My 2000 Sienna makes an intermittent noise which intensify with
throttle. It sounds exactly like the sound of a regular hand held power
drill. My usual mechanic said it is most likely the alternator when I
asked whether it is the water pump. (We could not reproduce the noise
when I brought the car in).

He said not to worry about it since I can still drive some distance if
the alternator fail. (Is it true ?) He suggested I bring the car in
when the noise gets louder.

I am thinking of either rebuilding the alternator myself or buy a
rebuild or new unit and change it myself. Is the part easy to change in
the van ?

Thanks for sharing your knowledge.

J

"Jack" <buywheels (AT) hotmail (DOT) com> wrote

Whining noises that match engine speed are usually associated with the
alternator or power steering pump. Water pumps tend to leak before they
make a lot of noise.

I do not know if rebuild kits are available for your alternator, and you
will need pullers in order to change the bearings. If you decide to install
a remanufactured alternator, I recommend getting one from a Toyota dealer.
The remanufactured alternators sold by Toyota dealers are 100% tested so
they are pretty good quality. I've heard stories of bad remanufactured
alternators from auto parts stores, requiring several exchanges before
getting a good one. While you're at it, it would be worthwhile to change
the drive belt if you have more than 60,000 miles on it.

Changing an alternator should not be difficult if you have a basic metric
socket set and a pry bar.
--
Ray O
correct the return address punctuation to reply

Every older Sienna I've ever worked on has a high-pitched whine coming from
the alternator. In the begining we tried replacing and rebuilding units,
but the noise always persisted. Eventually all the owners gave up and got
used to it as there never really has been a problem beyond the noise.

qslim, 10/24/2005, 7:07:30 AM,
<309d70a82341136ec5b3f0de32b0ad94 (AT) localhost (DOT) talkaboutautos.com> wrote:

That's what the Ford dealer told me when I kept taking my 97 F-150 in
for the constant rattling from every orifice it had. "This is not a
Toyota, this is a Ford. Get used to the rattling."

--
"Golf is the hardest game in the world to play, and the easiest to
cheat at." -- Dave Hill

"Every older Sienna I've ever worked on has a high-pitched whine coming
from
the alternator. "

May I ask if the noise you were referring to a kind of constant
"background" noise ? The noise in my van comes and goes, and when it
appears it gets louder if I rev up the engine.

"Changing an alternator should not be difficult if you have a basic
metric
socket set and a pry bar. "

Can you tell me how do I set the belt tension ? There seems to be two
bolts holding the alternator in place, and a third bolt use for
adjusting. Do I use the third bolt for adjusting belt tension ? And how
do I know how tight is tight enough ?

Thanks again for sharing your knowledge.

"Jack" <buywheels (AT) hotmail (DOT) com> wrote

qslm can give much better advice there. If there are 3 bolts, most likely,
1 bolt serves as a pivot, another serves to adjust, and the last one locks
and holds the adjustment.

The proper way to check belt tension is with a belt tension gauge. The
factory manual will have specifications for a new and used belt. The
seat-of the pants way is to push down on the belt between pulleys and see
how much it deflects. On an older belt, an inch to an inch and a half is
OK. If the belt is slipping, you will probably hear it squeal/screech. If
it is not squealing/screeching, then it is probably tight enough.

Be aware that it is possible to have a belt that is too tight. If the belt
is too tight, over time, it may ruin the bearings on the accessories being
driven, like the power steering pump, alternator, and AC compressor.
--
Ray O
correct the return address punctuation to reply

"Ray O" <rokigawa (AT) tristarassociatesDOT (DOT) com> wrote

Deflection has no meaning unless you specify the length of that section of
belt and/or a pressure to apply. A longer run will deflect much more than a
shorter length and the more pressure you apply, the more deflection you'll
get.

-Bruce

"Bruce Chang" <bechang (AT) swspambegonebell (DOT) net> wrote

--
Ray O
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