4 alternators in 3,000 miles

Holy crap! Tonight I just burnt up my 4th alternator in the 3,000 miles I've owned my heep. I sure am glad that i'll be replacing this one and the last one at autozones expence (the lifetime warranty was definitely worth the $5 difference). I guess I do have a question, do you think that mud is really the cause of this? On the last one, I found all the ball bearings at the rear of the shaft out of place and completely worn (haven't taken this one out yet). Has anybody came up with anything to prevent this, jeep really shouldn't have put it down there even though they run better when in cooler air but I thought jeeps were designed with the off roader in mind. This is my daily driver and weekend off road warrior so I really need a solution to my problem that doesn't involve some ridiculous way of moving it to the top of the engine bay (unless there's an easy way to do it). It seems as if every time I burn one up, it's within a week or so of pretty decent mud exposure, but is it possible that it's anything else besides mud? I am starting to question whether or not it can make a 1300 mile trip under heavy load when moving back to the great state of Minnesota come September 18. Thanks in advance for your replys.
schmels3

the mud might be the cause of it, but it might be something else entirely. Bent mount/bracket, sh!tty series of alternators, etc...

I'm no electronics expert, but usually mud and alternators don't mix. When you say you're exposing it to mud, can you explain more? I find it hard to believe you've gone through 4 in so short a time without something else being to blame.

I have often thought Jeep made a mistake by mounting the alternator so low. Seems it would have been much better to swap locations with the ac compressor. Both for off roading and maintenance in general. But that's not the way they came. Just for frame of reference though, I've had my '01 since new and it has the original alternator. And my 98 ZJ and TJ both have their original alternators too. Have only had to replace batteries on all of them. But none of the three have ever been exposed to heavy mud.

The Cherokee came from the factory with a thick rubber shield that bolts up on the undercarriage just aft of the radiator, keeps dirt, mud, water from fouling the alternator and PS pump. Most people lose it or don't reinstall it after working on anyhting from below, but you might be able to dig one up at a pull-a-part yard.
You're sure water/mud contamination is causing alternator failures? Tried going to a heftier alternator, like a 100 amp?

One more once...

Most "chain stores" ('Zone, Advance, Checker/Schuck/Kragen) buy their alternators in Conex boxes - for about 30% of what they get sold for (probably less.) Most are "(Re)Made in China" as well.

That "lifetime warranty" is a gamble on their part - they're betting that you'll get one that will work (hopefully long enough for you to sell the car,) and you're getting a lifetime warranty betting that you'll come out ahead and be able to swap the thing (when you need to. You're probably going to need to.)

Shonky rebuilds, with shonky parts - and they're bought cheap enough that it's fairly "cost-effective" to offer a warranty, and they usually come out just a bit ahead. Granted, if they'd offer better parts, they would come out farther ahead on the warranty, but that's what happens when the "China Price" becomes a driving factor.

Oddly enough, I deal with a small shop, I pay less for my parts, I do not get a lifetime warranty (Rod gives a year, as I recall...) but the best warranty is one you don't need, and I've not needed a warranty from Rod.

So, who's coming out ahead? You've got a lifetime warranty, so you don't have to buy replacements - but you still have to waste time installing them, don't you? I haven't had to bother - my alternators and starters just keep running (and I deal directly with the man doing the rebuilding, so I know just who to bitch at when it doesn't work. Probably why they keep working - Rod's about my size, but I've got a louder voice when I need it, and I've not needed it with him...)

5-90

I do believe this is a 100amp alternator. But of course, when I bought the heep the plastic "engine guard" or whatever its called, was not there (probably some jacka$$ at a lube shop never reinstalled it). Anybody have an extra one? My best guess is that the mud is causing this especially because the guard is missing.

My lowest-rated Delco is set for 140A, and I don't have splash shields on any of my rigs. Water, mud, all sort of crap get into there - and I hose it out later.

Problem solved.

5-90

What year engine is this? Auto Tension system or old? How tight are you making the belt?

That splash guard if I remember right is like $17 or $25 from the dealer. I also recollect someone here who made a template and was planning on making a more armoured solution. Did not read any more about it so I don't know if it was done. I still have mine in my 98 but the only reason it's still there is because the front factory skid keeps it in place, it is ragged out though.
As for the location, check out the newer TJ's, they flipped the alt and a/c top to bottom then the used a smaller compressor and put the alt and a/c both on top and an idler down low. That setup really got my attention because one guy in bmja put his onboard air compressor down there which allowed him to keep his a/c. I plan on moving my 97 TJ's alt up top and putting a compressor down low once I start my TJ build this winter. I don't have a/c in it so the top position is already open..

sorry, my bad - 89 xj 4.0 4wd dana 35 np231. I'm leaving approx. 1" of flex to the belt. Im guessing its the mud seeings how the original and all of them expired shortly after getting caked in mud
schmels3

1" of flex may be a bit much.

Best way is to get a belt tenion gage (Krikit, should be available from NAPA. Search here, there's information.)

