2001 DISCO II
140,000 miles (2nd owner, 1st owner drove it to 50k)
Original Bosch alternator (or at least original to me)

While driving to work today I noticed that my battery light started flickering on and off. After about 5 minutes, the light just stayed on. I continued on to work, another 5 miles, and parked it. This afternoon I went back to it and it started right up, but the battery light was still on. I drove home -- about 12 miles -- with everything I could think of off hoping I wouldn't get stranded. Thankfully I made it.

I checked the battery and it is only about a year old. There is no corrosion, connections are right, and the wires leading to the alternator seem to be good. The belt for the alternator is not loose. I took some readings with a multimeter. With everything off, the battery reads 12.58. When I turned on the ignition, the reading dropped to 12.18. When I put on the radio, A/C, and lights, the reading dropped to 11.75.

Should I replace the alternator or is the further testing I need to do? Thanks! Appreciate the help!

 

Test the voltage with the engine running. Shouldn’t be lower than 13.0v normally 13.2-14.1v when the alternator is charging.

 

Sounds like the alternator is about to go titz up.
But to be sure run down to an Advance Auto Parts or AutoZone and have them do a free Load Test.
Simple enough, and it's done right in the parking lot.

 

Thanks Best4x4 and sorry I wasn't more clear. With the engine running, I got 12.18 (versus 12.58 when off). My understanding is that 12.58 is basically perfect, but obviously, the 12.18 is low. Does that mean my alternator is still charging, but not sufficiently, or that it isn't charging at all and it is totally my battery? Do I need to troubleshoot/test anything else before replacing the alternator?

OverRover -- The nearest AdvanceAuto/AutoZone are about 15 miles away (30 miles roundtrip). Do you think I have enough juice to make it? Thanks!

 

With engine on it shouldn’t normally drop below 13.0v sounds like it’s dead. You can get a slightly high amp unit of 150amp vs 130amp if you buy one for an 00-02 Range Rover.

I’ve had very good results with aftermarket alternators made by Parts Player.

 

Thanks again Best4x4. I'll look at the 150 amp version you recommended. How hard a job is to replace the alternator? It looks like it is three bolts, but do I need to remove the belt? I've never taken the belt off before and I'm worried I won't be able to get it back on. Other than that, it doesn't look too bad -- understanding that looks can be deceiving.

 

Disconnect the battery with a 13mm, then a 15mm on the tensioner pulley will let you remove the belt, the alternator is held into place with 2 13mm bolts, then you have 1 10mm on the back along with a 13mm nut for the wiring connectors.

Once all the wiring connectors & bolts are removed take a flat blade screwdriver or a small breaker bar and place it between the alternator & mounting bracket to get it to rock free of it’s mount. Then when installing the new one tap in the little caps that move when you tighten it (they’re on the alternator where the bolts slide thru). That will make the alternator just drop into place. Start to finish shouldn’t take more than 20min with just common tools.

 

Awesome! Thanks Best4x4! Ordering now and I'll let you know how it goes. Is there any issue with using the Bosch AL0807N? It is also 150 amp and I can get one quickly.

 

Should be good to go anything that works has to be better than nothing lol.

 

Thanks. Amazon had one in the Amazon Warehouse for $65 that they claim is "like new". Hopefully just someone who decided to go with something else or a crushed box. I've always had good luck with Amazon Warehouse so I'll test my luck. Thanks again for all of your help.