car battery/alternator question

[dabuddha]

1998 Mercury Grand Marquis.

My battery light has been flashing on and off randomly for the past 6 months or so. I've had it "tested" at advanced auto parts and each time they said the battery and the alternator tested out fine.

Well this past weekend, my car was completely dead in the morning (no lights on nothing). I pop the hood and looked at the positive cable connector and it's corroded pretty badly and it was split. Meaning the ring that goes on the positive terminal was broken. So figuring that might be why the light has been flashing on and off, I cut off the old connectors and replaced both of them with new ones. Unfortunately, my light still keeps coming on and off while driving after doing this. I'm not sure what I should be checking next and could use some advice!

TIA!

EDIT (10/17/2011)

Didn't want to create a new thread since I had this one laying around from earlier this year. Same car, I ended up getting my intake manifold replaced about 3 weeks ago (old one had a huge crack in it). I have a new car and have moved this car into the backup slot. So I go out once a week and start/run the car for about half an hour.

I went out yesterday for my weekly starting and the car wouldn't start. The lights all come on and are bright. When I turn the key, all I hear is a rapid clicking but the engine doesn't turn at all. I then hooked it up to my camry thinking it was my battery but after waiting about 5 minutes, I tried to start the car and it just rapidly clicks still. Is it my starter?

 

[jlee]

The light is likely coming on when your charging system's voltage drops below a specific level. I am guessing it's the alternator...do you have a multimeter to check voltage when the car is running?

/waits for more electronically gifted Garage people

 

[dabuddha]

I don't but I can borrow my neighbors. I read somewhere that the battery should show 12.5 volts when the cars off and about 13.8 - 14.5ish when it's on? And when I turn on all my crap, I should see a slight drop before seeing it come back up to 13.8 - 14.5ish?

My numbers are probably off lol

 

[Lotheron]

I don't but I can borrow my neighbors. I read somewhere that the battery should show 12.5 volts when the cars off and about 13.8 - 14.5ish when it's on? And when I turn on all my crap, I should see a slight drop before seeing it come back up to 13.8 - 14.5ish?

My numbers are probably off lol

This is pretty much correct. With the car running you should be above 13.5v at least up to about 15.5v or so., with it off it should be around 12. It should remain in this range even with load. You are correct voltage will drop until the system compensates for the new load.

 

[Vette73]

Could be a flaky Voltage Regulator or brushs wearing out.

You would need to test it when the light is on/flashing to see what is going on.

Also check the wiring at the VR on the back of the alt. I have seen many burn out on Fords.

 

[LordMorpheus]

I have a 1997 Town Car (more or less the same mechanically) and I've replaced my alternator a few times. The second time it failed, it behaved a lot like yours is doing now. The battery light would come on and off. What was happening was that the alternator was just giving up entirely for spells here and there. It got progressively worse - when I finally went to get a new one I drove a mile or two on just my battery, which was really interesting as all of the electronics in the car started to switch off as the battery started running down. I was lucky to make it.

The good news is that the alternator is dead simply to swap on our cars. The first time you do it, budget half an hour if you've got the tools. At this point, I could probably have my car running with a new alternator inside of 10 minutes.

 

[dabuddha]

I've never done anything as mechanically "advanced" as changing an alternator but it looks pretty easy on our car. It's literally on top of it all!

 

[Vette73]

^

Yea its not to bad.
Disconnect the battery first then remove that plastic cover and Serp belt. From there you will see some bolts holding it on and the cables in the rear. Remove those and thats it.

 

[dabuddha]

I'm looking at the following guides:

http://www.autozone.com/autozone/re...epairGuideContent.jsp?pageId=0900c152801e4746

and

http://www.autozone.com/autozone/re...epairGuideContent.jsp?pageId=0900c152801e4588

My belt needs replacing too since it's really wearing out. It all looks pretty "easy" but the only thing I can't figure out is how to loosen the tension on the belt. I see the picture in the diagram but my tensioner doesn't look like the one in the picture. Could I just use my hand and push down on it and then slip the belt off? Or maybe I could slip a long flat screwdriver to the top of the tensioner and pry the screwdriver counterclockwise

 

[LTC8K6]

I'm looking at the following guides:

http://www.autozone.com/autozone/re...epairGuideContent.jsp?pageId=0900c152801e4746

and

http://www.autozone.com/autozone/re...epairGuideContent.jsp?pageId=0900c152801e4588

My belt needs replacing too since it's really wearing out. It all looks pretty "easy" but the only thing I can't figure out is how to loosen the tension on the belt. I see the picture in the diagram but my tensioner doesn't look like the one in the picture. Could I just use my hand and push down on it and then slip the belt off? Or maybe I could slip a long flat screwdriver to the top of the tensioner and pry the screwdriver counterclockwise

There's usually a square hole in it that you can put a socket wrench in to move it and loosen the tension on the belt.

 

[dabuddha]

That's what it looked like in the guide. Could the square hole in my case be right on top of the pulley?

