Weird voltage intermittent dropping
 

So I recently replaced the alternator on my 03 mustang gt as it was burning up and unable to go above 12 volts, now with the new alternator in, it's usually above 13.5 volts at anytime, if I idle for a while in a drive through or whatever it drops down to about 11.2, and the squeek I have in the front end (I think its the ac compressor) stops, once I drive for about 5 or so minutes I'm back up to 13.5-14 volts. Could I have received a faulty alternator?

ive gone thru 5 before getting a good one. yes its possible

Guy said he went through 7 alternators on my post and says he went through 5 on your post. Let people who know something comment please. Mr. White fox gt , If you can't answer a persons problem please don't GUESS. I don't think there is a prize for most posts.

https://www.motortrend.com/how-to/fa...rs-quick-test/

So your running voltage sounds good. But your idle voltage does not.

Are you running any power-heavy accessories?

Nope I'm not, when it drops it doesnt go up or down all accessories on/off, doesnt matter, just stays the same for some reason, thats why im confused by it haha. My idling voltage is good I'd say 60% of the time, never below 13.5, then every now and then it'll just drop and not go back up for a bit even when I start driving. I now have a new battery as the last one decided to eat itself (the cables and terminals wernt happy after the old alternator did its thing) so everything in the charging system is new, I even cleaned up grounds. Still happening though

Does the voltage drop only happen when you have the AC on or, it doesn't make any difference if the AC is running or not? Is the squeak present when the AC on or, it doesn't make any difference if the AC is running or not?

If the AC is on when either of these problems happen, it could be the compressor is locking up at idle (low refrigerant or bad bearing). If the AC is not on it could be a bad idler or tensioner pulley making he racket and locking up.

If any pulley is locking up, the belt will be very shiny on either the back or front ribbed surface from the friction and heat caused by a gummed up pulley.

Yes, go thru my posts and give me the award for 'most posts of not answering peoples questions'. I guess my custom user text should say useless poster plz ignore :icon_bowrofl: I just saw this highly constructive post. good luck asking the internet to magically fix your car for you using in depth clear and concise information from that bowl of water you call a brain. I dont need to be here or reply at all. yet here i am giving advice instead of childishly bickering because you arent capable of diagnosing your own ****box car..Try some of your own advice bub. I own and operate an auto repair facility and worked for ford for many years prior. Please show me your credentials and experience in the automotive field before attempting (poorly) to discredit one of the only people left on this board willing to take time to help losers like you. brb going to throw the alternator away for no reason off my 1000+hp mustang. i mean, at least it doesnt throw a p0320/340 code woohoo.. bitch

ac on or off it doesn't change it at all, I'll check the belt after work, now that it has warmed up a little the chirping doesn't really happen anymore

Your comment was misleading and a little shameful if you are an actual mechanic. I need no luck, I have my issue diagnosed with out this forum. Check my post for more info.

Should I keep buying alternators ? Ha ha

I checked out your posts, I'm hoping that's not what happened with my car haha, I have no codes, it always runs great, starts at -40 with no problems, just sometimes drops voltage, I'm going to get underdrive pulleys soon, if that solves the problem great, if not, I guess I'll try to switch out some of the idlers