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Alternator Removal/Replacement How-To (2003 Astro)

81K views 81 replies 62 participants last post by  TOAD 
#1 ·
Replacement of an alternator is a general repair. In my case, this happened around 110K miles. There are ways to know you have a bad alternator before your van dies on the middle of the road. In my case, the battery light came on. A battery test revealed the battery was fine. That left another possible suspect--the alternator...uhg. Looking at the voltage output guage was a pretty good indicator too. The folks who tested the battery told me it should be indicating closer to 16/17, but in my case it was reading 14/15.

Now you may have a short somewhere. But some shops, like Advance, will test your alternator for free, so you're just out some time and sanity in pulling it out. Also maybe your battery just dies when parked overnight. That could be a voltage regulator. Unless I'm mistaken, GM put the voltage regulator in your alternator (different from Ford). A bad alternator may leave you needing a tow. Worse, a bad voltage regulator may also fry your battery, so don't waste time waiting for the nerve to get this done. There's no good reason for a backyard mechanic to fail on this, despite how daunting the job of accessing the alternator appears. No specialty tools are required. It just takes a little longer than on your sedan. To give an idea of what is meant here, this is a pic of the alternator:

It's between the air filter housing, the AC lines and just below the oil dipstick...no reason to be discouraged.

To begin, proceed as follows:

Edit (addition): This should have been number 1--safety first. Disconnect the battery. SWMBO made me do this, despite the fact that I like to listen to the radio as I work... The bolts on the side terminals of mine were 8 mm.

1. Remove the air intake as per this procedure:
http://www.astrosafari.com/viewtopic.php?f=9&t=1142

2. Remove the upper fan housing as per this procedure:
http://www.astrosafari.com/viewtopic.php?f=9&t=1143

3. To remove the belt from the alternator, slip a 3/8" extention into the belt tensioner, and pull up on the rachet. A good pic of the tensioner wasn't possible, but here's one showing the location with extension already inserted:


For more details on how to deal with that belt, refer to the removal procedure, here:
http://www.astrosafari.com/viewtopic.php?f=9&t=1144

4. Using a 13mm socket with extension(s) remove the two alternator bolts, located at the bottom of the alternator:


5. The alternator won't just lift right out. It needs coaxing with a pry bar and sturdy screwdriver, seen behind the coolant hose in this pic:


6. Don't just try to yank it out once you've unseated the part, because it's still attached via two wires.
6a. One is on the top, going in through a harness. Pull the clip out and pull the wire harness.
6b. The other is in the back of the alternator, covered by a slip on rubber boot. Slip the boot off and unbolt it (8 or 9 mm socket if memory serves me, but I may be wrong).

7. Now half the job is done. Pull out the alternator, maneuvering as needed, and taking care not to break the plastic fan. And this is what your left with:


Replacement is the exact reverse of this procedure. To seat the alternator properly, I recommend removing the transmission and oil dipsticks and coaxing with a long socket extension (or screwdriver) and mallet.
 
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#4 ·
Hi chemist
Great write up thanks. Just a side note for the older models like my 96, is the alternator with mine has a bracket at the back which bolts up to the rear of it as well as the ones you mentioned above, This is a 10MM bolt which is located in the upper left hand rear corner of the alternator when you face it. I can't see that bracket with your model year but I have on mine. Again thanks very much for the write up chemist, great work. :)
 
#6 ·
HI all.... Just replaced my Alternator.. did not take me long get it put in than getting old one out was bit stress!

here's some pictures I just take when put in new ALT in. sorry did not get any on old one coming out.









I did not have to take out the fan cover at all..

at first it was kind hard to get wires off the old ALT.. so go easy on it.

enjoy!

:layrubber:
 
#9 ·
i just did my alt on my 99 two weeks ago. There are only two bolts. The alt is kind of smushed in place. This post is identical to your 99. Once the bolts are loose pry on the side closest to the drivers side with a flat blade screw driver and it will slowly pop up. To put the new one in I had to tap on mine with a rubber mallet and a socket extension to squeeze it back into the mount. I found that this job takes about 30 min to line it all up and make sure you don't beat the heck out of it putting it in just tap it in. If you can move the front little spring clip things back as posted it would make life easier I just didn't see a way to move them when I did my alt.

Good luck.
 
#10 ·
I just replaced the Alternator on my 1994 Safari 4.3 L High Output engine option.

There is a third mounting bolt, found at the rear left of the alternator, approx 1/2 way down. It is a 10 mm bolt. Access to the bolt is limited at the rear, I ended up removing the engine cover so a friend could help from that side to get the bolt re-aligned and back in. Removing the engine cover also gave me more confidence about what I was doing at the rear of the alternator. I ended up moving the upper oil dipstick channel out of the way, to make it easier to use a 10 mm short socket and ratchet instead of a wrench to get the bolt back on. (Only move the upper oil dipstick channel if you have removed the engine cover, since the channel comes apart in the middle, and you will need access to re-insert the top of the oil dispstick channel into the bottom)

Another pointer, test the threads in your replacement alternator before trying to re-install. One of the threads on mine needed to get re-threaded for the bolt to actually screw into it.

I noticed some posts suggesting one should remove the belt tensioner inorder to get the alternator out. Certainly for my model and year Van, this was absolutely not required.

If your doing a 94 Safari, and need more confidence building info, email me, and I'll send you a detailed set of steps I followed, along with some supporting photos.

greg_gp1@hotmail.com
 
#11 ·
On my 97 the fan shroud is easy to remove and gives you a lot more room to work in there. Most of them are split (top/bottom) so you really only remove the top. There's two rubber pads that sit between the radiator edges and the shroud. Make sure you put those back when you put the shroud back on. I've removed it twice to replace the alternator and once to replace the tensioner. Piece of cake and the front of the engine magically appears once it's off.
 
