bizmackus Posted January 15, 2015 Share Posted January 15, 2015 Hey Everyone, I recently noticed my 99 legacy gt running very noisy. It is loudest in low rpms/and or idle and tends to go away above 2k rpm. The sound is a medium pitch groan, almost like its a bad bearing and its LOUD. Some days its louder than others. It also tends to quiet down after the car has been at operating temp for 10 min or so. I removed the alternator/power steering belt and the car ran normally with no hint of the noise. I also spun the power steering pulley and the alt pulley by hand- both felt smooth. Last night when parking in my driveway I noticed the headligts get way brighter when the rpms rise, and dim when the rpms lower. Does this sound like a bad alt? Or something else like the volt regulator? 99 LGT EJ25D 160,000 miles M/T Thanks! Link to comment Share on other sites More sharing options...
Zerohour Posted January 16, 2015 Share Posted January 16, 2015 Most part stores like advance and auto zone can test alternators. Pull it and get it tested. Link to comment Share on other sites More sharing options...
monkeyposeur Posted January 16, 2015 Share Posted January 16, 2015 Shops can test the alternator while it is still in the engine bay. I had mine tested at an alternator shop and while I was getting snow tires installed. The alternator shop said it tested fine but I didn't believe them so that's why I asked the tire shop to check it again. It started to smolder while it was on the lift, lol. Link to comment Share on other sites More sharing options...
cal71919 Posted January 16, 2015 Share Posted January 16, 2015 I think i read somewhere that a slight dimming of the lights is quite common on 2nd gens. Mine still does it even after a 140 amp alternator upgrade. Link to comment Share on other sites More sharing options...
corlon Posted January 19, 2015 Share Posted January 19, 2015 is the 140 amp alt a direct bolt on or did you just get a stock alt beefed-up? Link to comment Share on other sites More sharing options...
700watts Posted January 19, 2015 Share Posted January 19, 2015 From your description, I would go for bad voltage regulator. That's easy to test, just hookup a multimeter and test for potential difference. If it raises past 14v under throttle it's the regulator. The noise could be anything with bearings. It sounds like you've narrowed it down your the alternator. If I would to make a wild guess I would go for power steering pump. Link to comment Share on other sites More sharing options...
I Donated broknindarkagain Posted January 19, 2015 I Donated Share Posted January 19, 2015 The lights dimming and the groaning noise that goes away when you take off the alternator belt, I would say it is safe to guess you need an alternator. It might be smooth to turn by hand, but your hand doesn't exert the same force on that pulley that a belt does. On another note about dimming lights. A grounding kit is especially helpful on these cars. The factor chassis grounds on these cars suck. Google "subaru grounding kit" or look in the stickies for more info on it. -broknindarkagain My Current Project - Click Here COME AND TAKE IT "The only thing necessary for the triumph of evil is for good men to do nothing." Link to comment Share on other sites More sharing options...
cal71919 Posted January 19, 2015 Share Posted January 19, 2015 is the 140 amp alt a direct bolt on or did you just get a stock alt beefed-up? It bolted right in. I got it from Ace Alternators out of California, they have an eBay store. Definitely do the grounding mod and the additional power wire to the battery. You can buy a grounding kit or just buy the wire in bulk and make your own. Link to comment Share on other sites More sharing options...
clinton2003 Posted January 20, 2015 Share Posted January 20, 2015 Have you checked your ps fluid level. Does it get worse when you turn? The lights dim because these cars idle so low that the alt isnt producimg much power but when the rpm's rise the alt is producing its a 14v and everything is happier and brighter. Link to comment Share on other sites More sharing options...
bizmackus Posted January 23, 2015 Author Share Posted January 23, 2015 Update I replaced the alt and all problems solved While checking the battery/alt with a volt meter I noticed the alt was barely charging the battery when accessories and headlights were on. I also noticed the groan became significantly louder when I turned on the headlights. Thanks for the help everyone! Link to comment Share on other sites More sharing options...
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