Alternator Removal/Replacement (2003 Astro)

[chemist]

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:
viewtopic.php?f=39&t=2699

2. Remove the upper fan housing as per this procedure:
viewtopic.php?f=39&t=2700

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:
viewtopic.php?f=39&t=2701

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.

[dunedog]

Also, once the alt is out ,knock back the little spring tube clips where each bolt goes thru.
This makes it ALOT easier to get the new alt back in place. oh,again ......... having a lifted van makes the job easier
side note : alt putting out 14-15 amps would seem normal to me ?

[Spike99]

Thanks for your write up and online pictures chemist. Much appreciated.

Ya. My previous '95 Safari RWD van went through 1 x alternator as well. Seems the lack of "under the hood" air space / air flow tends to over cook a high number of Safari / Astro alternators (especially around the 100K mile mark). Due to being "on vacation with my family", I couldn't do the alternator replacement work myself. Thus, an auto shop had the pleasure of making lots of easy replacement dollars from me. GGGRRRR.... If my van was local, I would have replaced the bad alternator myself - using your online instructions.

thanks for showing us how easy `swapping out alternators` can be.

.

[cengster]

99 Astro dont have to take fan shroud off. Turn the alternator backwords and upside down it will come out!

[Rileysowner]

Be careful with the pry bar, I succeeded in breaking the mount where the bolt goes through closest to the passenger side. I hate forged aluminum. I know it is light, but it is so brittle. Oh well. hopefully I can get a new mount from a wrecker so I can get the new alternator in.

[Rileysowner]

Having broken the one mount I am wondering for future reference how I can avoid that. What can I do to in the future to avoid this happening. Where and how should I pry the alternator out. With that, how do you get the new on in? I wouldn't want to break the mount I am getting from the wrecker while installing the new one.