Alternator, How hot should it get?

[diveman05]

Good morning everyone, I'm one of those start the boat and lift the "hood" kind of guys to check everything everytime. I was going over temperatures with my IR gun to make sure the manifolds and everything were equal (recently put in a new impeller) and i stopped on the alternator. It was registering 190-200 degrees. This was after running for 10-15 minutes or so and after coving out all night with some lights on and radio going. So there was deff. some battery draw down over the night.

Never checked an alternators temp before and doing searching there is a lot of all over answers. Anyone here have a good idea?

If it matters its a 2003 Merc. Mag 350 MPI serial 0M620680

 

[Fun Times]

On basic average I'm used to seeing them run in the 125 - 160 range but have seen them go as high as almost 200 on engines around your year...... Replaced an alternator on an 2004 6.2l engine last year when it would get to 230 within 5 minutes and seemed to max out at 325 while idling and no accessories on . :flame:

An over tightened serpentine belt plays an affect with heat too.

 

[Bondo]

Ayuh,.... Alternators run Way to hot to touch,..... Never checked one with a IR thermometer,...

 

[diveman05]

On basic average I'm used to seeing them run in the 125 - 160 range but have seen them go as high as almost 200 on engines around your year...... Replaced an alternator on an 2004 6.2l engine last year when it would get to 230 within 5 minutes and seemed to max out at 325 while idling and no accessories on . :flame:

An over tightened serpentine belt plays an affect with heat too.

Thanks Fun Times, I'll check it a few more times next time I'm at the lake. Volt meter seems to be steady and good, so I'll keep an eye one it. At least its right at the top of the engine and a pretty simple replacement if it goes. Thanks again!