ok.....first time the battery light came on i took the alt and battery out and had them tested everything was fine. i was drive for a few hours then the battery light only came on when i accelerated and was above like 3000 rpm and like 25mph.....i changed my belt but as i was looking the tensioner was on mark b instead of between mark a and b......ive been searching the forms and i have the manual but im unsure what is wrong....not sure if the tensioner is bad or the pulley....nowhere could i find out what would happen if the tensioner was on mark be but i could find out about the crankshaft pully and it seperating but could not find out how to test that either.....any info would help please and thank you

oh its a 93 sc300 at 200+k

 

what's your charging voltage at 3000 rpms?

 

more than likely you have an alternator on its way out the door. Before you yank it, check to make sure the distributor or valve cover gasket is leaking as that is usually what kills these alternators. Fix any oil leaks above the alternator before replacing otherwise you'll be doing this every year or so.

 

If your battery is dying out, it's not being charged, alternator!

 

Thanks for the telltale will check at 3000rpm later.... Not saying that my alternator is not going out but my arrow on my belt tensioner pulley is not between mark A and mark B according to the manual but is ON mark
B could the tensioner seem bad?

 

Arm be bad***** not seem sorry

 

Pulley can be bad. But i would change the belt first

 

i have put i new belt on

 

Exactly this^^ When the brushes get oil on them they then basically turn in to cutting blades that cut in to the copper slip rings rather quickly at which point it is time for a rebuild, What you describe sounds exactly like an alternator going south as this is what mine did

 

Ok I need a o ring and just got it in the mail today.....next is alternator.....but I have another problem.....on the tensioner pulley the bolt is stripped on the pulley...cab I get a new pulled or do I have to buy a new tensioner?

 

are you talking about the bolt that holds the pulley in place? If so very unlikely as that is a reverse thread bolt and would be hard to source. I would just get a tensioner. also after you fix the alt. and the oil leak clean off your engine with a pressure washer and engine degreaser. That way you can check after a few thousand miles for any other potential oil leak sources. Good luck!

 

my battery light came on last night too, had the car 6yrs and this is first time i have ever seen light. batt is only a few months old and i have not had it tested yet, no leaks but altenator has 200,000 miles on it. can alternator be tested without taking it off car? any idea on what labor cost is to change alt? car is 96 sc 400. thanks in advance.

 

there is a tool my dad has made by blue-point i will get the name but it tests everything when you crank the engine, not sure how to test without taking it out, i guess the way you will know for sure is if you change your batter just swap it for a few mins with a buddy or something and if it's the same issue, i guess you can take it from their, anyone else care to help this guy out?