Platinum_Racing Posted October 6, 2009 Share Posted October 6, 2009 So today I got in my car to go to work and I noticed on engine startup that there was a distinct whine coming from under the hood. First thing that popped into my head, within seconds, was "Time for a new alternator." So I get to work, 9:45 rolls around and it's time for the Roach Coach break at the shop. I buy a snack and grab the multimeter. I put the meter on the battery and crank the engine. At idle it's running about 12.3 volts, exactly the same with the engine off. I turned on the rear window defroster, high beams, heater, radio, and hazard lights. The voltage dropped to 11.5 volts. Not a good sign. Good thing I have a good battery! If I goose the throttle I could see about 13.2 volts, nothing spectacular, but it tells me the alternator is failing, especially under load. I go home, take the alternator out. 4 minutes later I'm in the car on my way to the autoparts store. I usually take my alternator to HUB Automotive for such things, since they rebuilt starters and alternators at a decent price and they do the best job I've ever seen. Unfortunately they couldn't have it all done before Wednesday, so I had no other choice but to go to crap-tastic AutoZone. Just for giggles, I threw the old alternator on their tester. Failed every test. I got the new one, and had the sales lady throw that one on the tester as well. I've had a bad experience with "Duralast" alternators in the past, and I'm not so eager to deal with those problems again. It passed, thankfully. $123 later I'm on my way home. I got home, 8 minutes later the car was back together. My headlights don't dim at all when I put my windows up, or turn on a blinker, or the heater, I'm happy... At last. So that was my day, started off crappy, but ended alright. Link to comment Share on other sites More sharing options...
987687 Posted October 6, 2009 Share Posted October 6, 2009 I wonder if my alternator is failing. my headlights dim under about 1k RPMs. Idle voltage is about 12.2 to 12.4v, and doesn't crank up till over 1.5k RPMs. Then rarely do I see 14.4 Link to comment Share on other sites More sharing options...
Platinum_Racing Posted October 6, 2009 Author Share Posted October 6, 2009 That's what mine was doing. It also will make a whizzing noise, especially when it's cold or under load. If you want to check it, turn on the rear window defroster, the heater full blast, the high beams, the hazard lights, the radio at a decent volume (Don't blow the speakers), the windshield wipers, and anything else with an on/off switch and see if it drops below 12V. If it does, the alternator is without a doubt on it's way out. Since it's already only putting out 12.2V at idle then chances are it's gone. Take it out and bring it somewhere with an alternator tester. It took me 3 minutes to get mine out. You could even do it in the Wal-Mart or AutoZone parking lot. Just bring a 10MM wrench, a 10MM socket, a 13MM socket, and a 1/2" drive ratchet. Link to comment Share on other sites More sharing options...
987687 Posted October 6, 2009 Share Posted October 6, 2009 Yea, I can get it to drop below 12, then it actually raises the idle until it just gets over 12v. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.