While I'm in there...Replacing Alternator.

steamcorners

Original poster
Member
Apr 4, 2012
13
New guy here.

I've got to replace the alternator this weekend in my wife's 06 Trailblazer LS, I6, 4wd. I've done a bit of other work on this truck myself, including the fan clutch last year. The alt functions fine, but the bearings are going bad, audibly.

I'm curious, what should I be doing while I'm in there? In other words, what will I be doing in about six months that will require removal of the alternator?
 

MacMan

Member
Mar 3, 2012
194
Replace the thermostat with a new AC Delco unit. If it goes bad, you have to move the alternator to get to it. Maybe a new temp. sensor too.
 

Voymom

Member
Feb 3, 2012
2,523
If you do the T-stat you might as well do the water pump, which has been known to fail after changing the T-stat, it may not require removal of the alternator but you might as well kill 2 birds with 1 stone instead of having to replace it 6 months down the road. Just my 2 cents!
 

steamcorners

Original poster
Member
Apr 4, 2012
13
I forgot, I did the water pump last year at the same time as the fan clutch.

How much time should I budget for this job? I'm a reasonably competent shadetree mechanic. I have a single day without the kids (Good Friday) that I can do a bunch of neglected maintenance to my fleet, and I want to get some work done on the Miata....
 

Voymom

Member
Feb 3, 2012
2,523
steamcorners said:
I forgot, I did the water pump last year at the same time as the fan clutch.

How much time should I budget for this job? I'm a reasonably competent shadetree mechanic. I have a single day without the kids (Good Friday) that I can do a bunch of neglected maintenance to my fleet, and I want to get some work done on the Miata....

Okay, then minus the water pump lol. The t-stat took my husband and I a little over an hour to do, but we took beer breaks in between :biggrin: The sensor? Well we havent done that yet to my voy, but I heard its not to bad.

BTW-Welcome aboard!
 

steamcorners

Original poster
Member
Apr 4, 2012
13
Voymom said:
BTW-Welcome aboard!

Thanks. I lurked a bit at the place that shall not be mentioned, but posted very infrequently.

I'll admit I'm not the truck enthusiast many here are. I prefer my automobiles small and quick: I've got an old Miata in the garage, as well as a mid-80's Honda Civic road-race car. The Trailblazer is my wife's daily driver, and tow vehicle once the race car is ready for the track.
 

MAY03LT

Member
Nov 18, 2011
3,412
Delmarva
steamcorners said:
How much time should I budget for this job?

First time folks have reported up to 4 hours for the alt/t-stat. That also includes the trip to the store to get a ratcheting 15mm wrench for the bottom alt bolt. I average 2 hours but I don't rush.

Also, not to second guess your diagnosis, but did you check the idler pulley that sits near the alt? The only reason I ask is, I've done a lot of alt replacements but only replaced one for bearing failure. I've replaced over 9000 idler pulleys for noise.

steamcorners said:
I lurked a bit at the place that shall not be mentioned

Say it once, say it twice, third times the charm...trailvoy, trailvoy, trailvoy!!!:wootwoot:
 

steamcorners

Original poster
Member
Apr 4, 2012
13
MAY03LT said:
First time folks have reported up to 4 hours for the alt/t-stat. That also includes the trip to the store to get a ratcheting 15mm wrench for the bottom alt bolt. I average 2 hours but I don't rush.

Also, not to second guess your diagnosis, but did you check the idler pulley that sits near the alt? The only reason I ask is, I've done a lot of alt replacements but only replaced one for bearing failure. I've replaced over 9000 idler pulleys for noise.

I'm 99% certain that it's the alt. I stuck a stethoscope against the bearing, and heard the noise...
 

MAY03LT

Member
Nov 18, 2011
3,412
Delmarva
steamcorners said:
I'm 99% certain that it's the alt. I stuck a stethoscope against the bearing, and heard the noise...

Did you spin it by hand or was the engine turning it?
 

MAY03LT

Member
Nov 18, 2011
3,412
Delmarva
Well done! Good luck with the project.:cool:
 

Wyle

Member
Dec 4, 2011
200
steamcorners said:
Thanks. I lurked a bit at the place that shall not be mentioned, but posted very infrequently.

Incorrect. Feel free to mention TrailVoy all day long here. Just don't mention GMTNation over there or type it for that matter. You'll either get nasty notes from the Admin/mods (when they stop by), be exiled ("no longer with us"), or be very confused when "GMTNation.com" literally becomes "TrailVoy.com" when you hit enter.

On the really amusing side, no one can ever claim there are "jerks that run GMTNation.com" :rotfl:
 

steamcorners

Original poster
Member
Apr 4, 2012
13
Wyle said:
Incorrect. Feel free to mention TrailVoy all day long here. Just don't mention GMTNation over there or type it for that matter. You'll either get nasty notes from the Admin/mods (when they stop by), be exiled ("no longer with us"), or be very confused when "GMTNation.com" literally becomes "TrailVoy.com" when you hit enter.

On the really amusing side, no one can ever claim there are "jerks that run GMTNation.com" :rotfl:

LOL. I come from a racing forum that split away in a similar manner from a larger, corporately-owned site. Six years later, feelings are still sore. Thus I try not to poke the bear.
 

Mark20

Member
Dec 6, 2011
1,630
Did a lot reading when I had to do the t-stat so I was prepared for the alternator. The first time it took about 45 minutes. I had to pull it again a week later and that took about 20 minutes. Once you know what you need to do its not a hard job.
 

gmcman

Member
Dec 12, 2011
4,656
MAY03LT said:
. That also includes the trip to the store to get a ratcheting 15mm wrench for the bottom alt bolt.

Absolutely.

The one with the reversible switch comes in handy if you back the bolt all the way to the A/C line. Don't back the bolt out to the A/C line unless you have the reversible wrench...just sayin, or you need to lower the A/C compressor to get it off, the stubby 15mm is ideal.
 

Mark20

Member
Dec 6, 2011
1,630
15mm stubby flex head ratcheting wrench. Surprisingly expensive at Sears (~$25) but is made the lower bolt easy. Used a full size wrench for the leverage to break the bolt loose and tighten but the flex head to get it out and in.
 

Sparky

Member
Dec 4, 2011
12,927
I replaced my alternator in a little over an hour IIRC. I had the same issue as you, it worked OK but the bearings made a racket.

I didn't use a ratcheting wrench for the bottom alt bolt, I think I just used a few different extentions and maybe a swivel with my ratchet for everything.
 

steamcorners

Original poster
Member
Apr 4, 2012
13
Argh. My stubby flex ratcheting wrench is too thick/wide to fully engage the bottom bolt on the alt. Off to Sears.

Also, the idler pulley IS bad, too. The alt bearings are definitely going bad, but the idler is even worse. Off to Advzonpa.
 

steamcorners

Original poster
Member
Apr 4, 2012
13
DONE!

Alternator, t-stat, sensor, and plugs replaced. Throttle body cleaned. Fired up pretty quickly--took an extra second or two of cranking, but running beautifully now.

Thanks everyone--especially MAY03LT, your Youtube vids helped tremendously.
 

davenay67

Member
Jan 16, 2012
217
steamcorners said:
DONE!

Alternator, t-stat, sensor, and plugs replaced. Throttle body cleaned. Fired up pretty quickly--took an extra second or two of cranking, but running beautifully now.

Thanks everyone--especially MAY03LT, your Youtube vids helped tremendously.

Excellent, glad to hear it went well. I did roughly the same job a couple of months ago (removed alternator to get at T-stat and CTS) and I spent more time on the alternator bottom bolt than I did with every other part of the entire job..!! :crazy:
 

MAY03LT

Member
Nov 18, 2011
3,412
Delmarva
Awesome, thanks for letting us know how you made out!:thumbsup::cool:
 

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