Alternator - to replace or not?

[Jpdv]

OK Folks, comments please:

I am at 200k on the original alternator. It's still fine, but I have an OEM Denso replacement in the shed. Do I go full preventative and swap in the new one, given the mileage, or do I wait until 'something happens'? (I'll keep the old one as an emergency spare if I do this, but by this logic could leave it there with a brand new shiny one as my emergency spare...)

What would you do and why?

Thanks!

[DieselLSE]

I'd change it over. I'm at 130,000km (December 2013 build) and already thinking about a new one, perhaps sometime around 170,000km or if I ever need to do any major work on the engine (inlet manifolds, turbos etc).

[Eric SDV6SE]

Replaced mine at 160k km preventatively, i was getting some transient errors. Pulley bearing was also getting noisy.

Alternator is at bottom right of engine (when viewed from drivers side) so not related to manifolds or top of engine access. relatively easy changeover, a few extension pieces. Hardest part is the cable at the rear,for some reason JLR decided to make this cable ridiculously short, so you're fitting the locknut and washer on blind.

[Jpdv]

Thanks guys - I think it makes sense to bite the bullet. Yup, I've seen some comments around that cable - I have large hands, so it'll be a bit of a curse-fest, but its only time, and overall the job doesn't look too challenging...

[josh.huber]

Thanks guys - I think it makes sense to bite the bullet. Yup, I've seen some comments around that cable - I have large hands, so it'll be a bit of a curse-fest, but its only time, and overall the job doesn't look too challenging...

You'll be right, I did one in 2hrs once so I could make it to pick my daughter up from school.. Had to come home and recheck everything. But if you allowed 3 you should be fine. I'd keep the old one as the spare.

[Narangga]

Replaced mine at 160k km preventatively, i was getting some transient errors. Pulley bearing was also getting noisy.

Alternator is at bottom right of engine (when viewed from drivers side) so not related to manifolds or top of engine access. relatively easy changeover, a few extension pieces. Hardest part is the cable at the rear,for some reason JLR decided to make this cable ridiculously short, so you're fitting the locknut and washer on blind.

Ain't that the truth. Denso unit which was new in 05/16, 105K km. [bigsad]
Being replaced on Thursday this coming week as we are off on a 2 week jolly three days later.

[veebs]

Replace I reckon. They die, and when they do, they can take out a battery, potentially catching fire.

I’m on my third at 215k…

[shanegtr]

Never replaced mine and as far as Im aware its the original, at 408k[bighmmm]

[Jpdv]

Damn you Shane! Now I'm tempted to wait and see! It'll go on me somewhere horrible if I do, of course...[bigwhistle]

So another question - do they tend to fail gracefully/slowly, or is it a sudden terminal grinding to a halt in the middle of nowhere? That would influence the chain of logic, I guess...

[DiscoJeffster]

Just. Change. It.

[Jpdv]

Just. Change. It.


No, no, indulge my indecision! [bigrolf].

It'll be getting changed. I have the serpentine belt replacement sat ready to go as well, so I reckon it's that time. Seriously, thanks to all for the comments.

[Xtreme]

I had an alternator die on me last weekend when I was 530km from home - Td5 Defender with 226000kms.

I managed to drive home by using two batteries and one overnight stop to recharge the batteries.

With the Nanocom running on instrument mode I was able to watch the battery voltage drop to about 8.5v before handbrake, traction control & abs lights came on. Then at 8v speedo stopped working and soon after the fuel gauge also stopped. At 7.5 volts, engine light came on, engine misfired once so I pulled over and fitted the spare battery and off I went again. This all happened after only 100kms and 1hr.

After recharging both batteries overnight and borrowing another old battery from a friend, I started off the next morning expecting to get about 100kms from each battery. However this time I didn't switch the Nanocom on and was surprised when I got 320kms out of the first battery and arrived home on the second battery after another 110kms and battery still reading 11.8v.

Moral of the story - if you need to run with a non functioning alternator, switch off all accessories including your Nanocom, which appears to suck quite a lot of power from your battery.

New alternator now fitted and original battery still appears OK.

[Discodicky]

OK Folks, comments please:

I am at 200k on the original alternator. It's still fine, but I have an OEM Denso replacement in the shed. Do I go full preventative and swap in the new one, given the mileage, or do I wait until 'something happens'? (I'll keep the old one as an emergency spare if I do this, but by this logic could leave it there with a brand new shiny one as my emergency spare...)

What would you do and why?

Thanks!

I started a similar thread here a coupla weeks ago.
At 172,000 klms the voltage went to 15.1, normally 13.8 to 14.1, so I replaced the battery on the basis that it was 4.5 yrs old and maybe the alternator was working overtime with a weak battery.

A long story short, even though I've had two persons re-set the BMS, the voltage has been 15.1, then down to 12.1 then back to 15.0
So I ordered a new Denso from TR Spares last week and will fit it when it arrives.
Presumably that'll fix it!

I consider it was due for a change anyway, before I go Mainland travelling early next year.

Next are the inlet manifolds and oil filter assy........

[rambada]

Our alternator just died at 240K - getting replaced this week. No signs prior, just the warning light came on, OBII confirmed it.

[Tombie]

They fail rapidly.

Mine was fine one drive, parked up and next start it failed.

160,028 km when it died (mine is under quite heavy load)

[Plane Fixer]

Replaced mine at about 220000 simply because I did not want a failure.
Recently had water pump, oil pump, manifolds, oil cooler and starter motor replaced before anything broke. Simply preventative maintenance due my aircraft maintenance background. They are an expensive car to keep, but at 300,000k it is still the most comfortable long distance cruiser and enjoyable to drive.

[Ghost-Who-Walks]

Another vote for replacing it.
I bought a spare and then replaced it (before failure of the old one) around 220k kms. I just didn’t want the hassle (& possible cost) of failure whilst driving.

I’ve kept the old one as spare, but given it will definitely fail sometime (& much more likely after 200k kms), worth getting done. Unless you like getting stuck on the side of the road!

I got my indie to do it when they were servicing my vehicle, so minimal additional cost…

😄

[Narangga]

Replaced today after 5.5 years and 105,000km, although admittedly it was the pulley bearing making the noise that precipitated the replacement.

[Ian Abbott]

Yep, change it out under controlled circumstances rather than say, the day you wanted to put the wagon on a booked ferry trip or other planned event[smilebigeye]

[pedro54]

Replaced at 190,000km, diode shorted inside the alternator. Cannot predict that type of failure. No bearing noise.




Peter

[Tombie]

Replaced at 190,000km, diode shorted inside the alternator. Cannot predict that type of failure. No bearing noise.




Peter

That’s the common failure.

And you can predict it [emoji41] if your alternator is 150k-160k old, it’s about to fail soon [emoji846]

[Jueylea]

My votes on replace, I'd been 'meaning' to get a spare. Just had inlet manifolds done preventatively and at 160K and about to become totally dependent on the D4 alternator failed. 4 days later and there would have been much more grief.