Chevy Astro and GMC Safari Forum banner

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.
 
See less See more
5
#52 ·
awesome thread. did my swap today. took 45 min. would have been less but snapped the wire for the plug and also broke the pigtail for the one with the bolt. was able to ******* rig it back together with a conector/ extension wire for the plug and a new pig tail for the bolt one. this forum has saved me a ton already and ive only had my astro for 3 weeks. thanks a bunch
 
#53 ·
I've never seen this thread until now and I think I should point a few things out to anyone who is reading the main post!

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.
This is NOT true. Your alternator should NEVER be putting out more than 15.5volts unless you have it isolated from your stock wiring harness! Those voltages will fry all the electrical in your car!

Also maybe your battery just dies when parked overnight. That could be a voltage regulator.
The GM alternators (CS-130 and AD-244) are internally regulated meaning that the voltage regulator is inside the alternator. There are companies like Mechman or DC Power that can make those alternators with an external regulator though. Also, the voltage regulator has nothing to do with the battery draining at night! The voltage regulator doesn't draw power from the battery... it simply adjusts the DC current that the diodes output!

I don't have time to read more of the main post of the thread or the replies so I'm not sure what other information is wrong and if someone has already posted what I pointed out. Anyways, I hope people focus on the removal procedures rather than the other "content" that he posted.
 
#54 ·
The voltage regulator doesn't draw power from the battery...
A bad voltage regulator can cause the battery to discharge when the vehicle is off. A bad bridge rectifier can also cause the battery to discharge when the vehicle is off.

A bad regulator can also also cause the "battery" warning light to illuminate even though the system is operating normally.
 
#55 ·
astroid said:
Friday the light came on my '99 Astro and the gauge dropped to 10 amps. I drove a few miles to the Interstate battery shop, they tested the battery (which was just replaced a month ago) and told me to push the emergency brake down one click to shut my headlights off and drive straight home (another four miles). I replaced my alternator on Saturday. Beautiful day in the fifties but as usual with owning a vehicle that has half of its engine under the dash, the procedure was not pleasant.

Others have posted that the job was easy even without removing additional parts???? I removed the air cleaner, the metal tube directly behind the air cleaner, the fan shroud, a small hose that dripped antifreeze that went into maybe the heater core :shrug: . Only then did I have a chance to get the alternator into a position where I could get to the wiring on the rear. As I turned the nut, the nut below the pigtail also turned which snapped the pigtail (which I replaced). I then used a socket on the outer nut and a small needle-nosed vise-grip (a narrow wrench would have worked much better) on the inner nut while holding it down on the concrete driveway with my left foot.The replacement alternator slipped back in with a little nudging. The gauge is now up to 15 1/2 amps.

I had a choice of a brand x replacement for $80, a re-manufactured factory unit for $110(lifetime) and a new factory unit for $130(lifetime). I chose the middle unit. Did I make the right choice? :think:
I just had the same problem with my 99' as well. How many miles was on yours? I have a little over 80k on mine. BTW you might want to check your brake lines under your van as well. I seem to be having all kind of issues with my van. Mostly unchecked maintenance issues. But i forgot to check the brake lines when i bought the damn thing, so that's to be expected. I love to work on it though.

The alternator replacement is not fun. So i feel your pain. But I did not disconnect any fluid hoses to do it though. The two that are above the alternator moved easily enough where i could manipulate the alternator to get to the wiring in the back once i got it loose. The one thing i did do was forget to put that rubber cover back over the double stud bolt after i had installed the refurbed alternator. I realized how hard it was, so i made a Youtube video in three parts on how to replace the dam thing. It was my first video i ever uploaded and is kinda long winded, but i made so others won't make the mistakes i did. If you want the link let me know. BTW I am doing one on replacing my brake lines, so that's gonna be fun. GL TU
 
#56 ·
JayDubya said:
I've had bad luck with re-manufactured units twice. Bad bearings shortly after installation. They must pound them in with a hammer. Now I only buy new.
I did buy a refurbed, but like you said the bearings can be a problem. I always spin them in the store before i buy them and see how it compares to the new. The refurb one i bought had a little bit tighter spin than the new one, but not bad enough that i did not buy it. Been working like a charm, but If you do go refurb, i would at least compare it to the new one first. It it makes a kind of scraping noise or has a real tight pulley on it do not buy it.
 
#57 ·
mobile said:
1998, I have the housing out of the way, belt off, and 2 bolts out. It won't budge. I will try prying. You guys sure the 98 does not have a 3rd bolt??
The alternator has two sleeves in the bolt holes for making it snug. If you have the belt off, and bolts off, just pry gently up on one side underneath of it, and then tap the end of what your using to pry with. It will come out. When you put the new one on, you can use a rubber mallet to tap it in. I used an old wood chisel and tapped it gently down on a thick side of the housing. Still workin. I know this is an old post, but hopefully it will help someone.
 
#60 ·
Great write-up! Was tons of help when I changed out the stock alt. for a AD244 version.

One tip I'd like to add, watch out for the main vacuum line going across the top of the engine to the passenger side. I broke mine taking the alternator out. That will result in the defrost vents only condition.
 
#62 ·
Great write up here and helpful added comments. I just did an alt replacement. I have been watching and listening to my alt for a year. On a trip it just quit, $150 for extra miles after my towing coverage :banghead:
I decided to go with the truck alt that's 145 amp and am happy. I did use a used one so if it didn't work out , I wouldn't be out so much money. Also did the Big 3. I added a ground to the alt bracket behind the left mounting bolt to the frame with a frame to body ground. Origonal battery ground to engine is at least 4ga and I had added a body ground years ago with my first amp. Next I will replace the wire from battery to the underhood fuse box and will look at new wire to the blower. I do see alot of small ground wires near headlights that just look too small. :confused:
Test ride last night..... NO, my headlights do not seem brighter. BUT, a solid 14.4 ? on the gauge, driving, at idle, with nothing on, with everything on!!!! Awesome! One problem..... my rear heater fan is rather obnoxious now at full speed. I guess full speed is a bit faster now.
The BEST HELPFUL INFO on this thread was to use a bolt to withdraw the metal sleeves before installing the new alt!
My helpful hint is USE DIELECTRIC GREASE on EVERY CONNECTION, BOLT. I used it last time I did plugs,wires,cap,rotor,coil and 3 years later my coil, wires are good to go still!!!
I do see a lot of brittle insulation on many different wires due to engine heat. The small alt wire needed a fix.... slit open a flexible hose, filled it with silicone and zip tied it over the wire.

One note on the upgraded alt, it is tight to the cruise/throttle cables bracket and with a new 4ga wire from alt to battery, it needs to be placed in an exact spot(the 4ga wire).

I used to have trouble if I idled a while with both heaters or ac units running. volts dropped a lot. This upgrade fixed that.

Question...... what size fuse to install in the line from the battery to the alternator? I am guessing I need a 150 amp fuse as the alt is 145amp. And I need new battery connector bolts for all these extra cables. I have top and side posts but I would like to clean it up for using just side posts. ANyone have a nice set up for this?
 
#63 ·
I had to replace the alternator this past weekend on my 2001 Safari. I guess the original alt wanted a rest after 251,000+ miles. Thanks to the easy to follow "how-to" by Chemist and the spring clip tip from Duck Hunter, the job was fairly simple and straightforward. New belt, tensioner pulley and idler pulley while I was in there. This board is an invaluable resource to keep our vans rolling along!
 
#64 ·
Older topic, but still need to give a major thanks. After reading some people complain about it being a PITA, I found it pretty easy, but MUCH easier after reading this post. The tip about using the bolt to push the spring pins out made dropping the alternator in cake walk, otherwise trying to muscle it in would have been a booger. Also so worth the five minutes to remove the upper radiator fan shroud :thumbup: way easier to access the front of the engine. Don't know how hard it is for you guys with the third bolt, but for us guys with the two bolts, it is easy peasy :banana:

thanks for making this job low stress!
 
#65 ·
Just took my 98 Safari into MIDAS for a wheel alignment.

Strange coincidence, but the next day I heard a NEW sound coming out from under the hood.
Sort of a Humming/whirring noise, similar to a supercharger spooling up, that increased with RPM.
HMmmmmm??

Thought it might be power steering pump low on fluid or possibly the alternator.

Sure enough, next morning after a 200 km road trip, with both headlights and A/C on high, my van would not start.
Dead battery.
Did not notice any lights left on so ....?

Charged the battery overnight, and it came up to 13 V.
Checked the charging output at idle with a multi meter and it is at 14.2 V.
Dash gage shows 13.9 V.

So now both the battery and the alternator seem OK??

Looked up the repair receipts and the alternator is a replacement BOSCH, 10 yrs old, with 130 Km on it.

Hopefully it is not time to do a re and re on the alternator.
If I do have to do a replacement, glad to find the detailed instructions in the thread here on the site.
 
#67 ·
Midas checked both the alternator and the battery.
Battery tested out as good, alternator NOT good. Only putting out 12V.
They say it is probably a blown diode.

I have A SPARE PARTS VAN with low Kms on it so will pull the alternator tomorrow and replace it.
OH BOY!!
 
#68 ·
LAZ 1 said:
Midas checked both the alternator and the battery.
Battery tested out as good, alternator NOT good. Only putting out 12V.
They say it is probably a blown diode.

I have A SPARE PARTS VAN with low Kms on it so will pull the alternator tomorrow and replace it.
OH BOY!!
Way to go. Check the simple stuff. Should ALWAYS be the first step.

When Midas checked the alterntor, did they remove it from the van or something else?

Lump
 
#69 ·
LAZ 1 said:
Checked the charging output at idle with a multi meter and it is at 14.2 V.
Interesting how it was working when you tested it, but failed under their test.
 
#70 ·
Interesting that it failed the day after the van went in to Midas for a wheel alignment ...
coincidence??

In any case, I swapped in another alternator from my spare parts van. Voltage now reads 14.5V at idle no load. Under full load, wipers, lights, fan, still reads 14.2V.

Old alternator did read 14.2V at idle, but under load dropped to 12V or less. So it appears I DID have a bad alternator. Plus the odd noise from under the hood is now gone.

THANKS for the advice on pulling the sleeves out a bit. Made it much easier. Two hours to remove two alternators and reinstall one used alternator. Midas quoted me close to $400 parts and labor with a REMAN alternator. Quite a saving for a couple hours work. And the rain held off until just after I finished.
BONUS!!
 
#74 ·
Thanks for the tutorial! Gave me an edge when replacing the alternator in our 97 Safari today.

Definitely easier with the extra steps of removing the air cleaner and upper fan shroud first. I also replaced the pulley on the tensioner since it seemed just a little wobbly, but the new one felt the same so maybe it was OK after all. Oh well, cheap insurance.

Only difficult part was the passenger's side bolt was corroded and fought me the entire way out - took about 45 minutes just to remove it! Probably could have zipped it out with an impact, but I was a-scared of messing up the threads so took my time.

I did find that a 6 point 1/2" socket worked well. Began with the 13 mm as suggested but since I had to pull so hard on the passenger's side bolt the 13mm 12 point seemed to indicate it wanted to slip.

Now producing 14.5 volts at idle, no load; 14 v at idle with lights and fans on. Was 13.5 and <12 :(

Thanks again!
 

Attachments

#75 ·
I want to thank chemist for this excellent article. I had assumed I would have to do a lot more disassembly, but the replacement went smoothly following his method. I would add one additional bit of information. I see another reader mentioned sleeves in the alternator mounting ears. In my case (a 2005 with CS alternator) the casting that carries the alternator has them in the front mounting holes. They are split steel sleeves that can slide in the casting to accommodate manufacturing dimensional differences in the alternator mounting ears. When the mounting bolts are tightened down, they are actually sliding the tolerance sleeves against the alternator mounting ears. They are tight when you remove the alternator, which accounts for the usual need to pry it out. You shouldn't have to force it back in, however. The photo below shows how to press the sleeve forward, giving clearance for the alternator. I used a 3/8 inch grade 5 bolt and hardened washer, with (I think) a 14 mm socket to clear the spacer. You only need to tighten the bolt/nut a turn to achieve generous clearance, so the alternator drops back in easily. Hope this is helpful.
100_1551.JPG
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top