You are here:

Land Rover Repair/96 disco I alternator


QUESTION: My disco I has eaten 6 alternators in less than a year. I have replaced the belt, the battery output is 12.8v, the tensioner and pulley are working good. The vehicle runs well and everything works fine until the alt. goes. When it does I begin hearing a whining sound higher pitched with rpms then shortly after that sound is heard (like 50 miles) the alternator goes out. One even caught fire after it burned out from friction I guess.
What in the heck is going on?

ANSWER: There are three possible explanations:  Without seeing your truck it's impossible to say which applies to you though I will say #3 is the most common scenario among trucks that come to Robison Service

1 - You are installing the alternator wrong.  I have had trucks come in to Robison Service with alternator belts misrouted so they did not work, and wires left off.
2 - There could be an underlying problem in the car.  About the only thing that would lead to repeat failure is an intermittent open circuit in one of the wires (See possibility #!)
4 - The most likely answer is that you have installed one junk rebuild after another.  Most of the time, when I hear stories like this, people are buying consumer discount store alternators and indeed the quality of some of those is just abysmal.  If that is the case for you get a name brand unit - a Bosch or genuine Land Rover and that should be the end of your trouble

---------- FOLLOW-UP ----------

QUESTION: Thank you so much for responding. Well you are correct in assuming that I have installed one junk rebuild after another @$195.00 but with a life time warranty that they are no longer willing to honor,the alternators are from Auto Zone, however they have all failed for the same reason the original Bosch failed (installed by previous owner)although it worked far longer than any others. I have checked and rechecked the belt feed it is correct, I have done it enough times I can do it in my sleep.
There are only three wires and no mistaking where they go as one is obviously the battery wire being the largest,the other has a push on flat connector or spade for the tach. and the third goes on the only pole left.
My concern is that there is an open circuit somewhere and I don't know how to find it. I am going to try to put a new voltage regulator in the Bosch unit but after that I am out of guesses. Any suggestions?

ANSWER: You would have to make sure the connection on the heavy red wire is good at the fusebox or distribution block.  Otherwise I suggest biting the bullet and buying a good alternator and learning from that experience that junk parts are just that . . junk

---------- FOLLOW-UP ----------

QUESTION: I live on disability so unfortunately cannot afford to purchase a $300 - 400 alternator to risk it going up in smoke with the others as I said the Bosch unit failed as well so I am not inclined to believe that spending more money is the answer to the problem. I will check the connections on the heavy red wire are good at the fuse block. If you should have any other ideas please feel free to send me an e-mail to .
Thank for your assistance and suggestions they are much appreciated.
Know anyone who would like to buy this piece of crap, $1400 takes it. It is otherwise a good vehicle as I have fixed all the other land rover short falls & problems and there were a bunch.

The only thing that would make the alternator go up in smoke would be a short on the output cable and if that were the case none of the alternators would have ever worked.  The fact that they worked for a while (or so you indicated) tells me you are probably installing one bad one after another but there is a possibility of cable problems.  You can buy an electrical manual from Atlantic British or Rovers North, or subscribe to the factory site online and manually follow and test the alternator wires.  There is not much to test or find wrong there.  However, that is your next step if you believe the car is killing the alternators.

Land Rover Repair

All Answers

Answers by Expert:

Ask Experts


John Elder Robison


I own J E Robison Service in Springfield, MA. We are Bosch Car Service for Land Rover, BMW, Mercedes, and other European lines. I can answer most questions about Land Rover service or repair. I'm known as a car enthusiast, machine aficianado, photographer, writer, and speaker. I've been around Land Rovers and British cars most of my life. Visit me at my car business, or my author website, Check out my autism and writing blog at or my photos on John Elder Robison


I have been a Land Rover service manager since Land Rover returned to North America in 1987. My company is a four-star Bosch Car Service facility, known nationwide for Land Rover service, overhaul, customization, and restoration. In addition to Land Rover our company services BMW, Jaguar, Mercedes-Benz, Rolls_Royce, and Bentley motorcars. We have factory-plus-level service capability for all makes. Visit my company online at > service > land rover Also visit my blog at


In the Land Rover world, my writing can be found in various print magazines and online at robisonservice.blogspot,com. In the wider publishing world, my work is published by 20 publishers in over 50 countries. Mt books Look Me in the Eye, Be Different and Raising Cubby have made US and international bestseller lists.

I am ASE certified, Bosch Trained, and trained by Omnitec/T4 and Autologic on their Land Rover test systems.

©2017 All rights reserved.