Okay, this will be a somewhat long post as I will try to detail out as much information as I can and give my synopsis as well so that I may get some feed back.

For the past few months my Disco 1's RPM gauge has not functioned properly. Only after driving for a few miles will the gauge begin to work. This only started happening after I took it to a local mechanic for him to diagnose a earlier problem with my lifters. During this whole fiasco, he also replaced my water pump.

Finally a month or so ago, my battery completely dies on my while going down the road. My RPM gauge at this point had completely stopped working. I remember reading something on here that the alternator acts as your RPM gauge, so I though, hmm, if the alternator is spinning properly and the RPM gauge isn't working, then surely my alternator must be going bad. So I took the alternator to a shop and sure enough, bad diode. Cool, problem fixed, so I thought.

After I replaced the alternator the RPM gauge still did not function. Sitting on pretty much 0 the whole drive. Well the battery died again. So, I had it charged at a local parts store and the guy who charged came out to see what the issue was. Well my tensioner pulley was incredibly loose, even I could see that as the belt wabbled in it's path. So, I forked over the money for a new pulley, hoping that this would fix my problem thinking that not enough tension on the belt would cause the alternator not to properly charge the battery and thus my RPM gauge would also not be working. Well, this time, the RPM gauge worked for a short time after installing the pulley, then nothing. Back to a dead battery.

A few weeks ago I was listening to the engine and I could hear a slight grinding sound that seems to be coming from the A/C compressor. Of course thoughts arose in my mind about how if the A/C compressor's pulley isn't turning fast enough due to a bad bearing, then the alternator wouldn't be turning fast enough...blah blah blah.

But before i do anything I wanted an opinion. I have spent far too much time and effort into this for the next thing I throw at it not to work (especially since an A/C unit isn't cheap).

So, here are my thoughts:

One: it's the AC Unit. Replace that, belt moves at optimal speed, battery charges, problem solved.

Two: Get a AC Unit Bypass Pulley

Three: Get a shorter Belt and Bypass the AC Unit the old fashion way until I can afford another AC unit.

Four: The guys who originally installed my water pump put the wrong size belt on my Rover.

Five: It's something completely outside of everything I've already said.

Please give me some help, ideas, methods, anything. I really would like to get this thing running again in the next week or two.

Thanks,

 

So I don't have to read your overly long thread, put into 2 sentences what is going on and a question.

 

Mike, I can't say that I don't find all of the information incredibly important, which is why I included it. But here you go:

Basically, my battery wont charge no matter what I do. I have replaced the alternator and tensioner pulley; the water pump has also been replaced (not by me) and a new belt was put on in the process. My RPM gauge doesn't show any tact at all and my A/C unit bearing sounds like it's going out. I don't know which of these many possibilities is the culprit.

Thanks,

 

The A/C bearing will not affect the alternator, the A/C will spin at the same speed as everything else until the bearing seizes and then shreds the belt.
You can replace yoru A/C bearing.

http://www.roverparts.com/TechTips/s...g_defender.cfm

Check your belt routing, it is very common for the belt to be routed wrong and then not charge the battery because the alt is turning to slow.
Yes your tachometer runs off the alt, check all of your electrical grounds, if they become correded they can cause problems.

http://www.roverparts.com/TechTips/g...l_problems.cfm

 

Man, I HATE when my tach lacks tact!

 

Thanks for the easier to read version.
How do you know tour alternator is not charging, is you warning light on, have you gone and had the battery/alternator tested at the local auto parts store. The voltage with the engine off should be around 13.6 up to 14.4 or so with the engine running.
Have you check to see if you have a major short/draw, that is discharging the battery over night.
The tach not working is a good sign it is the alternator.
Let us know what you find.

 

Hey guys, yeah, I've had the battery and alternator tested, which is why i replaced my alternator. But I have to say I finally fixed the problem. Spike you were right on man. The belt was totally routed incorrectly. I pulled up a routing diagram from online and checked mine out. The guy that did my water pump routed the belt straight over the top of the alternator to the power steering pump, instead of down around the fan.

I pulled the belt into place (which was incredibly difficult to do), and wa la. Fixed. Battery is charging, Tach (tact :-)) is working. Everything is good. Now I just need to figure out what my car started to overhead after I moved the belt into the correct position. Any ideas about that? Have plenty of coolant and I don't see any horrible leaks. Only happened after I routed the belt correctly.

 

SWEET!! I got one right!!
So now it overheats...coolant is full...
Look at that diagram again and see if you are spinning the water pump backwards now.
I dont know if that is possible but if the belt is again on wrong...

http://www.roverparts.com/TechTips/s...g_defender.cfm

 

Similar situation here. My battery wont charge no matter what I do. I have replaced the alternator twice and the battery is brand new and good (holds a charge fine). The alternators test fine when taken out. The tach has worked only intermittently for a couple of years. Voltage at both the alternator and battery are the same when running, i.e. lower than the ~12 volts at the battery when the Disco is switched off. The situation has gotten progressively worse over the last few years and now if driven more than a few miles the battery drains and the Rover dies. The belt and tensioners are fine. Please help!

PS, I have a '97 V8 5MT Discovery - purchased it when brand new.

 

You could try checking the grounds. Check the negative battery cable and any ground straps, or wires from the engine to the frame and body.