Second best would be to tighten the belt and check it thusly:

Grab the belt in the middle of the longest free span, and try to twist it through 90*. You should just be able to give it 1/4-turn - more is too loose (and you won't make full power when you need it) and less is too tight (which will cause bearing failure - probably the forward bearing, less likely the rear.)

5-90

Thanks for the info on the splashguard, i figured the stealership would want some outragous green for it so I'll have to look into that. As far as tension, i believe when i installed it last i did the 90* check and got about that, but im not positive. Ill have to check on it all tomarrow, i've got to be up at 530 for another 14hr day. Thanks very much for everyones input, very much appreciated!
schmels3

NAPA if possible. I just replaced the 4th water pump from AZ in less than 5K miles, and I'll all done with that. I put in a Hesco HV pump, and it cost $130, but I won't ever have to GO THERE again.

As for alternators, you've already dropped big coin- so gop to 4WD parts, and but a "Mean Green" unit for what you've already spent (with warranties), and be done with it.

For the rubber shroud, go buy some rubber sheet stock (oh yeah, from AZ!) and cut to to fit in the open space below the alternator. Somewhere in their "Help!" section, they should have some plastic "snap-tabs", to fit in to open frame holes left from the stolen rubber sheet installed OE.

AZ is good for "stock" items, that you have to modify for use, but for replacement parts that will last, they suck.

5-90 said:

My lowest-rated Delco is set for 140A, and I don't have splash shields on any of my rigs. Water, mud, all sort of crap get into there - and I hose it out later.

Problem solved.

5-90

Click to expand...

I do the same as 5-90, when they get packed full of mud I wash them out. I've found really hot water works best (it evaporates quicker) and a little air to blow out whatever is left over helps. Splitting an alernator isn't that big of a job. Especially the second time around after greasing the bolt threads. You don't have to take the pulley off to take the back off.
I've never had water hurt an alternator much that I've ever noticed. Though the bearings are rarley water proof, just water resistant.
Mud will get under the brushes and cause failure. Washing the mud out before it gets a chjance to work as a abrasive very much, really helps save wear and tear on the brushes, slip rings and other rotating parts. Mud also holds moisture and where water will evaporate fairlly fast, off of a hot alternator, mud dries slower and holds moisture longer.
If you have pin hole leak on the radiator, top right, under the shroud (which is pretty common) the coolant spraying onto the alternator seems to fry them fast. Coolant is a pretty good conductor and seems to cause serious shorts, which causes regulator or diode failure.
Getting the mud out of the alternator is a regular part of my after mud maintenance. Along with cleaning out the brake drums, cleaning electrical connectors, a good undercarriage high pressure wash and a good grease job. Regularly getting the mud out of the mud traps under your XJ, will really increase the service life. Anyplace the mud sits for months or years is gonna be the firat place to rot out, especially if you live in snow/salt areas.

Although some alternators tolerate mud better than others, it's still best to keep the mud out with good splash shields.
Good splash guards also improve cooling on the highway by reducing air pressure under the hood, the result of which is more are flows through the radiator.

http://www.4alterstart.com This place has good prices. If you had a later model, there is a high amp version really cheap. As far as the engine splash guard, check EricsXJ's here (post 5): http://www.jeepforum.com/forum/showthread.php?t=43508&highlight=splash+alternator

You might want to check the ballast resister. I had the same problem on my 88. I would cover that thing with mud every weekend. Over about 4 months I went through 4 alternators and 2 batties. If the ballast get caked mud in the connections, the alt. will cause a backward charge loop, at least that is what the shop said. It is the little white brick thing with two wires on it. I believe that it is somewhere near the airbox, mounted on the fender. Other than that I did start washing my alt. after I went mudding. goog luck.

Bunookana said:

You might want to check the ballast resister. I had the same problem on my 88. I would cover that thing with mud every weekend. Over about 4 months I went through 4 alternators and 2 batties. If the ballast get caked mud in the connections, the alt. will cause a backward charge loop, at least that is what the shop said. It is the little white brick thing with two wires on it. I believe that it is somewhere near the airbox, mounted on the fender. Other than that I did start washing my alt. after I went mudding. goog luck.

Click to expand...

That's a fuel pump ballast resistor - it was added in 1988 for NVH issues (Noise, Vibration, Harmonics) and was a voluntary recall for 1987. It can be removed (just put in a jumper lead, or splice the wires together) without any trouble - the only effect will be slightly more fuel pump noise from the back.

If you spend a lot of time cleaning it out, simplify matters and be quit of it. I've deleted it on two vehicles, and it was never on my 87XJ to begin with...

5-90

so can it be removed in a 90 xj?

It can, as I recall, be removed on ANY XJ. It's not involved when the engine is started - just when running.

Brief test - put a jumper lead in place of the resistor, just to make sure. Drive around like that for a day or so (keeping an eye out...) before you physically remove the ballast resistor. That's what I did.

As I'd said, it was added later, and was a voluntary recall for 1987, so it doesn't affect driveability or safety. Or emissions.

5-90