JTB007

I have had my alternator replaced with a rebuilt Valeo about 2 years ago. I am now getting the warning light Batt/Alt. Did the Dyno mode dealio.
12.5
13.1-13.2v at idle
13.0-13.1 at idle w/radio, A/C, headlights and RR defrost on

Thoughts?

mleskovar

12.5v is a healthy battery. What is the voltage across the battery at 2500 rpm? Are the battery posts clean and connectors tight?

JTB007

Took it to AutoZone to at lunch. They tested/checked the battery, guy said it should be 13.5-14.5v at idle. It was @ 13.1v

He said only way he could check Alternator is to take it out. He said in his AZ expertise that it's alternator or wiring.

VVF

Then it's probably the voltage regulator(?). I believe it's possible to change that without removing the alt.

mleskovar

So what is the voltage across the battery at 2500 rpm? Should be about 14.5v. If the voltage is ok then the alternator is ok.

JTB007

Sorry for the tardy reply.

@ 2500 rpm it's 14.1-14.2V

mleskovar

That's enough to keep the battery charged....unless you don't drive much. Check your battery cables at both ends for solid connections and corrosion. You could just have a bad battery.

JTB007

Battery is 100% healthy , my mechanic checked the alternator and it's good. Drove it hard leaving his place and the light came on again. Got on it again and had to stop to make a left turn, almost stalled on me dropped to below 600 rpms for second then back to normal idle. Only thing pulling power were the headlights and radio, windows were down (no a/c).

Must be battery cables..right?? Left it in garage today..a little gun-shy

nlpamg

Sounds like your alternator is failing.

Carsy

Does the light illuminate when you are at idle or at higher revs?

JTB007

The light comes on at different times. Sometimes won't come on for days. Other times during heavy acceleration and other times within 5 minutes of starting it in the morning.

I replaced the alternator a little over 2 years ago with a Remanufactured Valeo with a 2 year warranty. I see that AutoZone has a Duralast with a lifetime warranty, but read on here to use the Valeo. This sucks.

mleskovar

Guessing here but you made reference to running it "hard"....check to see if the hot cables are pinched or worn through and grounding out somewhere. Lots of torque shifts things around in the motor well and there may be a routing problem. If it were losing the ground you would know because different memory dependent functions would reset. Follow the cables the whole length and feel for worn spots. Pull on the cable to check the connectors and make sure they're tight as well. If there is one it should be pretty apparent because it would be arcing and burning the surrounding metal. One trick is to open the hood at night and look around the motor while revving the motor for a 'spark' check.

Carsy

It would be interesting to see the results if an auto electrician could set up an amp meter to your battery whilst you were driving to check for any heavy electrical loads.

JTB007

Had the guy at AutoZone run the test hooked up to the battery. Battery is 100%. Voltage regulator read as having failed. I have a rebuilt Valeo in there that I had out in a little over 2 years ago. (2 year warranty..Nice)

I read on the forum when my last alternator went that a Valeo was a must on my C230K.

This still hold true? thank you - JB

VVF

You probably misunderstood something.
I had a Bosch alt in my 05 C230K.
There seem to be some issues if you replace Valeo with Bosch or vice versa. Some were reporting the car "not taking" the alternator...

JTB007

I remember now. I had a Valeo and was told to only replace with Valeo.

Am i going to have to replace this Valeo alt every two years that comes with a one year warranty? This really sucks

JTB007

My local supplier has it in stock at $190+tax - Valeo

VVF

Look on RockAuto com also. I think I saw some reman Valeos with lifetime warranty there.

JTB007

They want $400 and 12 month warranty, but thank you for the reference

VVF

Try REMY Part # 12459 Premium Remanufactured
w/ Valeo ; 120 Amps (Only 3 Remaining)

It's "a bit" cheaper

I bought Remy Bosch reman. It's been 5 months so far though, but they have lifetime warranty for non-commercial applications.

Or you could just replace the voltage regulator, since you are out of warranty anyway... They are about $60 AFAIK.

nlpamg

The Bosch one does not work in some cars (like mine).

This thread was originally posted in 2010 and my alternator was replaced then. About 35-40k miles have been put on the car and the Valeo alternator (that came from the dealer) still seems to be working fine (knock on wood).

Just go with a new Valeo.

samaritrey

My original Valeo alternator lasted 199,000 miles. when I tired to replace it with a Bosch unit I found that the battery cable would not even connect to the alternator without serious modifications. I found a Valeo alternator on amazon brand new for around $200. Just find the Valeo part number and go to town on google.

Glyn M Ruck

Refer this note from Russell Ormerod.

quote" Originally Posted by Russell Ormerod View Post
Alternators are not what they used to be,
The difference is in the voltage regulators
there are 3 variants MFR (multi function regulators)
LIN (local interconnect bus)
BSS (bit synchronis bus)
BSS and LIN are used depending on the engine ECU type
either ME2.8 or SIM4, these regulators actually communicate with the engine ecu and transfer infomation between each other, the engine ecu has control over the alternater to be able to control the torque loading for emmision requirments.
So you cannot swop an alternator with a BSS regulator with one with say a LIN bus. no communication will take place. " unquote.

Valeo & Bosch alternators are interchangeable but you need to order the correct alternator in each Brand.