So who makes the highest quality, durable and reliable regulators these days?

At this point I wouldn't mind buying a separate regulator and upgrading that.

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Might PM Bob ( Motorcarman ) as I think it was he that just replaced his 2 weeks ago with one of the newly available cheaper alternators . The regulator is only as good as the brushes and may not have been looked at as the unit went through the shop . Mine are at 1/2 life as I took mine apart . New regulator not in the mail yet to spin it up .

The Autozone showed a new Denso for 180 . Your home computer uses a different system that doesn't show it from home .

 

Received a new Transpo IN221 ( ? ) - 336 voltage regulator and will assemble it together to spin up Tuesday while I work on someone elses X300 . Don't know if it's the right one

 

Guys, I think you are chasing a ghost. What was it that brought you to Autozone for an alternator, Al? I think you should make one more trip there, and get a refund. There must be better options. Napa or maybe O'Reilly's?

Sure, they claim it is a new alternator, although it is probably a refurbished casing with new parts inside. Fair enough. The problem is, it is made in China or another far eastern country. It will no doubt have substandard parts in it, especially the electronic parts. "Far Eastern" aftermarket rebuilt auto parts are notoriously poor quality. Autozone puts it in a pretty box, says it meets OEM specs (who really knows), and probably offers a lifetime warranty for it. They make it to last a year or two. They deal in volume, quantity, not quality. But almost immediate and duplicated failure is just pathetic. Your original lasted 20 years and 100k miles or so.

We know not to skimp on a battery for these cars. Aftermarket coils are completely out of the question. And a generic Chinese imitation alternator simply will not work either!

 

I hear ya, and typically agree..... however the OEM alternator from Jaguar is $1499, with a $249 core charge. Installed the total quote was $1500.

If the new OEM alternator were $500, I might consider it even though that's expensive, but I can't justify $1300-1500 for an alternator. That's nuts.

Even a remanufactured alternator from Jaguar is $500.

...hence my giving the aftermarket $200 alternator a try.

Now, what's interesting is that all three (OEM, 1st Autozone, 2nd Autozone) have failed the same way with intermittent charging. So that's why I'm starting to wonder if it may be something other than the alternator such as perhaps the regulator power supply.

I really only have time on the weekends to work on the car, and need nice weather to do so, so hopefully I can do some testing this weekend to see if that power supply may be an issue.

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Denso alternators are also used by other brands of cars, maybe a less expensive alternative exists? I agree, $1500.00 for an alternator from Jaguar is nuts. I think I remember seeing that even Chrysler used Denso.

 

Chrysler mini vans are one source I can think of off the top of my head , it has to be a 120 amp model . But then that's dependent on internet information vs. actual hands on seeing . Have to source some screws I had to drill out of the old voltage regulator before I can spin up my alternator at Auto Zone to find if the new regulator is good from that repair approach .

 

Will be interesting to see if Autozone can test it. Their test machine wasn't able to test their own alternator according to the machine's computer when I brought the first one back.

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Saw their machine as I was looking for some screws , the machine does not have a load bank to test the suspected ( in my opinion ) mode of failure in higher current ( excitation voltage related ) through the regulator heating it up to a fail point as you increase the demanded load .

 

Wow. I have never been impressed with Autozone as a true auto parts specialist, and I still am not. It is the place you go to buy overpriced fluids, substandard batteries, and cheap generic trinkets. From China. Ok, I'll stop now!

I'm also not suggesting you spend big for the new original, either. I'm saying that the other stores can get you what Autozone can't - a remanufactured unit that will work for a while. Maybe the ones rebuilt in Malaysia or Singapore are better than rebuilts from China!

I doubt that it is the car's fault that the alternators failed. But due diligence is still appropriate.

 

Anyone have the route of the alternator battery charge wire and any intermediate connections between it and the battery?

....I'm checking connections, such as the engine to body ground strap.


Another question, to clarify, can a bad regulator cause intermittent undercharging, or only overcharging?

Intermittent undercharging(low voltage) at low RPM is what I'm experiencing. Before I order a new regulator, I just wanted to verify that undercharging can also be a symptom of a bad regulator.

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Quote "Intermittent undercharging(low voltage) at low RPM is what I'm experiencing." Where are you measuring the voltage? Are you just observing on dashboard voltmeter? I would want to check output directly from alternator as a first step.

From memory, the main power cables go from battery in boot to 100a (?) fuse under rear seat, then along the RH floor inside car to bulkhead on RH side. Cable connects here to bulkhead on LH side behind the dash.

Both of those go through the bulkhead (these connections are prone to corrosion) to engine fuse boxes and (I think) to starter and alternator on LH side.

 

G'day Gents,

I've just gone through the process of replacing the alternator in my V12 X305, the old one was charging at around 12V and as the car has over 300,000 kms on it I thought I'd just replace it.

All done and checked the charging voltage, just on 13V measured at the battery but 14.4V measured at the terminal on the firewall under the bonnet/hood.

So I need to go over the cable from the battery to and including the firewall and clean all the connections and the battery earth point. I'll let you know how it goes.

Cheers,
Jeff.

