My altenator is on its way out again for the 3rd time in a year. Its gotta be something else causing my probs. A week ago it started whistleing, few days after that I would notice the voltage gauge drop by half when I slowed down, and the blinkers would be oh so slow. Once I get on the gas again all is good. I also noticed the alt. gets real hot to the touch, and my belt is wearing off. It almost seams like the belt is to tight.
How do you check for a bad belt tensioner? all my pully bearings are good.
Is it normal for the alt housing to get so hot?
Any ideas what my prob may be?

its a 95 blazer
Thanks
Jason

 

nobody. [sm=feedback.gif]

 

I think your on the right track. Belt being too tight will put tons of strain on the alt bearings. I hope your bought a lifetime alt. Replacement is free.

I would also get your battery tested. A dead cell could go unnoticed for a long time, yet it will eat alt. Check the connectors on the battery as well. A poor connection could cause problems too.

 

Hanr3 thanks for the input. didn't know the battery could kill an alt.

Here is where I'm at, I priced the tensioner at $125+tax, ouch. new alt $280+tax, oooouuuuuucccchhh. (GM dealer)

I replaced the belt and either the old belt was wrong or really stretched. No improvement there. Still whistles and voltage drops.
I noticed some play in the tensioner when I changed the belt. I am also haveing another alt rebiult as I type. $125

I will put it on tonight and we'll see what happens.

 

Jman,

Hopefully this will help, the belt should be loose enough to fit over all the pulleys shown and still have about 2-3in of slack for the tensioner to take up. That is what I had when I replaced my belt couple years ago...

Also there are two styles of bearings used in the cases for the altenator, one is needle bearings (more prone to failure), the other is sealed roller bearings (less prone to failure). The needle bearing rear case has what looks like a metal plug inserted in the center of where the bearing sits, the sealed roller bearings look like a solid cast housing with a small vent hole in the center.

Here is a picture of the belt routing information without A/C (1), with A/C (2) from the GM Service Manual:

[IMG]local://upfiles/1127/06EA8A7C67BB4BC093F3BE4A063D5EBD.gif[/IMG]

[IMG]local://upfiles/1127/75A6006213D543D0A63CD699A34934B7.gif[/IMG]

 

If you are having a problem with bearings goin bad, bosch alternators have a bigger bearing in the back thats not suppose to go bad. I would also do a voltage drop on the wires to make sure you arent overloading the alternator becase of a crappy connection.

 

Ok I got the Rebuilt alt back and the thing looks like brand new. I'm impressed. It cost me $142.00 after tax.
I put that on, cleaned all conections, and put the Battery from my car into the blazer, and Everything is working great again. I forgot I had an amp and sub in the back. What a noticeable differrence.

I'm going to get my batt tested to see if that was the culprit or not.

 

Amp and sub, eh?

Did you know that the alternator output changes with engine rpms? The faster the engine the higher the output, up to a point. City driving with low rpms, and cranking the sub/amp can overload an alternator. You may need to step up to a higher output alt.

 

What alternator did you get? stock replacement? When this one goes out, spend the extra and and get atleast a 140amp. I had one it lasted me 11 years, on a daily driven high hp v8.