Hot alternator

toddao · Post by **toddao** » Thu May 14, 2009 7:12 pm

I tried out a used Alternator that I inherited today and the thing started emitting smoke, though it seemed to be charging too. Also it got very hot. I removed it and discarded it, heaven knows what the smoke was - it's been sat in a garage for years.

So I put the original alternator back which as been working well for six months and I noticed for the first time how hot it got after five minutes running. I know that alternators do run hot but how hot is normal? I've never considered this. The battery also was run down so maybe this was contributing?

pitman · Post by **pitman** » Thu May 14, 2009 10:04 pm

I don't know how hot becomes an alternator normally but the smoke came probably from the belt when the alternator is jamming.

I had once an alternator making a metallic noise. A few days later, white smoke came from the alternator belt.

DLM · Post by **DLM** » Thu May 14, 2009 10:51 pm

Standard Valeo alternator not too difficult to take cover off if you want to check for scorched innards. Does the bearing revolve freely, though?

nige! · Post by **nige!** » Fri May 15, 2009 6:28 pm

if its been standing a while it would be the friction of it trying to unseize itslef and probably the friction on the fan belt itself.

toddao · Post by **toddao** » Sat May 16, 2009 12:22 am

I charged the battery up overnight ( it's a lovely scavenged BMW battery that has a little window which changes colour : green, charged. Black, under charged. White,F'ed). And the alternator didn't run so hot ( only hottish). The smoking one is in the pile of cactus alternators awaiting the visit of Roland Kaiser the scrap dude..

Like that old song : No Charge.