Alternator, belt or Water in gas problem?

Tiny
DABOSSS
  • MEMBER
  • 2004 CADILLAC DEVILLE
  • 4.6L
  • V8
  • 2WD
  • AUTOMATIC
  • 106,600 MILES
On 9/22/2014 As I was headed to work, I stopped at a local Gas station and filled my 04 Deville up, drove into work with no problems. That night as I was leaving work I sat in my car outside letting it warm up as I normally do, after about 5 minutes of it running it suddenly died, the voltage dropped to 11, 2 volts, I was able to restart it, and took off, I got about 2 miles down the road when it died again showing a voltage drop. ( There were never any warnings of the system not charging or a battery light coming on other than the battery light coming on as the car had already stalled out ) I drove 20 miles home and never had one problem out of it, I was able to stop at traffic lights and it remained at a constant 14.5 volts, never dying. As soon as I got into my driveway and got out to open the garage door, the car died again, showing yet another voltage drop back down to 11, 2 volts.

I got up the next morning and went to work with no problems, no stalling out, no hesitation, no nothing. As I left work last night for my two days off, it ran fine. This morning as I got up to go have a load put on the battery ( which is one of those red top battery's ) it crapped out again, and died before I ever got the car out of the garage. Again showing a voltage drop of 11.2 volts, again no warnings about the system not charging, but this time it was different, there was hesitation and sputtering in the motor as I tried to idle it up. I took it to a local auto parts store and had them load test the battery, it came back to being at 14.6 volts under a load, and 12.7 volts with the car not running. I then had them do a load test for what its worth on the alternator as the car was running, and it came back as the alternator passed.

My question is, could it be the voltage regulator in the alternator going bad, or the alternator as a whole taking a slow crap on me? Or could it just be that there is water in my gas tank that's causing the car to crap out? Or could it be the belt? The belt looks fine, it don't ( to me at least ) seem as tight as it should be, but I'm a big guy and I tend to like everything over tightened.

I don't wanna go buy a new one and tear the car apart only to find out that it was not the problem. I know electrical issues can be tricky to solve, more so just by way of telling someone the symptoms I am experiencing with the car, but I just do not see it as justifiable to tear the car apart yet until I have a general Idea of what the problem really is.

these are all the symptoms I have experienced in the past two days, and it didn't start until I filled my gas tank up.
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Wednesday, September 24th, 2014 AT 10:59 AM

9 Replies

Tiny
DABOSSS
  • MEMBER
As a side note, and I am not sure if this matters, but the mileage on the car is 106,000.
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Wednesday, September 24th, 2014 AT 11:03 AM
Tiny
HMAC300
  • EXPERT
Replace belt and tensioner 60k is recommended unless in California then 105k make sure battery terminal ends are clean see if that helps it may solve it
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Wednesday, September 24th, 2014 AT 12:35 PM
Tiny
DABOSSS
  • MEMBER
I will be checking them momentarily, and inform you of any findings.
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Wednesday, September 24th, 2014 AT 12:39 PM
Tiny
DABOSSS
  • MEMBER
Ok so what I looked at were the battery terminals were clean and free of corrosion, the tensioner was tight and no play in it, however the belt looks worn, but there were no visible signs of cracks or dry rotting. I know that doesn't mean anything cause heat from an engine compartment will break down all sources of rubber, but it visually had no cracks or anything to it.
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Wednesday, September 24th, 2014 AT 1:01 PM
Tiny
HMAC300
  • EXPERT
It may not show any cracks if it looks worn replace both tensioner and belt. There is a special tool that you use to measure it if it's worn and with that many miles it probably needs it.
Tensioners lose tension over time and even though it seems tight when running it may not be and it's a good place to start anyhow. If you are concerned about belt diagrams they are on site here just go to repair diagrams.
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Wednesday, September 24th, 2014 AT 1:37 PM
Tiny
DABOSSS
  • MEMBER
Thanks. In your personal opinion, does it sound like its the belt and tensioner, alternator, or maybe the water in the gas tank?

I put a can of Heet in with the fuel to hopefully help with the issue of possible water, and as I started the car up a little bit ago, it ran fine. No signs of stalling out.

I know this past winter I had somewhat of the same issue, I chalked it up as a temperamental car that does not react well in the Cold Ohio winter. Now I am second guessing that and wondering if it was the same issue I am experiencing now.
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Wednesday, September 24th, 2014 AT 1:40 PM
Tiny
HMAC300
  • EXPERT
I kind of doubt the water in tank thing as alcohol is already mixed in your fuel anyhow besides fuel injection has pretty much eliminated the carb icing that water would cause Of course if you use the cheap gas like Mikes really cheap stuff then it may. But it really thingk it the belt and tensioner.
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Wednesday, September 24th, 2014 AT 3:02 PM
Tiny
DABOSSS
  • MEMBER
I'll trust you on this one, as you were dead on the money with my wiring issue in the truck when I was having tail light/ license plate back up lamp issues.
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Wednesday, September 24th, 2014 AT 3:06 PM
Tiny
DABOSSS
  • MEMBER
Trunk* not truck
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Wednesday, September 24th, 2014 AT 3:07 PM

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