alternator hot, engine off

[Wes]

2006 Ranger, 3.0L

The alternator was getting hot with the engine shut off (eventually ran
the battery down to zero). Since I suspected it was causing an annoying
squeak anyway, I bought and installed a new alternator. Imagine my
surprise when after I hooked it up I noticed it starting to get hot just
like the old one (engine off). After I disconnected the battery, I
checked a few of the wires with a multi-meter. I discovered that the
heavy black/red wire bolted to the alternator was showing a full ground
(even after disconnecting it from the unit). I also noticed that I would
only get a partial ground if I disconnected the 3-prong plug from the
alternator.

Mostly just to see what would happen, I reconnected everything and fired
the truck up. It sounded great and there were no indications of a
problem from the vast array of idiot lights (or light). However, when I
touched the casing of the alternator after 30 seconds of running, I
almost left some skin behind it was so hot. I immediatly shut it down
and disconnected and removed the battery. I'm starting to suspect that I
just replaced an old bad alternator with a new bad alternator.

Any thoughts?

[Wes]

Post by Wes
2006 Ranger, 3.0L
The alternator was getting hot with the engine shut off (eventually ran
the battery down to zero). Since I suspected it was causing an annoying
squeak anyway, I bought and installed a new alternator. Imagine my
surprise when after I hooked it up I noticed it starting to get hot just
like the old one (engine off). After I disconnected the battery, I
checked a few of the wires with a multi-meter. I discovered that the
heavy black/red wire bolted to the alternator was showing a full ground
(even after disconnecting it from the unit). I also noticed that I would
only get a partial ground if I disconnected the 3-prong plug from the
alternator.
Mostly just to see what would happen, I reconnected everything and fired
the truck up. It sounded great and there were no indications of a
problem from the vast array of idiot lights (or light). However, when I
touched the casing of the alternator after 30 seconds of running, I
almost left some skin behind it was so hot. I immediatly shut it down
and disconnected and removed the battery. I'm starting to suspect that I
just replaced an old bad alternator with a new bad alternator.
Any thoughts?

UPDATE.

So I gave in to the inevitable and took the suspect replacement
alternator back and and picked up another one. Yup, that was the
problem. Who'da thought that the one right off the shelf would have the
exact same problem as the original.

Oh well, at least it's all fixed now.

On an interesting side note, before I gave up on the first replacement,
I ran through a few troubleshooting tests. As such, I had re-connected
the battery and started the engine for the operating portion of the
tests. When I saw trouble lights indicating problems with the charging
circuit, ECM and even the ABS system, I don't have to tell you that I
got a sick feeling in my gut (it was right about then that I shut it all
down and yanked the alternator again). Fortunately, everything was back
to A-OK with the installation of the new (new) alternator.

[Dick Cheney]

Post by Wes
2006 Ranger, 3.0L
The alternator was getting hot with the engine shut off (eventually ran
the battery down to zero). Since I suspected it was causing an annoying
squeak anyway, I bought and installed a new alternator. Imagine my
surprise when after I hooked it up I noticed it starting to get hot just
like the old one (engine off). After I disconnected the battery, I checked
a few of the wires with a multi-meter. I discovered that the heavy
black/red wire bolted to the alternator was showing a full ground (even
after disconnecting it from the unit). I also noticed that I would only
get a partial ground if I disconnected the 3-prong plug from the
alternator.

What was the brand of rebuilt you got? Just curious, I suspect most
of them are only as good as the one year warranty they come with.

[Wes]

Post by Dick Cheney

Post by Wes
2006 Ranger, 3.0L
The alternator was getting hot with the engine shut off (eventually ran
the battery down to zero). Since I suspected it was causing an annoying
squeak anyway, I bought and installed a new alternator. Imagine my
surprise when after I hooked it up I noticed it starting to get hot just
like the old one (engine off). After I disconnected the battery, I checked
a few of the wires with a multi-meter. I discovered that the heavy
black/red wire bolted to the alternator was showing a full ground (even
after disconnecting it from the unit). I also noticed that I would only
get a partial ground if I disconnected the 3-prong plug from the
alternator.

