Alternator Warning Light and "Check Charging System"...

[lseguy]

..only under high RPMS (say 5k or more).

At rest, multimeter shows charging system putting out 14.26 volts.
Morning after the car has sat overnight, the battery (with car off) shows 12.36 volts.

When driving normally, all is fine. WHen at rest/at a light, all is fine.

Saturday I was cruising along in 5th at about 50mph then floored it. Tranny dropped down to third and power was fine, but immediately I noticed the alt and check charging system lights glowing. Came down off the gas, and the lights went out and all was fine.

THis morning, in SST mode, I had her in second gear, then smoothly gave her gas to the floor.. Redlined her, upshifted to 3rd gear. No problem.

About 4 mins later..I tried the same thing, this time alt warning light and "check charging system" light came up. Went off as soon as I dropped the RPMS down back to under 3k.

ALternator is a reman'ed unit put in about 60k ago. I honestly cant recall if I've ever replaced the battery, although I think I did about 3 years ago. Just cant find paperwork. Def a motorcraft battery in there. Battery terminals clean as a whistle and the cables are clamped on the posts firmly.

Serpentine belt is OEM with 145k miles on her now. Was waiting for 150k to do quite a bit of maintenance, including changing the belt. My first instinct is to replace the belt now and see if that helps. If it doesnt..no money lost.

What about the tensioner for the belt. Should that require replacing now?

 

[joegr]

It's your alternator. The brushes are flying just above the slip-rings at high revs. Either the brushes have worn down to where they are too short, or the springs behind them are too weak.
Brushes used to be a common item that you could get and replace yourself, since they are the main wear item in the alternator.

 

[lseguy]

Thanks Joey. How much longer do you think I have on this thing? I have a 220 mile roundtrip highway trip I pretty much have..to make tomorrow. Will I be good for that?
Other than the very high revs, no warnings are coming on.

 

[joegr]

Thanks Joey. How much longer do you think I have on this thing? I have a 220 mile roundtrip highway trip I pretty much have..to make tomorrow. Will I be good for that?
Other than the very high revs, no warnings are coming on.

Well, that's just about impossible to guess at. I think it could be anywhere from a few miles to a few thousand miles.

 

[jdmans101]

Thanks Joey. How much longer do you think I have on this thing? I have a 220 mile roundtrip highway trip I pretty much have..to make tomorrow. Will I be good for that?
Other than the very high revs, no warnings are coming on.

I had the same issue, Ignored it for about 2 months until I changed it. But everything can be different. If you have a volt meter I would keep an eye on it.

 

[scjmc]

I am on alternator number 5. They always fail in a differant way, but always eventually fail after the warning. Get a Motorcraft replacement....

 

[Lucky_Ls]

I’m experiencing the same thing. I found the thread that jdmans101 started back in July with the link to Quick LS’s thread (http://www.lincolnvscadillac.com/showpost.php?p=414151&postcount=2).
Question for you guys who have responded to this thread. Is it really just as simple as the instruction state to replace it? No really special tools? I guess a 3/8” breaker bar with whatever size socket but anything out of the ordinary?

 

[jdmans101]

I’m experiencing the same thing. I found the thread that jdmans101 started back in July with the link to Quick LS’s thread (http://www.lincolnvscadillac.com/showpost.php?p=414151&postcount=2).
Question for you guys who have responded to this thread. Is it really just as simple as the instruction state to replace it? No really special tools? I guess a 3/8” breaker bar with whatever size socket but anything out of the ordinary?

I wont say its an easy job lol, took me nearly 4 hours with the help of someone else. Its really tough to get the thing out and be ready to smash some fingers, but took less than an hour to get the new one in and everything back together. This was also the first time I changed it on the LS so next time it will go faster.

 

[lseguy]

Plan to replace mine in the next week. This will be the 4th alternator total. One replaced at the dealership 5 years ago with a Advance Auto rebuilt. Dealer charged $198 labor. That one failed in about a year. Got another from Advance under warranty..Pep Boys replaced in an hour for $99 labor.

 

[jdmans101]

Plan to replace mine in the next week. This will be the 4th alternator total. One replaced at the dealership 5 years ago with a Advance Auto rebuilt. Dealer charged $198 labor. That one failed in about a year. Got another from Advance under warranty..Pep Boys replaced in an hour for $99 labor.

Your first mistake was getting one that wasn't motorcraft. 198 for labor? holly crap it shouldn't have taken them more than an hour considering they work on these cars more than most.

 

[cammerfe]

There is not quite enough room for the alternator to drop out once unfastened. It'll be necessary to force it past some of the impedimenta once it is turned to the right position. I've done it four times altogether.

Doing it in the pits at Maxton, with a flashlight, was the least fun. But the last time was over three years ago, and this one's still working just fine. (I installed a voltmeter to monitor operation.)

KS

 

[tireman]

Pay the extra bucks for a new one

got a rebuilt duralast and it crapped out in 6 months. got a new one as replacement, no problems so far.

its your alt, on it's way out. Get a new one quick! When mine died, it took out the fuel pump too and fuses, some type of surge problem.

 

[lseguy]

gotta find an independent this time around. Pep Boys will only install their own parts...Just called Koons Ford/Lincoln in Silver Spring. $360 labor only to install Motorcraft alternator/Motorcraft serpentine belt