On the way into work my check engine light came on then turned off and I saw that the alternator voltage was low, around 12.5v or so.  I tested it running at work and it was about ~12.5v.   I then noticed that the positive battery terminal has melted on the cable coming straight from the alternator.  Would an alternator going out cause this? Bad connection? Low battery electrolytes  Any ideas?  The alternator has never been replaced.

 

Thanks!

12 minutes ago, Feral said:

Bad connection?

I'd put my money on a bad/loose connection.  That type of connection cause high resistance and high resistance causes heat.  The higher the resistance, the more currant to overcome it, the more heat.

You sure it’s not from the starter? 

I vote  for dirty terminals. Most likely would say it was during starting the engine and being it takes about 500 to 700 CCAto turn over. Being the connection was dirty and high resistance yup it will melt lead.

@IBMobile and @Mopar1973Mancouldn't have said it better.  I would disassemble, inspect and clean all of your battery connections and battery grounds.

 

- John

Make sure to clean all rust and black oxidation off the terminals.

 

If you want to never clean them again just keep them moist with engine oil. That's all.

Thanks for the quick replies guys!  That's good news, I will clean and inspect them all.  I have some new terminals in the mail to replace the melted one.

This happened on my truck with cleaned terminals and it was a shorted alternator.

 

This happened on my work truck the day after running the grid heaters and both seat heaters on high at the same time. I wanted to see how much the alt could take.

 

When chasing a new or rebuilt one, I told the old guy at the counter, ''please, no Ultima brand rebuilds", as they had horrid reviews. So I let him talk me into Ultima's premium rebuild convincing me they have changed their ways and their premium rebuild is actually a good one. He put it on the test stand to show the level of AC ripple , which was very low. Over a year later and I'm on the seat heaters again but, this time after the grids are done. So far so good. Need to test the AC level again now though.

The biggest thing that made a huge improvement was the W-T ground wire mod. Ac ripple is now about 11mV AC. Since then I quit having alternator issues completely.