Hello all, the other day I was fixing a leak in the soft top. While fixing the leak I needed to keep the key in the 2nd position to let me move the soft top up and down. I noticed that when the key is in the second position with the AC and stereo off, the front of my alternator gets warm/hot to the touch. I would guess it to be around 150 deg F. The pulley is the hottest part, then the front of the case, and the rear of the alternator is only slightly warm. This bothers me because one, it is strange, and two, because it seems like that wouldn't be good for the battery. Car is a 2002. Battery is fine, engine was replaced recently. I would like to know if this is normal, and if not, what the issue might be. I am handy and can perform current draw tests, etc.

 

So, if I understand you, you do not have the engine idling when the alternator is getting hot? This is odd. Are you jumping or tapping voltage from the alternator?

 

There is no test for alternator temperature testing, so consider it normal. You can do testing of the alternator if you are concerned about its operation , otherwise don't sweat it. It will let you know when it doesn't work properly.

 

Engine is off. I am not tapping anything. Even though there is not a test for alternator heat, it still seems very odd, and an expensive waste of battery.

 

These are the diodes trying to do their job to prevent current from the battery flowing backwards into the alternator. Not unique to the S2000 according to my cursory Google search.. It may be normal or may be the result of bad diodes in the voltage regulator which is part of the alternator's rectifier.

-- Chuck

 

That makes sense. I am betting the diodes are in the front of the alternator since that was the hot part (if not, this would be even more puzzling). Still wondering if other people have this happen, or just me.