Jag hasn't been charging over the past 3 days or so. Checked engine bay and boot fuses, all good. no significant drop in voltage from alternator to firewall, or from firewall to battery in the boot so harness is good. With engine running and all electrical items switched on as load voltage at positive post of the alternator is slightly lower than battery voltage. I marked the pulley and the belt, and the alternator is spinning and doesn't seem to be slipping.

My brother (Audi Mechanic), says is almost definitely a dead alternator, and they can just quit suddenly. Replacement alternator the likely fix?

 

Certainly sounds like it.

 

I'm on my 2nd alternator in 4 weeks. The new one died slowly after install as it had a bad diode. Rebuilt alternators are 50/50 reliable.

 

Yeah couldn't be doing with a refurbished alternator going in 4 weeks, was gonna just stick a new one in for 250.

 

250? You must be talking pounds v dollars. If I could have found a genuine new alternator for 250 dollars...I would have bought it. There doesn't seem to be any new ones around?

 

It would be from BritishParts, which sells jaguar spec or OE equivalents, and yes £248. Think its going to be a sooner rather than later thing, since I put in a good fully charged battery this lunchtime and it almost died on me and id only done 8 miles. Thought the voltage gauge was just being silly but then the lights dimmed, battery light came on, trac light, then restricted engine performance, could barely get the car up the drive.

Definitely getting a new one this weekend.

 

Once that alternator quits, the Jag eats volts like a fat kid in a candy shop. You're lucky to make it home. Been there, done that.

 

Ended up getting a genuine refurbished alternator from an independent jaguar spares place up north, sending my knackered one back. New alternator cured the problem, now charging at 14.7 volts again. Was interesting that the alternator that came off the car was a jaguar one from 2011, so 6 years old. But before I bought the car last month, it had only done 1200 miles or so in the last 6 years, so perhaps lack of regular use led to its failure. I've done 800 miles in the past month so getting it back to a proper daily driver.

 

I don't believe for a second that lack of regular use killed the alternator. It's like saying your toaster stopped working because it wasn't plugged in for years. These cars eat alternators period. Most American, German and Japanese cars have alternators that seldom wear out. I've personally gone through 3 rebuilt ones in 6 weeks. My previousl XJS 15 years ago ate 3 or 4 also. It's apparent that theirs a design flaw in the charging system of these cars. Also, don't be fooled by a "Jaguar" original part. It's rebuilt like all of them. Cross your fingers, eyes, legs, toes and pray.