Thread: Alternator overheating

Whilst an alternator should be simple fix for any auto leccy, the Land Rover does come with its own foibles!
Is you mechanic a Land Rover specialist?
Assuming they ordered the new one, it should be covered by a warranty, but if the problem was not diagnosed correctly in the first place, and the original problem is not fixed, then putting a new alternator onto a faulty system is not a good move.
Has anyone read any fault codes? If they have, do you know what they are?
The codes can help avoid the "shotgun approach" to parts replacement.
I have an 06 D3 and replaced the alternator about 4 months ago at about 130K. I was getting a charge warning light coming up intermettently. When they checked the codes, they matched up with the problem.

I suggest that the mechanic have the new alternator checked by an auto-electrician.

For reasons unknown the pulley wheel on my 110 alternator became loose and began making noise and the wheel was getting very hot.

Touch the wheel. It will be a bearing or the wheel is not torqued up enough.

I fixed my alternator wheel with a rattle gun. All good now. Not hot or noisey.

How many amps is it putting into the battery at the moment, they are a 170 amp alternator on the late d4's. I'm guessing this is similar .
If you drove it on with a low battery because the old alternator wasn't charging the battery will be low, on top of that they probably checked it at idle, alternator working it's hardest to maintain voltage and internal fan not spinning fast.
Tell them to put the battery on charge over night so it's full. Install alternator, test by running at 1300 rpm, test voltage and amperage. They do get hot, I'll often put my hand on one to see if they are charging if I dont have my multimeter handy.
All the best

Thanks for the input, much appreciated.
I live in a country area so they are not a Landrover specialist nor dedicated auto electrician.
I have read a couple of threads about the diagnostic tools but unfortunately I do not have one and I am not sure what they have used.
One would assume they have ruled out all of the basic things.
The car had a new battery put in it and was only driven 25 mins each way home and back to the mechanic shop since that time and there it remains.
I do understand that if the battery is flat the alternator would have a higher charging rate but surely this is limited so the alternator does not get so hot and on top of that they would be aware of it and check the battery first.
I have not heard the car run with the new alternator in it. Due to the new alternator overheating, when I stopped in on Friday afternoon they had removed it again and it was sitting on the bench and the old one had been put back, presumably for troubleshooting purpose??? I didnt ask them whether the charging rate out of the new alternator was correct or not but you would imagine they have checked the new alternator thoroughly and if there was any doubt they would have ordered another.
I will say the car was idling ridiculously high the last time I drove it. I doubt its the pulley overheating when its a new alternator. Sounds like need the correct diagnostic tool to get all the codes.

Originally Posted by jimd377

Hi all.
Recently purchased an 05 D3 V8 disco and have been experiencing a few electrical issues unfortunately.
After finding the car dead one day very soon after purchase had the battery tested and was told it needed replacing, at that time the alternator was tested and was supposedly charging. No battery lights were illuminating on dash. Did have some warning faults which can apparently happen with a flat battery.
Had a new battery installed only to be told it now does need a new alternator. Ok so thought it has 143k on the clock and at least shouldnt have to worry about it going on future trips if its changed out now. Had to wait a couple of days for the new alternator to arrive. The battery light did come on and off a few times while driving home and then back to the mechanics. There was a relatively loud wherrrring noise coming from under the bonnet that had not been heard before.
New alternator arrives at mechanic shop, they install it and apparently it is overheating. Was told it cant be left like that or the new alternator will be damaged also. They said it was that hot you couldn't touch it. At that point late this afternoon the old one had been refitted and the new one was on the bench again and they were at a loss indicating it was a landrover computer issue but that they werent really sure. One would presume they have ruled out the new alternator being faulty somehow. They were going to make some phone calls to try and sort it.
So the disco is still there.
I know the details are sketchy but thats all I have.
Does anyone have any ideas on what is going on?. Feeling frustrated and stuck between a rock and a hard place.

check they’ve got the right part number this is from Rimmer Bros website; Genuine Land Rover Alternator - YLE500390 | Rimmer Bros


Also check that they’d got the right pulley size running on it.

Originally Posted by jimd377

Thanks for the input, much appreciated.
I live in a country area so they are not a Landrover specialist nor dedicated auto electrician.
I have read a couple of threads about the diagnostic tools but unfortunately I do not have one and I am not sure what they have used.
One would assume they have ruled out all of the basic things.
The car had a new battery put in it and was only driven 25 mins each way home and back to the mechanic shop since that time and there it remains.
I do understand that if the battery is flat the alternator would have a higher charging rate but surely this is limited so the alternator does not get so hot and on top of that they would be aware of it and check the battery first.
I have not heard the car run with the new alternator in it. Due to the new alternator overheating, when I stopped in on Friday afternoon they had removed it again and it was sitting on the bench and the old one had been put back, presumably for troubleshooting purpose??? I didnt ask them whether the charging rate out of the new alternator was correct or not but you would imagine they have checked the new alternator thoroughly and if there was any doubt they would have ordered another.
I will say the car was idling ridiculously high the last time I drove it. I doubt its the pulley overheating when its a new alternator. Sounds like need the correct diagnostic tool to get all the codes.

Hey mate,

Driving an hour without an alternator is a long time in one of these, they have allot of electrical load, I drove my d4 for 30 mins when my alternator died and it got to 12v, mine didn't do the diode failure that kills them very quickly, just died quitely.

Alternators normally regulate voltage, these cars use the body controller to monitor the amperage and voltage, I doubt they care about the heat of the alternator when they control these things, the body controller will see that the battery is low and attempt to boost charge it, this is covered by many Tim from traxide as he has designed his isolators to work with this system and informed us how it works.

Again they need to put the battery on charge, I never like throwing an alternator at dead batteries, if they are a basic mechanic there is probably nothing they can do to test it.

If it has a failed diode the could hook a battery up to it and see if it has any current draw. Connect a jumper cable to the earth terminal of the battery, and to the body of the alternator, hook up the positive to the positive terminal, tap it on the b+ of the alternator, if it sparks, the alternator likely has a failed diode. If no sparks use a multimeter set on amps between the b+ and the positive jump lead, you really shouldn't see anything above an amp.

This is the only thing besides over charging that will make a alternator hot, besides mechanical failures, bearings pulleys etc, all can be checked easily.

Josh

I imagine its not genuine as presumably that would cost a lot more.
In hindsight buying genuine might have been a smart move.

Originally Posted by Eric SDV6SE

check they’ve got the right part number this is from Rimmer Bros website; Genuine Land Rover Alternator - YLE500390 | Rimmer Bros


Also check that they’d got the right pulley size running on it.