What was the brand of rebuilt you got? Just curious, I suspect most
of them are only as good as the one year warranty they come with.

I got them both from NAPA. Ironically, the first one (the dead on
arrival one) was their "premium", life-time warranty re-man. I don't
recall a particular brand name on it - a few Asian symbols. When I took
it back, they didn't have any premium types in stock, so I took their
"lesser", 3-year warranty re-man and a refund in the price difference.
This second one - the one that worked - was actually an OEM Motorcraft.

I wonder if there is a lesson there...?

W.

[SMITH29]

Post by Wes

Post by Dick Cheney

Post by Wes
2006 Ranger, 3.0L
The alternator was getting hot with the engine shut off (eventually ran
the battery down to zero). Since I suspected it was causing an annoying
squeak anyway, I bought and installed a new alternator. Imagine my
surprise when after I hooked it up I noticed it starting to get hot just
like the old one (engine off). After I disconnected the battery, I checked
a few of the wires with a multi-meter. I discovered that the heavy
black/red wire bolted to the alternator was showing a full ground (even
after disconnecting it from the unit). I also noticed that I would only
get a partial ground if I disconnected the 3-prong plug from the
alternator.

What was the brand of rebuilt you got? Just curious, I suspect most
of them are only as good as the one year warranty they come with.

I got them both from NAPA. Ironically, the first one (the dead on
arrival one) was their "premium", life-time warranty re-man. I don't
recall a particular brand name on it - a few Asian symbols. When I took
it back, they didn't have any premium types in stock, so I took their
"lesser", 3-year warranty re-man and a refund in the price difference.
This second one - the one that worked - was actually an OEM Motorcraft.
I wonder if there is a lesson there...?
W.

xxxx
I have over the years bought a lot of parts from NAPA but had to quit
using them.
If you don't have your reciept for a return to another store or even the
one you bought the item from you may well not get any consideration.
After getting screwed that way I found out the stores are franchises and
no internet customer file to look you up.
I use O'Reilly auto parts now and their records cover Shucks customer
history as well.
Never an argument about returns anywhere in the country and they know
every part you buy by bringing your file up on the system.
They have quality parts as well and the choice of how much you want to
spend and lifetime is available too and you don't need no steenking
paperwork.
http://www.oreillyauto.com/site/c/home.oap

--

[charlie]

Post by SMITH29

Post by Wes

Post by Wes
2006 Ranger, 3.0L
The alternator was getting hot with the engine shut off (eventually ran
the battery down to zero). Since I suspected it was causing an annoying
squeak anyway, I bought and installed a new alternator. Imagine my
surprise when after I hooked it up I noticed it starting to get hot just
like the old one (engine off). After I disconnected the battery, I checked
a few of the wires with a multi-meter. I discovered that the heavy
black/red wire bolted to the alternator was showing a full ground (even
after disconnecting it from the unit). I also noticed that I would only
get a partial ground if I disconnected the 3-prong plug from the
alternator.

What was the brand of rebuilt you got? Just curious, I suspect most
of them are only as good as the one year warranty they come with.

I got them both from NAPA. Ironically, the first one (the dead on
arrival one) was their "premium", life-time warranty re-man. I don't
recall a particular brand name on it - a few Asian symbols. When I
took it back, they didn't have any premium types in stock, so I took
their "lesser", 3-year warranty re-man and a refund in the price
difference. This second one - the one that worked - was actually an
OEM Motorcraft.
I wonder if there is a lesson there...?
W.

xxxx
I have over the years bought a lot of parts from NAPA but had to quit
using them.
If you don't have your reciept for a return to another store or even the
one you bought the item from you may well not get any consideration.
After getting screwed that way I found out the stores are franchises and
no internet customer file to look you up.
I use O'Reilly auto parts now and their records cover Shucks customer
history as well.
Never an argument about returns anywhere in the country and they know
every part you buy by bringing your file up on the system.
They have quality parts as well and the choice of how much you want to
spend and lifetime is available too and you don't need no steenking
paperwork.
http://www.oreillyauto.com/site/c/home.oap

As an O' Reilly stock holder, I thank you profusely.