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      07-07-2026, 09:01 AM   #23
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Quote:
Originally Posted by sxychubles View Post
Went for two drives yesterday. Sensor read once 4-5min after engine was at operating temp. Was not able to get a second reading after forcing it (waited about 6-7min). One thing I did notice was the previous sensor read a little sliver below the min mark where as this one shows nothing below the min mark. I think I'll add 300mil and see if it reads it, at this point I feel the car was low on oil due, somehow.
Is the dash level indicator showing "+1" or something else?
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      07-07-2026, 09:03 AM   #24
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Plus one quart. +1
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      07-07-2026, 09:14 AM   #25
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voltage regularator on the alternator can sometimes cause this issue with oil levels not reading.
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      07-07-2026, 10:55 AM   #26
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What is the voltage measured across the charging terminals under the hood when the engine is idling?
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      07-07-2026, 12:02 PM   #27
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it fluctuates lowest was 12.6 highest was 14.3.
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      07-07-2026, 01:51 PM   #28
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Quote:
Originally Posted by sxychubles View Post
it fluctuates lowest was 12.6 highest was 14.3.
Aha - then as omgzirra_exe said above it could very well be the alternator regulator causing issues with the sensor calibration and stored readings. If I recall correctly, a good S65 alternator puts out between 13.8 and 14.4 volts at idle.

The Test: With the engine running, a perfectly healthy S65 alternator should read a steady 13.8V to 14.4V. If you see it holding strong in this range with the A/C and headlights on, your alternator is in good health.
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      07-07-2026, 02:00 PM   #29
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Quote:
Originally Posted by DrFerry View Post
Aha - then as omgzirra_exe said above it could very well be the alternator regulator causing issues with the sensor calibration and stored readings. If I recall correctly, a good S65 alternator puts out between 13.8 and 14.1 volts at idle.
yeah, and if you are going to replace it, i def recommend spending the money on OEM, and not valero in some cases. even if its "OEM" Supplier.

Normally my rule of thumb is Electrical = always oem
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      07-07-2026, 03:21 PM   #30
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I doubt the original alternator has ever been replaced. Kind of in the mind to replace the entire thing at this point.

Price different is quite staggering and lots of people seem to have no issues with the valeo which is an oe supplier.
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      07-07-2026, 03:25 PM   #31
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Quote:
Originally Posted by sxychubles View Post
I doubt the original alternator has ever been replaced. Kind of in the mind to replace the entire thing at this point.

Price different is quite staggering and lots of people seem to have no issues with the valeo which is an oe supplier.
You can replace just the voltage regulator, but after going through all that work, I'd probably just replace the entire alternator.

I'm also not sure how much room you'll have to get the regulator off. The brushes have to be retracted during installation, otherwise you won't be able to slide it over the commutator.

Personally, I've had a Valeo alternator fail after about a year, and I've had a handful of other "OE supplier" parts fail within a similar timeframe too. At this point, it almost feels like luck of the draw with some of these aftermarket OE replacements.
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      07-07-2026, 03:26 PM   #32
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Quote:
Originally Posted by omgzirra_exe View Post
yeah, and if you are going to replace it, i def recommend spending the money on OEM, and not valero in some cases. even if its "OEM" Supplier.

Normally my rule of thumb is Electrical = always oem
Check it, FCP euro's photo of the OEM alternator has a valeo stamp on the back.

https://www.fcpeuro.com/products/bmw...0a-12317838656

But to your point, I try to stay genuine as much as possible. But in this instance it seems wild. I went 034 front control arms in January to save 600 dollars, guess who is getting ready to replace the control arms, cars drove 1000 miles on them.
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      07-07-2026, 03:27 PM   #33
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Quote:
Originally Posted by omgzirra_exe View Post
You can replace just the voltage regulator, but after going through all that work, I'd probably just replace the entire alternator.

I'm also not sure how much room you'll have to get the regulator off. The brushes have to be retracted during installation, otherwise you won't be able to slide it over the commutator.
Annoyingly enough, i just went through and replaced all the pulleys, belts, all the ps lines, coolant hoses, cooler lines, vanos covers, valve covers. I remember looking at the alternator and thinking, nah you can stay.
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      07-07-2026, 03:35 PM   #34
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Quote:
Originally Posted by sxychubles View Post
Annoyingly enough, i just went through and replaced all the pulleys, belts, all the ps lines, coolant hoses, cooler lines, vanos covers, valve covers. I remember looking at the alternator and thinking, nah you can stay.
I replaced my "OE" Corteco engine mounts twice within a year before giving up and going back to genuine BMW mounts. They've been fine ever since, but this was 2 years ago, probably gonna go Poly now tbh.

Same thing with Bosch O2 sensors. I had a couple that were hit or miss, switched back to genuine BMW sensors, and the issues disappeared.

