Sintari

So these past few days, my battery light has been on. Once I rev to a certain rpm, it goes off. Now I am pretty sure its the alternator but I wanted a second opinion on this matter?

I figured I would go on and replace it before it leaves me stranded but I wanted to see what you guru's had to say about it first.

My car is a 5spd SC300.

chanh55

To test if it's your alternator that's bad start your car and remove the negative terminal from the battery. If the car shuts off then your alternator is bad.

over40driv

The battery light actually stands for the alternator, you need to have the battery tested to be sure if it is good or bad, fully recharged if its good then have your alt. bench tested then replaced if its bad.

TheMole

iTrader: (13)

If you are close to a Kragen Auto (Schucks, Checkers, etc.) you can take your battery to them and get it tested for free so that you can rule it out.

JDM

its very easy to check with a multimeter. Like sc300max said, go Kragan or something since theres basicly no way to mess up testing the alternator.

Mortal300

iTrader: (3)

heres the thing...usually the alternator dies becaus ethe power steering pump leakes onto the alternator causing it to eventually fail..

in my case that happened to me. i drove with that battery light going on and off randmly untilll the day came where im driving and my stereo shuts off....then lights go dim..windows slowly going up...it was like death slowly approaching...get the battery checked...its definatly ur alternator tho make sure u dont drive it cus u wud have to change ur battery...oh and check ur power steering pump in case...the lines as well they cud be leaking..who knows it wont show much cus the bottom plastic frame will catch all the fluid...

TheMole

iTrader: (13)

He says he has a 5spd SC300. The power steering issue usually applies for the SC400's.

TMaxxTim

Alternator, My sc300 did the same thing. Cheapest I found was a reman for $180 at autozone.

xknowonex

iTrader: (2)

sounds like its an alternator. that car is going to die soon so u need to get it fixed asap b4 ur stranded

no2faber

mine broke b/c of an oil leak from the distributor o-ring gasket. check for any stains on the alternator. usually, unless you're at the deal--and even they don't always check--most places will only change the alt. they don't usually investigate the cause.

If you see the battery light, act on is asap. lol. i waited and that didn't work out for me. you're better being stranded on your own schedule.

Mortal300

iTrader: (3)

yeah of course theres other problems i was just listing mine lol...yeah act fast or ur done. if ur not reading this cus ur driving ur car rite now. its over lol new alternator definatly

lphillips

LOL.. having the same problem on my SC4. It usually stays on for the first 5 minutes or so after I start it or until I get the engine up to 3k rpm. Just started happening yesterday. I took it to AutoZone and had everything checked. According the them, everything (electrical system) is working properly but the peak Alt output was only 52 amps. Thats barely half of what it should be. How could everything be "fine" if the alt is only pushing half the amps its supposed to! I know what I'll be doing this weekend.....

joshthorsc

Same thing happened to me. After a long drive home, I noticed my car felt weaker and there was this whinning sound and would get louder if you revved on it.

I don't remember if my battery light ever came on, but I bought a new alternator and and changed it. The sound went away and my car pulled like it did before. Well, turns out oil was dripping from the distributor O-ring onto the alternator.

If there's oil around your distributor or the metal plate behind it, you might want to replace that O-ring as well.

~Josh

Sintari

Alright guys, I replaced the alternator a fw months ago and it fixed the problem. NOW the problem is happening again except my battery light stays on all the time now. I know the alternator is good because I replaced it less then 3 months ago.

What do you guys suggest? And what is this oil ring you guys are talking about needing to be replaced? I'm not sure what you're referring too but when I look at my alternator, the back of it looks dirty but the front (where the brushes and pulley are) look brand new.

sonoramike

real bad idea - possibility for big spark causing fire from any flammable vapor hanging around, and the spike in the electrical system can smoke your ECU. This used to be a great test in older non ECU equipped vehicles but not a good idea on new cars