I replaced 9 or so alternators before I finally got one that hasn't failed inside 6 months. So far still putting out 14.4v just like the day I installed it. After all the issues with alternators I've had, not a single one has been because of oil contamination, they just died for seemingly no reason. My current hypothesis is that the Alternator industry saw that the 4 cylinder model was rated for 85A and decided to run with that for all models. If you look closely at the spec sheet for the aftermarket alternators you'd generally buy from the local parts store, they are all rated 85A~90A and normally refurbed. I went out of my way this time to get a 100A brand new unit and finally it's holding strong. No more flickering lights at a stop, no more dead batteries. IMHO, even the engine is running better now.

In addition to the oil soaking issue most people run into, there is definitely something hinky going on with alternator manufacturing in regards to the Montero Sport.

EDIT:
I am a forgetful liar, make that 10 or 11 alternators, one did in fact die to a fountain of transmission fluid landing on it because I forgot a hose clamp once.

 

Holy KaMollie Valkarian! You go thru alternators like Babe Ruth went through Home Runs. Thats a real good tip......If I ever have issues with my 94 Monty alt., I will try to up the amps to 100.

Hinky Dinky........what are those alt. Mfg.s smoking on Friday afternoons? Maybe all your alts. were made on Friday afternoons......and did they have the Jamaica stamp on them? Irie Mannn! Mellow out....No worries.....a few less windings, a few more windings, who cares......he heee heee, tok, tok, tok.....slap in these used brushes....he hee heee.....pour some Red Stripe on em......tok tok tok.....Bob Marlie would be proud of us......were all Buffalo Soldiers, sending defective alts to the heart of America.....Buffalo Soldiers, tok, tok, Irie Mannnn!

 

Turns out my battery was actually bad. We had a cold snap and I noticed the car was hard to start after installing the new alternator. Then it died right after starting when I went and got gas. So I bought a cheap value battery from Walmart for $55 (group 26, 525 CCA) because I didn't want to spend money on a battery if that wasn't it. Since installing the battery I have had no issues. Time will tell. Next I'm going to change the spark plugs like my friend recommended. If they look bad I will reply to this thread.

 

analog......Speak of bad spark plugs, check out this picture. This is absolutely the worse spark plug I have ever unscrewed from an engine in my entire life. Was in a 99 Suburban 5.7 with 160k on the clock that I bought last year. She has been running fine, except for a couple "crank but no start" issues last month. Finally had time to do a 100% tune-up----MAF, Throttle Body, IAC, Speed Sensor, etc, and the very first plug I pulled out on the right front was this one. The 7 other ones were still "ok", just normal plug wear.

Hunter......Does this beat any of the plugs you have ever pulled out?

 

Hands down - YES. That is the worst I've ever seen even on the most abused and neglected piece of farm machinery. I can't believe it stil ran for you in that condition.

 

Hunter.......Funny....I thought you might like that picture. I believe the ceramic around the electrode tip developed a crack, and then chipped off. This allowed the spark to shoot side-ways to the threaded part of the plug, and I guess that with time this poor spark allowed all that carbon to grow. Probably half the time there was so weak a spark (or no spark) that there was no combustion in the cylinder and when it did finally ignite it allowed more carbon to build up? Im surprised that no "check engine light" ever came on, for a mis-fire, or a rich condition in the catastrophic converter.

But the good thing is that after finding this "Fukishima" plug, all the other 7 were pretty good.
I think I will go check the Ohms on it and see how the resistance compares to the others.

 

Dang!! That is pretty bad.

Well of course yesterday I posted that saying all seemed fine and I had a bit of hiccuping this morning. Nothing like I had mentioned previously where the entire engine would stall, but it seemed like maybe there was something misfiring. I will be replacing the plugs this weekend hopefully - other projects preclude me from digging in at the moment. I honestly don't know when my plugs were last done, it could easily be over 100k miles.

 

analog......Yep, so bad that i might have to make a wooden frame and make this a display hanging on my wall. Hope yours are not this bad. Here is another angle where you can see the electrical arc path that left an imprint as it found a way to the side of the plug:




If I were that front piston, I would not be so keen to look up past my rings and see that plug action going on (or lack of action).
I would be screaming "Scotty, we need more power.....give me more power".
Scotty would be yelling back, "Aye coptain, but Im giving you all Ive got!"

 

StudebakerHawk, the photos you posted are just like illustrations you'd see in some training manual showing the old/malfunctioning plug compared to a good plug. Quite impressive. Do you know how long those were in there?
BTW, I don't think you'd get that much carbon buildup on the plug from just gasoline and misfire. I suspect you might have weak rings in your pistons or leaky valve guides on the intake valves.

 

Hunter......Thanks for the positive feedback on my "picture-taking"....not too bad for a 15 yr old digital camera that has seen better days. This Suburban has the 5.7 and has 160k on the odometer. The original owner did not want to pass-on his old maintenance records, so I have no idea if he ever had the plugs changed.

The rig runs great, and does not burn oil that I have ever noticed. I should have done a compression test on all cylinders when I had the plugs out, but honestly it was a pain and a tight squeeze getting to those rear plugs. If I notice any performance issues, a compression test will be on my "to do" list. I am burning strictly Non Ethanol gas now. Do you think carbon build up is more likely with Ethanol?

Also, the Throttle Body, EGR, and related components were pretty darn cruddy, and may never have been off and cleaned......maybe with those so dirty, the carbon on the plug would build up faster too.


Throttle Body, Engine side:







Throttle Body, Air Intake Side:




As clean as I could get it, Engine Side: But now you can see those checker-board lines on the butterfly:




And since most here dont want to see a GM Throttle Body, here is a picture of a dirty and clean 1994 Mitsubishi Montero Throttle Body: