Any one know of a part number that would be an upgrade for a 98 automatic? My dash is reading no more than 12.9. But most of the time in the low 12's. Replace red top with a new yellow top. No change. Have aftermarket stereo with one small amp. Checked cables and alternator. Everything fine. Any suggestions??

 

Be careful here. The '98 alternator must be the one made in France. The one made in Mexico will not work properly and you'll have all kinds of problems. I can't remember all the specifics on this item, but, I'm sure there are more knowledgeable than I, that can help....

 

Anyone have the part number for one to fit a 98 c5? How about a better than stock one?

 

AC Delco #10246634

 

Thanks..

 

Mine will show lower than normal voltage with high underhood temperatures[ stop and go in 95-100 degree heat]Other than that works just fine.I figure the heat effects some component in the built-in regulator.These cars are famous for the amount of underhood heat build-up.Front cylinder is just inches away from the alternator

 

Page Evil Twin! He is the alternator GOD!!! If he doesnt know it about alternators, it doesnt exist!!

I believe that you have other problems other than the alternator. There have been lots of people with the same complaint. Recommend that you check the voltage at the battery terminals with the car running and then at the back of the alternator (big red wire) and see what voltage that you find. I bet that it will be in spec. I have been wanting to get into the service manuals to try to figure out what causes this issue. i guess this gives me a good excuse!

You can have the electrical system tested at any of the large auto parts chains. If I ever need to have my alternator replaced, i plan on having the OEM one that came on the car rebuilt by a local alternator/starter repair shop. We have a couple of EXCELLENT shops in the area.


If I get a chance, I will investigate and if i find anything, i will post it.

BC

 

If you have the original alternator, it is clutch-less, newer C5 with automatic came with a clutch at the pulley to address belt squeal when putting in and out of gear. You have a Valeo 110 amp alternator made in France... it is a good unit. Your specs seem to be OK. The alternator is not your everyday alternator, it communicates with your PCM, the PCM that came with your car.,. GM cam up with a clutch type A4 alternator with 140 amps, made in Mexico... the alternator works OK, but does not communicate well with your pre 2000 PCM. Many people experience charging system fault messages with this unit..The PCM thinks it is a 110 unit.
AS our Resident Electrical guru has mentioned, and I concur, if you have a problem with your alternator, the PCM will flash you a message stating you have a "charging system fault".,.,.If you do not have this, then I suspect you are ok...
The latest word I heard from the people who sign my pension check is that they have a fix for this: and its is the new clutch 140 amp alternator, and a PCM reflash.... But to be honest... this is from the same group that said they have a fix for the column lock... If I were you, I would never give up my original alternator.
You have a smart alternator, here is how it works:

The L-terminal circuit from the generator is a discrete circuit (a discrete circuit has no splices and only one source and destination) into the PCM. The PCM applies ignition voltage to the generator L-terminal circuit. A small amount of current flows from this circuit through the generator windings to ground to create a magnetic field which starts the generator process. When the generator is at operating speed and producing voltage, a solid state switch for the L-terminal circuit in the generator opens and the PCM detects that the initial startup current flow has stopped.

The PCM expects to detect low voltage on the L-terminal circuit prior to the generator rotating at operating speed and conversely expects the circuit to be at ignition voltage potential when the generator is operational. When the PCM detects a fault (circuit shorted to ground, or circuit shorted to voltage), the Driver Information Center will display Charging System Fault.

The generator has an input to the PCM called the F Terminal to indicate the percentage of total capacity that the generator is producing. This signal is detected by the PCM as a duty cycle from the generator and displayed on the scan tool as a percentage. The PCM can monitor the generators output under all conditions to determine if it is functioning normally.

When there is low demand from the electrical system on the generator, a low duty cycle percentage will be displayed. As more accessory load is placed on the generator, the duty cycle output detected by the PCM will approach 100 percent. A normally functioning generating system will never reach 100 percent as indicated on the scan tool.

The L and F terminals are the red and grey

I tried to make this as simple as possible so those thinking 1960's/70's alternators/gen will throw all that old stuff away, clear their head and rethink smart alternator/gen. systems.

Thanks Bill Curlee for the vote of confidence...

Good Luck
Bill aka ( ET )

 

If you have the original alternator, it is clutch-less. Newer C5's with automatic ( A4) came with a clutch at the pulley to address belt squeal when putting in and out of gear. You have a Valeo 110 amp alternator made in France... it is a good unit. Your specs seem to be OK. The alternator is not your everyday alternator, it communicates with your PCM, the PCM that came with your car.,. GM came up with a clutch type A4 alternator with 140 amps, made in Mexico... the alternator works OK, but does not communicate well with your pre 2000 PCM. Many people experience charging system fault messages with this unit..The PCM thinks it is a 110 unit.
AS our Resident Electrical guru has mentioned, and I concur, if you have a problem with your alternator, the PCM will flash you a message stating you have a "charging system fault".,.,.If you do not have this, then I suspect you are ok...
The latest word I heard from the people who sign my pension check is that they have a fix for this: and its is the new Mexican made clutch driven 140 amp alternator, and a PCM reflash.... But to be honest... this is from the same group that said they have a fix for the column lock disaster... If I were you, I would never give up my original alternator.
You have a smart alternator, here is how it works:

The L-terminal circuit from the generator is a discrete circuit (a discrete circuit has no splices and only one source and destination) into the PCM. The PCM applies ignition voltage to the generator L-terminal circuit. A small amount of current flows from this circuit through the generator windings to ground to create a magnetic field which starts the generator process. When the generator is at operating speed and producing voltage, a solid state switch for the L-terminal circuit in the generator opens and the PCM detects that the initial startup current flow has stopped.
The PCM expects to detect low voltage on the L-terminal circuit prior to the generator rotating at operating speed and conversely expects the circuit to be at ignition voltage potential when the generator is operational. When the PCM detects a fault (circuit shorted to ground, or circuit shorted to voltage), the Driver Information Center will display Charging System Fault.

The generator has an input to the PCM called the F Terminal to indicate the percentage of total capacity that the generator is producing. This signal is detected by the PCM as a duty cycle from the generator and displayed on the scan tool as a percentage. The PCM can monitor the generators output under all conditions to determine if it is functioning normally.

When there is low demand from the electrical system on the generator, a low duty cycle percentage will be displayed. As more accessory load is placed on the generator, the duty cycle output detected by the PCM will approach 100 percent. A normally functioning generating system will never reach 100 percent as indicated on the scan tool.

The L and F terminals are the red and grey

I tried to make this as simple as possible so those thinking 1960's/70's alternators/gen will throw all that old stuff away, clear their head and rethink smart alternator/gen. systems.

Thanks Bill Curlee for the vote of confidence...

Good Luck
Bill aka ( ET )

 

No bad mesages. So I will stay with what I have and be thankful .

 

Hi ET!
Would it be normal is see something below 14 volts on the DIC?
I find at highway speed, I see the 14 volts which I understand to be normal but a slow stop and go I normally see something in the 13 to 13.5 range. I have an 04 coupe with the A4 trans.
Thanks

 

See,, I told you he was the alternator GOD!!!!!!
I saved that POST in my C5 stuff to know file!!

BC

 

Like I said, you have a smart alternator, your range is fine.... and if it were not, your alternator would tell you.

 

Thanks for the writeup. I'll save this for future reference. Bill Curlee was right on! You have it nailed but good!

 

Hey ET do you think when the time comes, your better off to have the stock one rebuildt?

 

absolutely