waterproof alternator?

I have a '97 XJ with a little lift (3-3.5", 31's), and I take it off-roading from time to time.  Here in Michigan, we have more mud and water than rocks and sand for the most part, so there's a lot of times when you end up going through mud holes filled with water.  It seems that just about every other time I go mudding though, I end up killing my alternator.  This last time I avoided going through deep water/mud and managed to not kill it, but it would be nice (and more fun) to be able to do a water crossing without worrying about having to replace my alternator afterwards.  My brother ended up killing the alternator in his ZJ this time however...

So... does anyone know of an alternator that is more waterproof?  One that could handle a water crossing would be nice;  also mud-resistant/proof would be good too  I know I'm not the only one with this problem, I searched the forums and found some other posts from people w/XJ's also seeming to have the same issue.  Seems the alternator is mounted a little low in the XJ...

thanx!  

I've always wondered if water would allow enough current to flow that it would short out an alternator.

It seems like if you could stop the alternator from spinning/generating current until it wasn't submerged anymore. Maybe if it had a electric clutch, like an a/c compressor.

It's really too bad they didn't mount the alternator above the a/c unit. Would save a lot of hassle.  

Well, if it were sealed there would be no way to keep it cool. That's why they have little fans on the front. Water is not as much of an issue as mud. The mud can wear and coat the contacts inside causing it to not charge. Usually a good flush with a water hose while the engine is running is enough to get it working again. However, the longer you go without flushing the grit out, the more damage you do. So keep a jug of water around to flush it on the trail. Ultimately it will likely be much easier to keep the mud out of the engine compartment with some rubber flaps than it will be to get a sealed alternator to function properly.  

You could always look into putting a shield around it to help deflect the mud/water away from the alternator to minimize exposure.  
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thanx for the replies!  Only problem with shields/mud flaps is that they don't really help when you're driving into a mud-hole that's deep enough to actually "dunk" the alternator  That's always what seems to get mine... not the actual mud splatter from driving thru stuff, but the dunking that seems to be the issue usually.  I've posted a msg on another local off road forum and the guys over there seem to think that the solution is to replace it with a Chevy alternator.  From their info / experience, they say you can get a chevy alternator as wet or as muddy as you like, and they just don't stop.  So I'm trying to find more info on what's needed to do that.  Mine is still running for now, but maybe next time it dies I'll try to replace w/a chevy one  

Do some research on the voltage regulator. I think starting in '96, the first year of OBDII, the voltage regulator became part of the PCM. I know your '97 has the Electronic Voltage Regulator (EVR) circuitry contained within the PCM.

A Chevy alternator might charge ok, but the PCM may throw voltage related Diagnostic Trouble Codes. So if someone has a Chevy piece working on an older 4.0L, make sure you know how that will work with your PCM.  

JofCore:
Only problem with shields/mud flaps is that they don't really help when you're driving into a mud-hole that's deep enough to actually "dunk" the alternator  That's always what seems to get mine...

Ah.. true. I didn't even think about that because unless you have a snorkel by the time you get to that point the alternator is the least of your worries. But I'm guessing you have a snorkel.  
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So it's not a Jeep... sue me... it's still faster!

Questions? Comments? Concerns? PM Me!

:
Do some research on the voltage regulator. I think starting in '96, the first year of OBDII, the voltage regulator became part of the PCM. I know your '97 has the Electronic Voltage Regulator (EVR) circuitry contained within the PCM.

A Chevy alternator might charge ok, but the PCM may throw voltage related Diagnostic Trouble Codes. So if someone has a Chevy piece working on an older 4.0L, make sure you know how that will work with your PCM.  


Yeah, it might throw a diagnostic code, but that doesn't really bother me.  My check engine lite is perpetually set on since my downstream O2 is bad  I don't feel like spending money on a part that's essentially useless, so my lite is pretty much on forever  So another code won't bother me much.

I'll find out though soon enough probably;  My brother (who recently killed the alternator on his ZJ) tried the hose it down trick to see if that would bring his back to life, but no luck.  He's got a GM alternator off a 350 that he has sitting around that he's going to try to wire up on his ZJ and see what happens.  So we'll find out what happens then.  My alternator in my XJ is still working for now (it was replaced a couple months ago so it's pretty new still).  It seems to have survived the mud for now (it's got a bit of mud covering it though since my last muddin' trip... as does the rest of the engine )  

JofCore:
Only problem with shields/mud flaps is that they don't really help when you're driving into a mud-hole that's deep enough to actually "dunk" the alternator  That's always what seems to get mine...

Jp Web Editor:
Ah.. true. I didn't even think about that because unless you have a snorkel by the time you get to that point the alternator is the least of your worries. But I'm guessing you have a snorkel.

Actually I don't have a snorkel yet... but the alternator is so far down on the engine that you can easily dunk the alternator w/out getting water/mud into the air box.  Makes it easy to work on / replace, but it's also real easy to get it wet/muddy when you're plowing thru a deep mud puddle

Like I said though, mine is OK for now, it survived my muddin' the last time.  I need to wash out my engine sometime soon though, there's a lot of mud in there...  Hopefully it will keep working for some time to come.