I have a 2003 Discovery 39C. 330hp Cat. The unit has 17,000 miles on it and I just put the third alternator in it. Is anyone else experiencing this?

Has anyone actually examined the "defective" units to determine what aspect of the alternators had failed.I have seen numerous units replaced that only required four dollars worth of brushes to return it to service!This is unlikely the case in your case due to the low mileage,but the principle is the same.The alternator is composed of many parts that each has a function and some external factor may be causing the high failure rate.

I have an '03 Bounder with a Cummins ISB and had to replace my alternator at 20K on the mileage. $450 for the replacement. Technician disassembled at my request. The diode was cracked/broken and had caused the unit to cease operation. I have heard from others of the exact same problem.

Diode failure is the most common alternator problem and can easily be rebuilt in an alternator shop. Most dealers simply replace the alternator with a rebuilt, but you could remove it yourself and take it to motor/alternator shop and save a lot.

As to why you suffered three failures in 5 years, it is hard to say. If it is diodes or windings, it could be moisture problems, which could stem from relative lack of use. If it is mechanical failure it could be a misaligned pully or too much tension on the drive belt. Without knowing the nature of the failure it is all guesswork.

quote:

Originally posted by Bounderoo:
I have an '03 Bounder with a Cummins ISB and had to replace my alternator at 20K on the mileage. $450 for the replacement. Technician disassembled at my request. The diode was cracked/broken and had caused the unit to cease operation. I have heard from others of the exact same problem.

I would hope that you were able to pay the core charge and take the alternator with you since the failed diodes constitute a relatively insignificant fault.When you get to a place where you can get it repaired,the result will be an inexpensive spare to have on hand.