Ok so Iv been getting the check guage light and the voltage on the guage drops to 9v and this happens randomly. So I cleaned all the grounds today, and checked my battery, its at 12.5v so thats about right. Now when i turn the jeep on and its idling I get 13.58v is that ok? I thought it was suppose to be around 14.2 - 14.7v when the car is on. 13.58v seems a little low and thats with nothing on, no headlights, no radio, no fan/ac, so If i turn those things on itl drop a few more.

Hmm let me know what you guys think, as I dont want to go taking the alternator out if 13.58v is alright.

 

13.6 right off the battery with a DVM seems a bit low. One of my 90's idles over 14 with high blower and brights. A real meter right on the battery is a good start. The dash gauge is just a maybe reference.

 

I'm assuming its a 1998. How many miles? 13.8 is still charging the battery but it sounds like things are wearing out. I would do a quick check on belt condition and tension. You are going to have to do it anyway when taking out alternator. I suspect the alternator brushes as being worn.

 

It sounds like your alternator is starting to get worn as quneur suggested as long as you verified those readings with your multimeter.

I was worried that my alternator was failing because the gauge cluster on my 92 was showing 9v under load and 12-13 at idle.

I checked it with my multimeter and it showed 12.6 when off, and 14 at idle.

Turns out the gauge was a liar and according to some forum posts I've read, the volt meter on the pre-97 gauge cluster are notorious liars.

 

I would not be overly concerned, keep and eye on it though.

 

13.8 at idle is about normal without a load.

 

13.8 is fine for summer temperatures

 

Specially summer months. According to the guage im at 13.5-13.75 during the summer and winter its a lil past 14. The temp sensor below battery has a lot to do with it iirc.

 

Alright thanks guys, just wanted to double check with everyone and yes its a 98 xj with 154k miles I cleaned out all the grounds and nothing showed up yesterday but got the check gauge light on again today. Yes I used a multimeter to read the voltage. I was a lil concerned as I will be going to michigan next week which is like a 6-7hr drive one way. I dont want to get stuck somewhere haha. But yes its also summer here been around 80-90 degrees and humid.

 

what brand alternator do you guys recommend ? I was thinking bosch or denso when I decide to change it.

 

Whenever I need an alternator I go to a specialty shop that rebuilds mine. Much cheaper than a new OEM . One day turnaround unless he has one on the shelf then it's a swap. Stay away from the auto parts store aftermarket junk.

 

Rebuild is certainly an option especially if you know a good shop.

Buying a replacement, I try to stick to national brands like AC Delco, Bosch, Nippondenso, etc... but I avoid reman units like the plague. Burned too many times by remanufactured parts.