1994 XJ Alternator Issue

[cm12385]

1994 XJ
4.0 six - AX-15 Manual - Four Door - Largely Stock

I bought this XJ from a friend and when he owned it we swapped the alternator with a Autozone Duralast unit around 2006 - 2007 timeframe.

Within the past we months, when I run the XJ through a car wash or wash the motor directly, almost immediately after the alternator shuts off.

I suspect this because the voltage on the gage will drop significantly, the accessories/lights will dim as you would expect. The belt does not squeal when this happens so I am confident that it is not due to belt slippage. However, as soon as the alternator comes back online, the belt chirps. I also assume it is chirping because of the sudden application of load on it when the power returns. It will do this a couple of times after washing then does away.

I removed the connections as the rear of the alternator and cleaned and reinstalled yesterday, washed the motor today, same problem.

So the fix may be as simple as swapping the alternator but I wanted too see if anyone has had a similar problem and if I should look elsewhere before replacing the alternator - hate to spend the time/money and have the problem reoccur.

On a side note, Autozone alternators are now made in China - so I plan to avoid that. What do you all recommend for a reasonably priced replacement? I do not plan to spend $400 plus for a Powermaster or Mean Green.

Also, can I use a 120amp alternator from a similar year 4.0L ZJ?

Thanks,

cm

 

[cm12385]

No input on this issue?

cm

 

[home_brewed96]

Alternators dont just shut off. They will keep on spinning with the engine running. So, I cant offer you much insight there. Check the tension on the belt. You should only be able to "wiggle" it about half an inch at the longest span between pullys. If it moves any more than that, tighten that tensioner bolt (located just to the bottom left of the p.s. pump if its a 4.0).

 

[N8N_99xj]

Not sure if it is the same with 94 to 99, but on my 99 when I had the serp belt replaced, I had the same problem. Serp belts need to be a lot tighter than V-belts to work right, I guess the mechanic just tightened it by feel and it was way too loose. I bought a Krikit and set the tension myself, even at the low end of the spec it felt way too tight to my old fingers used to V-belts, but I haven't had a problem since.

When wet, it would slip badly enough that it wouldn't make noise, then when it started to dry out you'd hear it chirping, which kind of sounds like what you're describing. I first noticed the problem in a heavy rainstorm when I needed to have lights, wipers, and defrost on all simultaneously; as soon as I turned all those acc's on the alt stopped charging with no noise, I initially assumed a bad alt but after looking into it more it was simply belt tension. (now my original alternator did end up going bad a year and a half later, but that's probably because the radiator was dumping coolant into it.)

 

[sidriptide]

When wet, it would slip badly enough that it wouldn't make noise, then when it started to dry out you'd hear it chirping, which kind of sounds like what you're describing.

x2 on this. your belt is slipping when wet and the noise starts when it is drying out trying to grab friction and get up to speed.

 

[cm12385]

Thanks for the replies. I would never thought the belt would stay quiet when slipping, even when wet. I will play with the tension before I consider replacing the alternator.

cm