Ok, I'm on my second alternator in 4 months for my 86 XJS V12 Coupe. Again...it's began to fail. I purchased them from a local NAPA store. They do stand behind their warranty. However...I'm tired of these Mexican rebuilt units...they all seem to have bad diodes. I'm going broke on labor to install these. What is the best and highest amp output alternator that will last? I've been through this crap before 20 years ago...a series of bad remanufactured alternators...Any help with sources and part numbers will be appreciated. AC Delco preferred.

 

The later cars had Bosch 115A units and they are durable. However, they have a different pulley and belt, so it's not a drop in replacement.

I've never had much luck with "rebuilt" electrical parts, as the rebuild seems to be a cleaning and a coat of paint. I've actually had better luck with good OEM parts from the junkyard.

I don't suppose there is a local independent electrical shop who does starters and alternators?

 

Thing is, I don't want to throw a salvage part that has much use, and ready to crap out too. No one locally rebuilds these. I'm simply looking for good a aftermarket part, preferably new and not Mexican rebuilt ****.

 

I usually use RockAuto.com for my auto parts, but all they list rebuilds. Sometimes they have knockoff Chinese parts, and I've had good luck with those, especially for AC compressors.

 

Interesting. I have a used alt in my 88' and the only issue I have had with it was the regulator going out.

How much are the remans you are trying? I would call somewhere like Welshent ($165) and ask where their alts are done. Better yet find a local/semi-local alternator repair place to do the job for you.

 

Can your shop put in a GM CS-130? I have installed them into a Series 1 XJ6, Range Rovers, MGB's, old Mercedes, and an Audi. They are cheap, reliable, charge like crazy, and I've never had any issue getting them to fit. They are very easy to wire in and last forever. I usually buy new ones for well under $100 from RockAuto.

 

Take the unit to a local automotive electrical shop and have it tested or refurbished as needed.

I personally have never had much success with the 'rebuilt' or 'remanufactured' alternators from the local parts houses.

 

Throw a new diode pack in it yourself:


LUCAS ALTERNATOR RECTIFIER DIODE PACKS ALTERNATOR REBUILD PARTS : LUCAS A133 TYPE ALTERNATOR RECTIFIER FOR JAGUAR XJ 4955A

 

The later 115amp alternator is a Bosch unit and very reliable.

What kills alternators is HEAT, usually because they are full of oil and dirt. This prevents the diodes and/or regulator dissipating the heat they generate.

My guess is the cheap rebuilt ones use lower spec components which can not cope with the current draw from the XJS. The older Lucas alternator was already stretched to capacity with the later XJS.

A 115amp alternator will solve the problem for good. Just keep it clean and it will pretty much last until the bearings wear out. I have also seen people relocate the rectifier and regulator out of the alternator onto a good heatsink.