Alternator Case Burning hot?! Need help

[Ken_86gt]

By any chance do you have Optima (like Redtop) batteries? They can draw a huge amount of power and take a long time to charge up.

 

[Tow4]

It sounds like the alternator is going full field. It would have a high current output unless there is an internal problem. If you have a clamp on amp meter, put it on the heavy output wire and see how many amps are being drawn. You can use an in-line amp meter if you don't have a clamp type. This will help determine if the problem is in the alternator.

If the current is high check the output voltage at the alternator. If it's high, the problem is in the alternator or it's external sense and it's lost the signal. Most external sense alternators will default to internal sense if they lose the external signal. If it's a bad connection in the sense line then the alternator will increase the output voltage to compensate.

 

[doghead]

Use an IR gun and tell us where you point it. Then take temp readings once a minute, for 5 minutes.

Then, someone can do the same with another truck, and you can compare.

 

[Commander5993]

By any chance do you have Optima (like Redtop) batteries? They can draw a huge amount of power and take a long time to charge up.

nope, just regular lead-acid batteries. But I have had an optima red top in another vehicle before, and I don't care for them. Yellow top is slightly better, but still would rather have a quality "regular" battery.

Use an IR gun and tell us where you point it. Then take temp readings once a minute, for 5 minutes.

Then, someone can do the same with another truck, and you can compare.

Thanks Doghead, but we don't have a IR temp gun, good idea though.
But the "problem" has been "fixed". See below:

It may be normal or a bad battery, just trying to charging up the battery? Put a clamp on amp meter on the wires to see where the current is going. If you see 80 amps from the alternator and 80 amps on the battery then thats all it is. You could also check the rest of the wires- you should be able to figure out where the current is going quite quickly.

Don't have an amp meter... that I know of at least. Just a small digital volt/ohm meter. Battery info below in one response:

Maybe...if you have a bad cell in one of the batteries. You could also take them to an auto parts store for a load test. The alternator would get hot if it is putting out a lot of current - this happens when there is an electrical load. It could be batteries, glow plugs, something else, maybe even some wiring issues seeing all the trouble you have been having. But if you follow the current with a meter you should be able to find your problem.

It is normal for the alternator to get hot when the battery needs charging. If the the alternator is only putting out a few amps after startup then the alternator may not be getting as hot as you think it is.

It sounds like the alternator is going full field. It would have a high current output unless there is an internal problem. If you have a clamp on amp meter, put it on the heavy output wire and see how many amps are being drawn. You can use an in-line amp meter if you don't have a clamp type. This will help determine if the problem is in the alternator.

If the current is high check the output voltage at the alternator. If it's high, the problem is in the alternator or it's external sense and it's lost the signal. Most external sense alternators will default to internal sense if they lose the external signal. If it's a bad connection in the sense line then the alternator will increase the output voltage to compensate.

Ok Everyone, You all were right. It was the battery.
After Dad and I discussing it this afternoon, and then several of you mentioning about the batteries too. My Dad put both batteries on charge, even though they were showing good voltage. After being on the charger for a while, we put everything back together, hooked the batteries back up this evening. Started the truck, ran for about 15 min, both alternators were now "normal" warm temperature. So I guess I just over-reacted yesterday, but I knew I had just done a bunch of electrical work and thought I might have done something, or if it had something to do with hooking the passenger alt and relay back up. I'd rather be cautions rather than to fry something... or a bunch of things.

We were planning on replacing both batteries anyway, just to have new strong one's which we know exactly how old they are. Since this happened, we're going to do this asap.

Thinking about getting either Interstate or maybe Deka, best brands that I know of.
*Update: Getting 2 Interstate Batteries today. From what I heard from many people, they should be the best batteries available.

In any case guys, Thanks for all your help!