Found the E90 320d replacing the E82 120d

DRCraig · Jul 3, 2025

Update time

3 months in with my new alternator and the same battery that experienced overcharge with the old alternator.

I've noticed the rotten egg (hydrogen sulfide) smell again few days ago. Luckily I was in Cape Town, so I took the car to SMG Century City to have them check it out.

I was informed that my battery (2018) is on its wat out (I have not really experienced any electrical issues), hence the alternator is trying to overcharge it.

Bmw quoted me R6.1k for a new battery hoping that thereafter the alternator charge would stabilize to 14.2V.

Is it likely that the old alternator damaged my battery and now it is affecting the operation of the new alternator?

Any advice going forward?

AshG108 · Jul 3, 2025

DRCraig said:
Update time

3 months in with my new alternator and the same battery that experienced overcharge with the old alternator.

I've noticed the rotten egg (hydrogen sulfide) smell again few days ago. Luckily I was in Cape Town, so I took the car to SMG Century City to have them check it out.

I was informed that my battery (2018) is on its wat out (I have not really experienced any electrical issues), hence the alternator is trying to overcharge it.

Bmw quoted me R6.1k for a new battery hoping that thereafter the alternator charge would stabilize to 14.2V.

Is it likely that the old alternator damaged my battery and now it is affecting the operation of the new alternator?

Any advice going forward?

Did you code the battery when the alternator was changed? Coding aligns the battery to accept a new alternator and vice versa from my understanding.
Secondly, does your car have a DP or not because normally that smell is when the cat is blocked.

DRCraig · Jul 6, 2025

AshG108 said:
Did you code the battery when the alternator was changed? Coding aligns the battery to accept a new alternator and vice versa from my understanding.
Secondly, does your car have a DP or not because normally that smell is when the cat is blocked.

Thanks for the response.

Yes, the car has a downpipe, but that burned battery smell is so distinctive. BMW changed the battery and the alternator charge stabilized thereafter. Think the old battery took a knock with the previous prolonged overcharge.

Will monitor closely.

DRCraig · Friday at 12:07 PM

Update

After four years of ownership, I still can’t bring myself to part ways with this car—not that I want to. She’s just ticked over 254,xxx km and is still being kept in tip-top condition for her age.

I’m still commuting 130km weekdays, and the 320d does it without breaking a sweat. There are a few cosmetic bits I’ll sort out as time goes on, like replacing the headlight lenses. Still the best affordable daily imho. No frills, no fuss it just gets the job done.

unobeat · Friday at 12:15 PM

One clean 320d this one and if i looked at its neatness and you told me the mileage.

I would not believe it until i looked at the cluster.

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Found the E90 320d replacing the E82 120d

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