This definitely isn't the first time I've heard of OE supplier parts being inconsistent. Sometimes it's just bad luck, but the quality seems to be all over the place.

That said, I still think replacing the alternator is going to solve your issue and yes I know the BMW OE one is Valeo
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      07-07-2026, 03:39 PM   #35
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Quote:
Originally Posted by omgzirra_exe View Post
I replaced my "OE" Corteco engine mounts twice within a year before giving up and going back to genuine BMW mounts. They've been fine ever since, but this was 2 years ago, probably gonna go Poly now tbh.

Same thing with Bosch O2 sensors. I had a couple that were hit or miss, switched back to genuine BMW sensors, and the issues disappeared.

This definitely isn't the first time I've heard of OE supplier parts being inconsistent. Sometimes it's just bad luck, but the quality seems to be all over the place.

That said, I still think replacing the alternator is going to solve your issue and yes I know the BMW OE one is Valeo
Yea i just went with the bosch injectors. I went with bimmerworld engine mounts and I absolutely regret that decision. Was going to the corteco soon buuut may just spring for the oem after reading your message. Waiting patiently for the new alternator. Lets see.
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      07-07-2026, 03:41 PM   #36
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Quote:
Originally Posted by sxychubles View Post
Yea i just went with the bosch injectors. I went with bimmerworld engine mounts and I absolutely regret that decision. Was going to the corteco soon buuut may just spring for the oem after reading your message. Waiting patiently for the new alternator. Lets see.
yeah, hope it works out, I know it did for my friend since he was fighting that issue for well over a year after his engine got built.
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      07-07-2026, 04:02 PM   #37
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BOSCH is also an OEM E9X M3 alternator supplier. ECS sells a remanufactured BOSCH unit though new is better.
.
https://www.ecstuning.com/b-bosch-pa...2317837981bkt/
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      07-08-2026, 06:48 AM   #38
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Quote:
Originally Posted by DrFerry View Post
BOSCH is also an OEM E9X M3 alternator supplier. ECS sells a remanufactured BOSCH unit though new is better.
.
https://www.ecstuning.com/b-bosch-pa...2317837981bkt/
DO NOT USE THE REMAN BOSCH UNITS. i went through 3 of them in a year on my 328. I have a new valeo in my M and its been just fine
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      07-08-2026, 06:51 AM   #39
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Quote:
Originally Posted by THRSTYM3 View Post
DO NOT USE THE REMAN BOSCH UNITS. i went through 3 of them in a year on my 328. I have a new valeo in my M and its been just fine
Thanks for your input. Where did you purchase your refurbished Bosch units for your 328?
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      07-08-2026, 07:32 AM   #40
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Quote:
Originally Posted by THRSTYM3 View Post
DO NOT USE THE REMAN BOSCH UNITS. i went through 3 of them in a year on my 328. I have a new valeo in my M and its been just fine
Dang it! I just put in a remanned Bosch ps pump. 👀
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      07-08-2026, 09:03 AM   #41
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Quote:
Originally Posted by sxychubles View Post
Check it, FCP euro's photo of the OEM alternator has a valeo stamp on the back.

https://www.fcpeuro.com/products/bmw...0a-12317838656

But to your point, I try to stay genuine as much as possible. But in this instance it seems wild. I went 034 front control arms in January to save 600 dollars, guess who is getting ready to replace the control arms, cars drove 1000 miles on them.
Found something odd on FCP's website for the refurbished "Bosch" alternator. Two brand names are shown in photos of the unit...
.
https://www.fcpeuro.com/products/bmw...ch-12317837981
https://www.fcpeuro.com/public/asset...-AL9454X-1.jpg
.
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      07-08-2026, 09:29 AM   #42
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Quote:
Originally Posted by DrFerry View Post
Found something odd on FCP's website for the refurbished "Bosch" alternator. Two brand names are shown in photos of the unit...
.
https://www.fcpeuro.com/products/bmw...ch-12317837981
https://www.fcpeuro.com/public/asset...-AL9454X-1.jpg
.
probably just how it's remanufactured.

I might buy a valeo one this month, since i have front of the engine maintenance coming up / pre-sale prep (i say this now, but im really lazy to work on my own car, so i sometimes want to sell as is lmao)
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      07-08-2026, 10:08 AM   #43
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Quote:
Originally Posted by DrFerry View Post
Thanks for your input. Where did you purchase your refurbished Bosch units for your 328?
FCP
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      07-08-2026, 10:10 AM   #44
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Quote:
Originally Posted by sxychubles View Post
Dang it! I just put in a remanned Bosch ps pump. 👀
ps pump should be fine. I have a reman in my M and my 328. 328 has 25k on the reman
The m has about 8k miles on the ps pump
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