 

[LordMorpheus]

Your car has a belt tensioner, too, it's not quite in that same spot. (actually, I think it is in the same spot, but from a different angle)

The procedure is easy enough once you know what to do (took me a while to figure out how to get a wrench in the tensioner because my fan is so close to it - looks like you have an electric fan on your car so this should be easier), but you just get a 1/2" drive ratchet into the square socket on the tensioner arm and push it clockwise. Once you've done that, just slip the belt off the alternator pulley and let the tensioner back out - there will be enough slack at this point to take the belt off.

You'll need to be able to operate the tensioner to put the new belt on, anyway. To do this, go ahead and get the belt routed properly (there should be a diagram under you hood to make this clear) except for the alternator pulley. Just turn the tensioner again and slip the belt over the alternator pulley and let the tensioner out and you should be good to go.

Also, I have the ford service manual for Ford, Lincoln, and Mercury cars 96-99, so PM me your email and I'll send you a PDF of the alternator section for your car. Nothing surprising there, but it'll have the torque specifications for the bolts when you reinstall (autozone will loan you a torque wrench (and whatever other tools you need) for free, or at least they used to).

edit:

this is where you put your wrench:

 

[LTC8K6]

That's what it looked like in the guide. Could the square hole in my case be right on top of the pulley?

Looks like it. That's where it would normally be to give you leverage.

 

[dabuddha]

Thanks for all the info! Am planning on changing it this weekend (alternator + belt). A buddy of mine told me that it could be the automatic tensioner that's failing which could result in the belt slipping?

I see that the tensioner is only 48 bucks at autozone and it looks like it's held in place by 3 bolts only?

 

[Vette73]

Thanks for all the info! Am planning on changing it this weekend (alternator + belt). A buddy of mine told me that it could be the automatic tensioner that's failing which could result in the belt slipping?

I see that the tensioner is only 48 bucks at autozone and it looks like it's held in place by 3 bolts only?

If the Ten. was bad other items would also have issues. Like over heating, steering getting stiff, etc...

I would nto change until you take the belt off and see how tight it is. I doubt that has anything to do with your problem.

 

[dabuddha]

Ahhh good point. Haven't had any other problems except for the battery issue.

 

[dabuddha]

Ordered my alternator and a replacement belt. I'm as excited and giddy as a school girl!

 

[dabuddha]

Update:

Finally changed it out today. I've never done anything majorly mechanical (and this probably still doesn't count lol) but it only took me about 40 minutes. Had to get my wife's help when I was putting the belt back on cause I had to really push the automatic tensioner since the new belt wasn't as "stretched" out.

Before changing it, when I had the car on, the voltage was reading at 14.6 roughly. Then after turning everything on, it went back up to 14.6. I let it run for awhile and when the battery light came on, the voltage reading had dropped to 14.1.

With the new alternator, it's constantly reading between 14.1-14.2 right now. Haven't seen the battery light yet but fixin to go take it out for a ride.

/knock on wood.

 

[dabuddha]

Bump for new problem in OP

 

[SpatiallyAware]

Just running it for half an hour isn't enough to keep the battery charged... I'd take it for a good drive every 1-2 weeks, about an hour with some highway miles.

It sounds like just a dead battery..

 

[dabuddha]

Just running it for half an hour isn't enough to keep the battery charged... I'd take it for a good drive every 1-2 weeks, about an hour with some highway miles.

It sounds like just a dead battery..

I'll get the battery swapped out first. It's still under warranty at advance auto parts.

BTW even if the battery was dead, wouldn't having it hooked up via jumper cables still start it?

 

[LTC8K6]

I'll get the battery swapped out first. It's still under warranty at advance auto parts.

BTW even if the battery was dead, wouldn't having it hooked up via jumper cables still start it?

Sometimes you don't have a good enough connection for the jump to work well, especially if the battery is very low. Waiting 5 minutes is not long enough for a very low battery, either. Plus if your battery is bad, then you are relying entirely on current carried by the jumper cables.

At any rate, you now need a new battery anyway if it was that low.

So, I'd change the battery and see how it goes.

 

[manimal]

Always isolate your issue before throwing parts at it.

 

[SpatiallyAware]

I'll get the battery swapped out first. It's still under warranty at advance auto parts.

BTW even if the battery was dead, wouldn't having it hooked up via jumper cables still start it?

It should, but that car probably has a huge battery compared to the typically tiny toyota batteries. I've had a time or two where a smaller car, even when left for a good 5-10 min, still would not jump the larger vehicle.

The quick clicking is almost always battery. Starter might make one loud click and that's it, or a bit of grinding, but the 'click click click click click' is 99% of the time dead battery. I supposed it could technically be the starter solenoid clicking but starter motor bad, but that's rare.


Battery is the most likely cause, and it's the easiest to deal with.. So try the battery first, especially since it's under warranty.

You might want to invest in a float charger/tender if you can't drive it once a week or so..

 

[DaTT]

From my experience, clicks are always batteries.

Starters usually either do absolutely nothing, or just spin IIRC when pooched.