Question...and before you ask, no, I don't have a service manual. I'm removing the alternator to get it checked out, is it as straightforward as it looks? Disconnect the battery, disconnect the leads to the alternator, use the tensioner to remove the belt, remove the adjustment bolt on top and the lower bolt underneath? Anything else have to be removed or just lift the alternator out? Thank you...

 

That's it! Simple and easy.

 

Quick note for the "lift it out" part. Move it to the rear about a foot before lifting it, to get lots of clearance.

 

You got it, simple as that. I just did mine (upgraded to a Mechman 240 amp) a month ago and took all of 10 minutes.

 

O.K., removed, checked and put back in, no problems at all. The alternator shop said all is good, putting out plenty of power and the bearing is fine, he said their usually good for about 70K miles so I'm less then half way there. He also said it's a 160 Amp alternator, he asked if it was ever changed out and I know it wasn't. He was surprised they came stock on an '05 Z51 A4...thanks again to all!

 

My '08 alternator died at 800 miles. The OEM replacement made it to 52K and now the aftermarket stock replacement has 92K and is still good as of today.

 

The alternator on the C6 was one of the easiest of any car I'ved owned to replace.

I say this as someone who had to replace three alternators in one week. One on my 2003 Ram truck, on on my '05 Vert, and one on my '06 Focus. Yes, all three failed at the same time. Kinda sucked!

The truck was tricky, but doable. The Focus was expensive because there was no way I could get in there on that sideways engine, so had to have it towed. Upwards of $600 bucks to have done.

The '05 Vette took about five minutes to replace (Ok, maybe ten,). Easy peasy!

 

i had a 85 Fiero V6 and you will hate life after changing that alternator.

 

I think just owning a Fiero would make me hate life.

 

Just knowing that GM actually made a Fiero makes me want to just spit!

 

Hold on there cowboy... I bought a 1st year 84 Fiero brand new back in the day & loved that car, black with gray interior & a 4sp manual tranny, I kinda liked that car for what it was

 

and to think the speculation on the new mid-engine platform has nothing to do with the idea that GM previously made a similar version called the Fiero in the 80's................

if they only could have gotten the suspension right when released it may have had a longer lifespan.................... or the cracking exhaust manifolds on the V6 versions.....................

worked at a Pontiac dealer at that time..............

 

If you are having charging problems, and the alternator is checking out fine, bank that either the alternator cable where it bolts to the starter solenoid has problems, Right above the starter solenoid where the negative battery cable bolts to the engine block has problems, the battery cable terminals need to be cleaned, the fuse block cable terminal needs to be cleaed, or that someone changed out the spark plugs or spark plug wires to after market units and this is causing the problem.

On the plugs and wires, the OEM units have a higher resistance that works to suppress RF noise back through the ignition coils to the ECM instead. Hence without the RF noise suppression, the rf feed back from the coil in the electrical system causes problems with the ECM not maintaining the alternator to put out the correct voltage to begin with (ECM ends up controlling the alternator at a lower voltage instead.

As for a quick check of the electrical charging system,
car idling,
Should have 14.7V from the rubber boot terminal on the back of the alternator to the body of the alternator when checked with a multimeter.
Same terminal on the back of the alternator as the positive source, to the battery negative terminal should be 14.7V as well. If you have a voltage drop during this second test, then the problem is the negative cable bolted to the engine block.

Both the connection point of the alternator wire to the battery cable end at the starter, and the negative cable to the engine block.


Moving down line past the alternator, battery terminals should have a voltage reading of around 14.5V across its two terminals. If you have a lower reading, then use the body of the alternator as your negative source. If still a lower reading using it, them the problem is the connection point of the alternator cable to the battery cable on the starter solonid.

Last check under the hood, flip open the fuse box, use that positive terminal as your positive source, then first the battery negative post, then the alternator body again. Here, should still be at 14.5V.

As once you have check the above voltages under the hood and the above voltages correct, switch the DIC over to voltage and it should read 14.3V.

Hence alternator should be putting out 14.7, slight loss through the charging system cables to end up with 14.5 at the battery itself, then the final voltage at the ECM of 14.3 volts.
Note, the DIC is not telling you the voltage at the dash, it telling you the voltage at the ECM instead. The Dash is all digital, and it gets is signal for read out from the ECM.

If you do have the above voltages under the hood, but the DIC is showing a lot less than 14.3V, then the problem is from the engine fuse block, through the BCM, then to the ECM. Hence ECM get is power from the BCM, and the BCM gets it power from the engine fuse block.
Note, the alternator uses three power sources for sensing. It has it own fuse in the engine fuse block, uses the power off the horn fuse for the second source, then the power line from the ECM; with the ECM as the main voltage controller. This is the reason for if you do have RF noise in the electrical system from the coils from after market spark plugs or wires, the ECM will control the alternator at a lower output voltage, Hence if you don't have 14.7V at the alternator test with the engine idling, then bank that either one of the two engine block fuse are blown, or after market plugs and wires causing the problem instead.
If this is the problem, then it a pretty easy fix that should not take you long to pull/clean/dielectrical grease the connectors between the parts.

 

I test drove a new one back then, but didn't buy it. Not because I didn't like it, but because I didn't need a toy back then.

 

Thanks Dano, I know you're the "go-to" electrical guy on the forum, I appreciate the help. I'm gonna print your post out, disconnect the battery and do a step by step to clean all the grounds, terminals, etc. Other then one incident a bunch of years ago in 100* weather and VERY slow stop and go traffic (motor stumbled some, DIC went down to 11 or so and car was running hotter then normal) everything seems to be fine, never left me stranded, even on that one day. I use the DIC for voltage readings and some time it seems to be low, I'll have to check all the grounds and hook up a meter and see what the actual readings are. At least I now know the alternator is good...thanks again!

 

No worries, and just take the readings at the areas I listed with the car idling, and post them.

As stated, the alternator should be putting out 14.7V, and the farther you get away from it down the cables, the slightly lower voltage at those points due to the drop through the wires. There are enough points in the electrical system to check as you move away from the alternator (base line of 14.7v), and it will become evident at one of these checks where the problem lies.