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Mike Puckett
05-27-2009, 08:12 AM
One of the guys in our local group has a 91 SC that ran on the original alternator until about 2003. Since then it has gone thru 3 replacements and we are putting the 4th one in tonight. The battery is a 3 year old Diehard. Is this just a reflection of the poor quality of rebuilt alternators or could there be a reason for this. The last one came from NAPA. He has no other electrical problems and battery life is normal.

Kurt K
05-27-2009, 08:33 AM
One of the guys in our local group has a 91 SC that ran on the original alternator until about 2003. Since then it has gone thru 3 replacements and we are putting the 4th one in tonight. The battery is a 3 year old Diehard. Is this just a reflection of the poor quality of rebuilt alternators or could there be a reason for this. The last one came from NAPA. He has no other electrical problems and battery life is normal.
I would like to think that NAPA carries better alternators than AutoZone, but I've seen way too many failures from rebuilt alternators. Unfortunately, I don't believe the OEM alternators are available from Ford any more so you stuck with finding an alternative.

Maybe you can find a shop to actually rebuild one the right way.

Kurt Sunday
05-27-2009, 09:32 AM
About 5 years ago a guy in the SCCoSW got some rebuild kits...I rebuilt mine - was not that hard to do.

Anyone know where to get a rebuild kit these days?

WhiteThunder
05-27-2009, 10:10 AM
The last one came from NAPA. He has no other electrical problems and battery life is normal.


I went through five or six NAPA lifetime warranty alternators in about as many months on my '97 4.6 LX. Turned out there was a internal solder failure in each one.

We finally sent one of the alternators to a local electrical shop to be rebuilt. No problems since.

When the alternator on my SC failed, I sent it to the same electrical shop.

eddie
'90 5-speed SC
'97 LX sport

Mike Puckett
05-27-2009, 10:59 AM
Interesting. It sounds like this is quite normal then. This one is under warranty so he's getting it replaced today and I'll put it in tonight. It went to full charge and output 17.6 volts.:eek: Plus after a couple of minutes it would get blistering hot. I've got a bad one in my junk pile so I'm going to open it up and see what's wrong with it. I've got another one that should be good but the stud for the output connection broke off. If I can get it apart I'll replace the stud. The original one in mine failed in the mid 90's. I replaced it with a rebuilt unit from Advance and it's still going strong. Oops, I hope I didn't just jinx it.:rolleyes:

KMT
05-27-2009, 12:14 PM
Have any of the replacements been used to recharge a battery while driving the car?

...or has the battery in each case been thoroughly charged before installing/connecting a fresh alternator and then driving the car?

Mike Puckett
05-27-2009, 12:36 PM
I don't know about earlier replacements but this time the battery was fully charged and was showing 12.8 volts on my meter with the motor shut off. I see where you're coming from, though. If the alternator had to try and charge up a seriously depleted battery it could be overloading it. I had just finished replacing the headgaskets for him and the battery light came on after test driving it. It then went off and on for awhile but then came back on and wouldn't go off.

TNOUTDOORS
05-27-2009, 01:12 PM
Mike,

Had a similar experience when I went through several alternators. Repeated trips to NAPA, etc. Turned out to be the lead that goes on the back of the alternator. Mine was split at the wire crimp. Just recently I discovered the wire at lead has hardened and become brittle vs. pliable as it should be. Pics a little blurry but check your lead for sure and they also updated the top lead (plug) back int the day.

the-big-e
05-27-2009, 02:17 PM
My silver 90 seems to be doing the same thing....:confused:

The ALT light is on, but it must still be charging the battery since it hasn't ever had to be jumped off.....:confused:

I'll check that connection this weekend.....

The last new SC alternator I bought was from Advanced Auto and that was right before the 2006 shoot out....

I've picked up over 20 SC alternators over the years and only three of them tested out to be good....:mad:

I did have the pulley nut on my white 90 come off :eek: and ruined the front casing and stator of the alternator....

Luckily, I had a spare bad unit and swapped the good parts out of it....

