Hot alternator

[KLF]

What would make an alternator run really really hot?

The aftermarket "Champion" alternator that I had to buy on the road 2 years ago quit working last week, so I grabbed one of my spares out the garage, the one from the '87 turbo truck that I parted out. It's an OEM alternator, but it was covered in nasty greasy goo, I think the PS pump was dripping on it. I hosed it down with SuperClean, then a bunch of brake clean. I checked the brushes, they looked good, so I took it to a local shop and they said it tested fine.

Installed it today, seems to work OK but it gets uber-hot, like too hot to touch. I doubt it's gonna last long. It doesn't make any noise, so I don't think it's a bad bearing.

Never heard of an alternator getting hot, and I don't have any big draws that would make it work hard. Any ideas?

 

[WristPin]

the diode rectifier plate is probably whats making the heat.
I figure since its what swaps all the AC to DC, you know.


????


any time i have an alternator bench tested, I run it at least 5 times, just to make sure.

 

[KLF]

Hmmm... maybe I'll pull it and put in my #2 spare.

Any tips for getting that sucka out easy? I always start by pulling the radiator, which seems extreme, but it sure makes it a lot easier. Don't want to go thru all that again.

I also yanked out all my AC stuff this time, prepping to install one of the Yorks I picked up the other day. Anybody need any AC parts?

 

[WristPin]

you are workin way too hard.

i can R&R an alt in a 22R/E in 30 mins.


I use a plug that fits around the inlet of the radiator. hose pinch off pliers, for the hose. saves time drainnin and filling it back up.

loosen the front part of the lower hose. use gear wrenches for the lower bolt, and just a few turns with the upper bolt. gettin the plug out takes the longest somtimes. but since you just had it out, it probably will come right out.

obviously theres a little more, but I explained the best approach.

 

[2ndGenToyotaFan]

The bolt that mounts the hard U that the lower rad hose goes to on mine is missing, making it pretty easy to slide the alt out without opening the cooling system. You may want to look into that. Hehehe

 

[KLF]

OK, Jerod wins the prize for the "fast alternator swap" tip.

I did some more testing with my hot alternator today, just sitting idling for a few minutes it got up to 210 degrees. That's just not right. So, grabbed another spare off the shelf that I knew was good, swapped it out. Took all of 30 mins, including gathering the tools and several trips back inside to get a few more. Th trick is to unbolt that rigid U-shaped tube, it's only 2 easy bolts. Then the whole lower hose will move out of the way just enough, it's still a tight squeeze but if you keep spinning the thing around it eventually falls out. Didn't have to drain the coolant, didn't even have to remove the intake tube that runs across the front of the engine. MUCH easier.

This one stays nice and cool.

 

[2ndGenToyotaFan]

Right on! Glad it went fast, and that the "new" on is not getting hot... Have you looked into the Hot one? To see what may have been the issue?

 

[Bogo]

could be an internal short in the windings.

 

["N8"]

If I had to guess the first thing I would check would be the main shaft bearings for the alternator, and then possibly take the spool out and make sure that there is enough clearance with the outside magnets.

dono past that.