99 land rover d2 153k. Issue, battery light came on, revved up engine and it went off. came on again and tried revving engine and it did not go off. was driving home and radio shut off, rover got sluggish, gauges went haywire. took battery and had it tested... tested ok. took off alternator and it tested ok. had battery charged and put it all back together and it started fine with no battery light. after reading many forums, i am worried that it is going to happen again. what is wrong?? with it. don't want to be caught driving and have it die again.

 

Just to be clear, I still need to know what you guys think is wrong, I did not do anything to fix the problem. The only reason it seems to be working right now is because I have a fully charged battery. Thanks.

 

You need to take your truck to a local parts store and have them test the complete battery/alternator system together, they will normally do this for free.
You need to have between 13.6 and 14.4 volts.

 

I very recently had the exact same symptoms....

Summary:
I thought my alternator was fine until I removed it and had it tested. I replaced it with a fully functional alternator and all my problems went away.

Background:
I removed my battery (because thats easy to do), tested it, had someone else test it, and confirmed it was good.

I initially thought my alternator was good because I tested it with my multimeter (voltage drop test) while it was still in my D2. Very soon afterward I realized I'd gotten bogus results because of a flaky multimeter.

I drove my D2 to an autoparts place and they tested my alternator with a hand held unit while it was still in the vehicle. They said it was fine.

Since my problems persisted, I eventually removed*,** my alternator and took it somewhere (another autoparts store aka "O'Reilly") to have it "bench tested"/ tested in an alternator testing machine. They spun up my alternator and it was only putting out 11.52 volts. Bad alternator.

I replaced my alternator and all has been well since.

*Always disconnect the negative connection from the battery's negative terminal before you start removing your alternator.

**BTW... for those of you who may not yet know it.... removing/installing your alternator is a quick piece of cake if you have a serpentine belt tool kit. This tool costs $19.99 at Harbor Freight or you can rent one for free at many autoparts stores (O'Reilly and Autozone). With this tool you'll be able to easily remove and refit your serpentine belt BY YOURSELF in less than a minute.
Here's a list of techniques I found worked best for me when I removed and installed my alternator multiple times... Maybe they'll work for you too:

when removing...

when refitting...

I hope this helps someone. It'll be nice to contribute for once.

Cheers,

Thomas

 

what are you talking about all you need is a wrench, and half a second to take your serp belt off the alt pully.

 

Like I said, it's all technique and everyone should use whatever works for them. It's the result that matters and not the tool or technique etc etc.

Having said that, and since "tweakover" asked me what I was talking about, I'll explain:
There's probably a couple of different reasons why "tweakover" only needs a wrench and/or why just using a wrench works better for "tweakover" than it does for me:
- maybe "tweakover" is stronger than me and/or his hands are bigger than mine
- or maybe his wrench is a lot longer and thinner than the one I have
- or maybe his tensioner is getting worn out and/or doesn't put as much tension on his belt as my new (only 1800 miles) belt tensioner puts on my belt...

Whatever the reason, my technique is to use whatever is available to me that will help me to do whatever I need to as easily, quickly, and with the least amount of frustration and/or skinned knuckles as possible. In my situation, if my eight - ten inch long 15mm wrench was that tool, or all I had available to me, I'd happily use it. But in my case, unlike "tweakover's", my 8 to 10 inch long 15mm wrench was not that tool. (I wish it had been because it would have saved me a trip to the autoparts store.) So I found a cheap (since I "rented" it from O'Rielly it was free) purpose built tool that made removing my serpentine belt, for me, almost effortless, nice and easy, with no fuss, no muss, and with no skinned knuckles.

Cheers,

Thomas