Took it to Advanced Auto and it tested out just fine......:D

David Neibert
05-27-2009, 03:24 PM
The alternator on my 91 (original) must be on it's way out, because I noticed that after driving a while the battery voltage starts falling from 13.9 down to as low as 11.5 volts and the alternator is getting very hot. I measured 260 degrees on the case after driving only 10 miles. Engine coolant temp was around 210. Battery light doesn't come on and the battery doesn't seem to be getting drained, turning on/off the headlights also has no impact on voltage.

David

Mike8675309
05-27-2009, 08:23 PM
This site has been full of folks reporting multiple replacements of alternators over the many years. I saw enough of them before I had alt problems 3 or 4 years ago that I didn't even bother with a store reman. I found a shop that would rebuild the alternator.

I've had two different alts rebuilt, and a starter by the shop. Never have had to bring it back. The cost has always been less than a reman at a local parts store. I think anytime you can find a shop that does the work themselves, the better off you are going to be.

kamakazie_1
05-27-2009, 08:56 PM
I've put 6 on my 95 in the last 7 years, from AutoZone, Discount, NAPA, and Bennett auto parts. All except the first one was with the lifetime warranty, which still sucks if you have to change the thing every year..

I've found an electical shop here in town, I'm with Mike I'm going to try the rebuild route this time, I know it's about to go again becuase it's pulsing the headlights again. The stores keep trying to blame the Alum. pully... Idiots..:mad:

RJ

TinManSC92
05-27-2009, 10:06 PM
i had the same problem with my old 89. 3 alts. on it. turns out the problem was the solenoid not grounging out properly to the body. a little rust prevented full contact making it seem like the battery was always dead. to think i paid a mechanic to play guessing games.:eek: had to figure that one out on my own.

Mike8675309
05-27-2009, 10:56 PM
i had the same problem with my old 89. 3 alts. on it. turns out the problem was the solenoid not grounging out properly to the body. a little rust prevented full contact making it seem like the battery was always dead. to think i paid a mechanic to play guessing games.:eek: had to figure that one out on my own.

Which is one of the reasons why a rebuild shop would be a great option. See they'll actually pull your alternator apart and diagnose the problem. They'll replace the failed part, and then replace their standard set of replacement parts as well. Once that's done, you ask them how it looked, and they'll suggest you check your grounds, or the line going to it from the battery or whatever due to the type of failed part they found. Or they'll tell you it was just old.

rickbtbird
05-27-2009, 11:22 PM
I suggest that every ground and high voltage connection you have be inspected and updated before you go any futher. Then See this post (http://www.sccoa.com/forums/showpost.php?p=730337&postcount=8). I've had this one in since the spring of 2008 with no issues.

90coug
05-28-2009, 01:08 PM
Here's a great link for alternator rebuilding, you've probably got the tools to do it.

http://www.type2.com/library/electrip/altreb.htm

Also, you can buy kits here it looks like.

http://www.alternatorkit.com


You’re not having a parasitic drain are you?

RockAuto says it has MotorCraft 110AMP alternators for $199.00. They don't mention they are remanufactured like the others.

Good luck and are there any stories of people throwing in one alternator and having it work?

pablon2
05-28-2009, 01:15 PM
Many times, my voltmeter (tapped into the feedback wire) registers 14.6 or higher when the engine is cold (if it goes above 14.7 the alt light comes on, and sometimes it briefly goes as high as 15.6!). Once then engine is warmed up, the voltmeter reads 13.5 as it should. I'm not sure if I should be concerned with the cold voltage rise. I'm okay with a cold voltage of 14.5, but not 15.6. :)

Mike8675309
05-29-2009, 07:49 PM
Many times, my voltmeter (tapped into the feedback wire) registers 14.6 or higher when the engine is cold (if it goes above 14.7 the alt light comes on, and sometimes it briefly goes as high as 15.6!). Once then engine is warmed up, the voltmeter reads 13.5 as it should. I'm not sure if I should be concerned with the cold voltage rise. I'm okay with a cold voltage of 14.5, but not 15.6. :)

I'd see if you can double check. It may be that your gauge is bad. high voltage can be as much as an issue as low voltage. More so to some of your external devices, but a problem none the less.