#12 ·
currently have my cousins 96 astrovan followed all these instructions but mine too has a back bolt and I'm wondering how to get the damn thing out I don't have a 10mm wrench!!! socket fits but can't move the damn thing!!!! please help!!!!!!!!!!!!!!!!!!!!! :feedback:
 
#13 ·
just make sure you don't pull too hard forward on the alternator once its loose to remove the power cable, I did this and shredded the sensor cable that attaches to the backside of the alternator added an extra day of trouble shooting for doing that in the middle of January, not fun
 
#14 ·
Just replaced mine last weekend. Was not very hard at all, thanks to this post. only trouble was finessing the new alternator into place. Got a 160 amp unit that puts out 105 amps at idle from DB electric for around $180 shipped to me in 3 days.
 
#15 ·
Looks like I may be following these instructions soon. Since I bought my Van the amp gauge has been reading at or a touch below 14 volts, today on the way home it dropped to below what would be 12 volts with lights, wipers, defrost, & radio going. I was only a mile from home when I noticed, so I shut the lights, wipers, and blower down. The volts returned to about 12-13 volts. Not good.

Why do the Alternators have to be so pricey?
 
#16 ·
kidhauler said:
... If you can move the front little spring clip things back as posted it would make life easier I just didn't see a way to move them when I did my alt. .
In Duck Hunter's first pic, You can see how he moved them out forward. He inserted a bolt with a flat washer from the rear, then put a large, oversize spacer (looks like a lug nut) on the front side, then a flat & a nut. A few turns of the nut and they should be well out of the way.
 
#17 ·
one good piece of advice is for anybody who can go to a junkyard is to possibly pick up an alt off a 03 or 04 full size truck, the ad244 style puts out about 100 amps at idle, and up to 170 at full tilt. only diffrence is you hve to change out to a tad biit longer belt, either a 96 or 96.8
 
#18 ·
brilamb2 said:
one good piece of advice is for anybody who can go to a junkyard is to possibly pick up an alt off a 03 or 04 full size truck, the ad244 style puts out about 100 amps at idle, and up to 170 at full tilt. only diffrence is you hve to change out to a tad biit longer belt, either a 96 or 96.8
Great Info Bri... Thanks a lot. Jim
 
#20 ·
Gonna tackle this tonight on my 95 astro. Got the hook up from a friend at a parts store. 125 for a brand new 105amp Ultima. Lifetime warranty... we shall see how it holds ups.
I was driving to work this morning and the volt meter in the dash started jumping ariound and then went down to 12ish and the batt light came on and I could hear the nator saying EFFF YOOUU!! :screaming:

Welp, hope its just the nator... Hopefully it goes smooth....
 
#22 ·
Thanks for the great post and pictures, my son and I replaced the alternator,serpentine belt and belt tension pulley on his 97 Astro last week, all went well, we appreciate your help, I went over your steps several times before starting the job, would have taken a lot longer without it.

Thanks again.

Don
 
#23 ·
I see some slightly incorrect terminology here as well as in manufacturer's ads
when it comes to alternator output.

Alt's don't really "output 100 amps at idle". By themselves, they don't "output" amperage at any speed.
Amperage is a function of the load. The world's largest alternator, at any speed,
into a load that is "asking for" (drawing) ONE amp will output one amp, no more.

Better termininology would be "Is capable of supplying 100A at idle", rather than
"outputs 100A at idle".

A bigger alternator (amperage rating) may be beefier built than the smaller alt.
But unless you have added some kind of extra load to the electrical system, a bigger
alt will output the same current (amps) as the smaller one.

Alternators output 12 VOLTS (or 13.8 or 14.5 or whatever) constantly. They supply
AMPS to whatever extent the load requires.

E=IR

Lump
 
#25 ·
I have noticed on some forms you fill out, it asks you to print your name. Sorry I forgot my printing press. (I usually just letter my name in, instead)

How did we, speaking collectively, stray from using correct English. I sat in on an English class and the teacher used the word "can" instead of "may" in an instruction to the class for an answer. Everyone in the class could speak, the teacher was giving permission to the class to speak.

I'm sure there are many more examples of incorrect wording, but it shouldn't come from the English teacher.

Go figure...

Keith
 
#26 ·
94 Van Guy said:
I have noticed on some forms you fill out, it asks you to print your name. Sorry I forgot my printing press. (I usually just letter my name in, instead)

How did we, speaking collectively, stray from using correct English. I sat in on an English class and the teacher used the word "can" instead of "may" in an instruction to the class for an answer. Everyone in the class could speak, the teacher was giving permission to the class to speak.

I'm sure there are many more examples of incorrect wording, but it shouldn't come from the English teacher.

Go figure...

Keith
This "can" and "may" thing is a really insufferable bit of pedantry, commonly cited by people who don't understand actual issues of language mechanics. Also, I'm not fond of the doctrine of preventing language evolution - why don't you read some Chaucer and see just how much English has changed over the past few centuries?

Fyi, isn't the following sentence: How did we, speaking collectively, stray from using correct English. supposed to be a question? Whuh oh! and you follow it up with a triple preposition in the next sentence: "in an instruction to the class for an answer" Not my idea of elegance. Then, right after that: I'm sure there are many more examples of incorrect wording, but it shouldn't come from the English teacher. What's the antecedent of "it"? It's not supposed to be "incorrect wording", FYI. "They," referring to examples, would be correct.

To go back to an old cliche, those who live in glass internets shouldn't throw stones. C
 
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