Thread: Alternator failure without warning - can it be anything else?

Originally Posted by drivesafe

Hi again bbyer, and this may be the reason LR have fitted the D4 with a 180 amp alternator

Is the D4 3.0 alternator the same as the D4 2.7?

Are the D4 alternators made by the same manufacturer as the D3?

Finding data on the D4 alternator is difficult as all D4's are still on factory warranty, hence there is no aftermarket yet. As to manufacturer, all I know is that Denso did the units for the 3's.

I have a partial LR parts file for the D3/LR3 so I can find some parts numbers and then cross reference some of them.

It appears that the D3/LR3 alternator for the petrol V6, (LR008862), is different than for the petrol V8, (LR008860), but I do not know for certain about the diesel 3's other than for the 2.7TDV6 which is LR008861. As to the D4's that is really a black hole.

It reminds me of when I first got my LR3 - like it was designed off planet - just no data available other than on Disco3 and AULRO.

What I have been looking to find is a 180 or 200 amp version of the Denso part numbers 4280003690 or 4280003691 which are I think cross for the Land Rover YLE500190 or newer part number YLE500390 or LR008860 which is what LR calls a service exchange unit - rebuilt I suppose.

I cannot imagine that our alternator is so unique that something similar is not sitting on some Lexus, BMW, or Jag.

I can see that the mounting setup may be different, but inside, the parts must be similar to some other alternator. Also 150 amps, while not small, is far from being what would be considered a large alternator.

If there is anything that may be unique about our alternator, it is how it interfaces with the Engine Control Module and that Pulse Width Modulated signal that controls the amp output of the alternator. As such, some sort of straight across swap because a unit physically fits may not be the best idea.

DENSO Automotive OEM Products

I've been in contact with my LR Specialist mechanic, he will be emailing me diagrams of the 2 D4 alternators.
The 2.7TDV6 has a part # LR008043 which is a 140amp model, why the part number has changed who knows!
The 3.0 SDV6 has a part # LR013847 which he is investigating the amp out for. They appear to have similar mount points but without putting them side by side it is just guessing if it fit.
I'll post the diagrams when I receive them.

I tired a Google search on your D4 part numbers, and they are definitely D4 unique numbers, as nothing comes up on the search.

Not to anyones surprise, there is also no rebuilt cross reference as these alternators are too new.

Well done; now I wonder if the alternator internal voltage regulators talk a different language to the Engine Control Unit than they did on the D3 and hence the different part number?

Hopefully it is just that the alternator puts out a bit more amps. I had the feeling that some of the alternators for the smaller engine D3's were rated at 85 amps. I never did figure out what the petrol V6 was either.

Originally Posted by MelbD3

The car (TDV6 SE) was in the Kimberly. There was a day trip that had 40 creek crossings in 60 km - hence 80 raisings of the car to offroad height in a day.

If you haven't done so already, for the compressor's sake you might like to consider one of the methods available to keep the vehicle at off-road height in these conditions, perhaps avoiding the possibility of not being able to raise it when required.

Ok here are the images & part # for the 2.7TDV6 D3 & D4, as well as the 3.0SDV6 part # only unfortunately.
The mounts are different, while the D4 ones may in fact be interchangable. The D3 & D4 Alternators would have to be compared side by side.
No information on Amp outputs available.

I have not touched an alternator since I pulled one of my D2, how hard is it to access and remove the alternators on D3s and D4s.

The TDV8 RR is an absolute nightmare to work on but the supercharge is comparatively easy to work on.

Assuming one is not outside in a -30C snow storm, replacing the LR3 alternator is doable. I say that as I did an alternator change on my Buick Roadmaster, (GM 350), one winter day in about 15 minutes. Needless to say, the LR3 is no Roadmaster.

One pretty much has to remove the alternator from the bottom but to get to the 3 bolts, the drive belts have to be removed and this has to be done from the top.

As such the hard part in my mind is removing the drive belt - actually two of them as the alternator belt is the inside one and to get at it, one has to remove some of the radiator shielding and then fuss with a "triangle" of three bolts on the fan shaft to remove the fan.

A KD Tools #3900 pulley holder will work to hold the pulley bolts while one reverse rotates the Ford fan off with a 36mm open end fan clutch shaft wrench.

My thinking is that once you have spent a day learning how the first time, probably 3 hours in nice weather and not under any pressure should do the job.

I think the turbo diesels are more difficult due to less space.

I am starting to believe that heat is the problem re the short life of the alternators. Here in Western Canada, alternator failure is relatively rare, however in Eastern Canada, common. Here in the West, there are maybe only 60 days a year where one may wish to use the AC; down east it is double that and for Australia, probably closer to 250 days a year.

Also I presume the turbo diesels run hotter under the bonnet than the non turbo charged petrol vehicles.

It would be interesting to know just what fails. I figure it is either the diodes in the rectifier or the voltage regulator thing that the PWM signals feed into. My guess is that it is the rectifier that fails due to heat exaustion and that a heavier version would solve alot of problems.

Other than that D4 alternator rated at 185 amps, so far, the largest Denso SC2 alternator that I have seen is 160 amps and that is in Jeep and Dodge Minivan products as well as some Chev Cobalts. I think the upgrade parts are out there, the trick is to find them.

I suspect that the voltage regulator is unique to the 3 and hence upgrade versions of it are not available; hence my desire to hope the failure mode is with the diodes as I suspect rectifiers, while unique to a particular alternator design, are not unique to any particular vehicle.

The alternators for the 3 appear to be what Denso calls an SC2 design.