 

The bulkhead terminal question is the center one as it comes up from the starter as the starter is a tie point for the single heavy B + wire alternator output wire .

Someone's some bulkhead terminal was loose and I advised him to tighten 2 nuts together on the end of the terminal bolt so you can hold them to tighten the 3rd nut next to the bulkhead that responsible for clamping the wire terminal on the cabin side . Very hard to reach from the cabin side .

Someone mentioned they found the 2 fuses terminal bolts loose in the black box that hangs down from the battery B + post .

Al I'll get you the link to the new regulator I bought , Have not spun tested it yet as it is missing some regulator terminal screws .

https://www.ebay.com/itm/NEW-QUALITY...xYAYV7&vxp=mtr

What they sent me was a IN221-3636 as stamped on the part

Editing

 

G’day Gents,

As a follow on from my previous post, today I went over all the connections on the power cable from the battery to the firewall terminal post and made some interesting discoveries.

Firstly in the heavy duty fuse box attached to the battery +ve terminal there are two 250amp fuses, both were barely finger tight. I took them out and wire brushed all contacts and reassembled it.

Secondly I checked the junction under the rear sear RHS. There is a heavy duty junction/ fuse box there under a foam cover. Again the nuts were barely finger tight. Took it all apart and cleaned the contact points and reassembled it all.

Thirdly the firewall terminal post where the heavy duty cable runs from/to the alternator/starter motor. It was a bugger to get undone as the whole thing rotated when I tried to undo the outermost nut but I persevered and succeeded in getting it disconnected and out. The under bonnet/hood cable was tight but the cable in the footwell was loose and there was evidence of high load and some scorching on the insulator.

I cleaned everything up as before and reassembled the whole thing.

Now for the moment of truth, I reconnected the battery, on which I had also cleaned the terminal posts, and started the car.

The dashboard voltmeter was indicating a little over 14 volts which double checked with a digital meter. Success!

For the first time since I’ve had the car full charging volts are indicated. I should’ve checked and cleaned the power cable ages ago. There was a loss of around 2 volts from the firewall terminal to the battery all due to dodgy or dirty connections in the heavy duty power cable and more than likely nothing wrong with the original alternator!

I’m having a cold beer to celebrate!

Cheers,
Jeff.

 

Very, very well done! A lesson for us all!

 

watto700, thanks for the great info! I am also having occasional low charging problems with my alternator. At night with the lights and heater fan running the lights dim and I see the gauge dipping. This is always at a stop and low rpm. If I put the shifter in neutral it brings the rpm up as well as the charging rate.

I had cleaned the big terminal and cable on the back of the alternator but that did not help. I also found the terminals on the fuse box + terminal to be loose.

I need to check the connection under the back seat, is it visible when you remove the right side kick cover?

A question about the firewall terminal, did you actually remove the whole stud? Does this mean you have to get under the dash to remove-replace it?

 

Just as important is the ground wire on the above print below the alternator . On the center bulkhead terminal to just ensure that it is tight will get you better as crawling way up under the dash is not easy but ensures you don't have any as one would suspect arcing or corrosion damage . Same can be said of the battery negative post to ground but is much easier to get to .

Scotland , my apology for not giving you credit for your finding on the 250 amp fuses some time back but I'm lazy in going back and retrieving old post and who they came from .

 

G’day Scotlad,

In answer to your questions,

I need to check the connection under the back seat, is it visible when you remove the right side kick cover?

To gain access to this connection you need to remove the rear seat cushion. Firstly remove both kick covers and then you will see two Phillips head screws which secure the seat cushion, remove these and the seat should pull out fairly easily. You’ll be amazed at what you find under the rear seat, I found a bottle opener from a brewery in Scandinavia!

Once the seat is out the connection is under the insulation on the RHS, remove the retaining clips and peel back the insulation and you should see a triangular rubber pad, the connection is under this. Simple eh? Ha!

A question about the firewall terminal, did you actually remove the whole stud? Does this mean you have to get under the dash to remove-replace it?

I removed the whole terminal and cleaned up all the components. I found access to is easier when I removed the RHS panel below the instrument panel and the aircon duct behind it. I put the front seat all the way back and lay flat on my back in the footwell to gain access to the terminal. You’ll either need an assistant to hold one end while you work on the other or some vicegrips to secure it.

Cheers,
Jeff

 

Thanks for the update, and agree on checking all the connections. I did some searching today in the X308 forum on this topic, and no surprise, this is a common issue on the X308 too....

Here are some related threads in the X308 section:

https://www.jaguarforums.com/forum/x...rnator-108656/

https://www.jaguarforums.com/forum/x...ernator-92313/

https://www.jaguarforums.com/forum/x...-output-86136/


....wish I had seen this info before. If this turns out to help with my situation, I probably had a good alternator that has now been sent off to "Autozone core heaven".

Too bad, but always learning something new.

Two other new things learned from reading all those threads:

1) Clean and remove any paint from the contact points where the cables are mounted to the body as just a star washer or thread contact is not ideal.

2) Apply a conductive (not dielectric!) grease such as NO-OX-ID


Hoping to have time this weekend to get to it, and since I'll have the back seat out, maybe I'll finally get the subwoofer repaired too.

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