's vehicle-related problem. I think in 26 years of vehicle ownership (that's scary!) I've never needed to replace an alternator due to failure. The only one that broke was when I implanted my car into the back of a van that had better brakes than I did.

If it were me, I'd be doing some tests to see what sort of load is being put on it. Did you get any feedback from the supplier when the previous one(s) failed?

[winchman]

I would check or replace the body to engine earths and possinly the battery earth unless you have a Megga to test them properly

[catzi]

Cheers for the replies. It's booked into the garage in a week's time. I will ask if they can look at replacing the earths and check the loading. The garage owner will get it replaced under warranty if it is still in.

Half thinking about trading up as the last few garage bills have been large. Not sure whether to get another Bongo but I think I might miss it too much. Also there is the question of money (of which I have none).

[Northern Bongolow]

have a read of this link.

http://www.igmaynard.co.uk/bongo/forum/ ... ilit=90amp.

or this could cause it cook the alternator.

http://www.igmaynard.co.uk/bongo/forum/ ... ifold+stud

[g8dhe]

I seem to recall that some refurbished alternators using only 70Amp diodes tended to die after a year as well, there was a discussion on this a while ago, whilst 70Amp was supposed to be sufficient they only just lasted the warranty period......

[catzi]

Interesting stuff - I'm going to check the studs on the manifold and also ensure that the garage knows about the 90amp requirement for the alternator.

Had to drive the Bongo home from work last night - by the time I got home the lights were very dim and the speedo and rev counter had stopped working. Various lights were lit/flashing on the dash. Will need to get the battery out and give it a charge up so I can drive it to the mechanic.

Can't get it it into the garage for a week or so and will have to rough it in the meantime - never mind I'm off to Bermuda for a few days with work

[catzi]

Just thought I'd post an update.

The old alternator had actually failed mechanically. This is interesting as this happened to the last one - about 15 months ago. I had also asked the mechanic to diagnose a sort of 'rubbing sound' and it turned out it was the alternator.

My mechanic is scratching his head as to why they are failing like this but, on both them, the bearings had gone and the spindle had lots of play on it. The first one was apparently close to coming apart. He thought, with the first alternator, that the previous garage may have overtightened the belts and worn the alternator prematurely but this definitely wasn't the case for the second one.

The only thing he's noticed is that the angles on the belts are not totally straight but he can only attach the alternator to the mounting points and there is nothing else to adjust.

Thoughts on a postcard please.

[rita]

The only thing he's noticed is that the angles on the belts are not totally straight

I seem to remember that you had this problem a while ago and the compressor aligning bolt was missing,you can true the belts using this bolt.

I presume that you have had a new bolt fitted since then..

[Northern Bongolow]

on a gen mazda bongo alternator there is a top hat shaped spacer/washer that if not fitted correctly can move the mounting position in relation to the belts, copy or others may not have this.
its not shown here in the back mounting, and it hasnt got a part number etc.

http://lushprojects.com/bongopartsmk2/c ... mgno=.html

maybe fit a second hand gen bongo alternator form george. the pic shown below shows the spacer fitted in the rear mounting.

http://www.bongospares.co.uk/shop/elect ... lternator/

[Simon Jones]

Have you got the correct adjuster bolt to set the tension?