Correct Battery for 325is?

[cory58]

My recent barn find 325is didn't come with a battery. Figured I would use the battery from the cabrio or touring until I figure out whether to part it out, but the polarity is reversed. All the auto parts stores list group 90 or 91 batteries for a 1989 325is, but those have the same polarity as my cabrio/touring batteries.

I've never had an E30 with the battery in the trunk. Does the factory set up have the positive cable to the front (closest to the wheel well) and negative cable to the rear (closest to the tail light)? If so, what is the correct battery?

Thanks, Cory

[Vincenze]

The Group 49 or H8 battery fits.
The smaller Group 48 one also fits.

The rear cable is -, the front is +.

Also, there is a battery venting pipe in the trunk.

[roguetoaster]

In fairness, I don't think the correct vented battery with useful terminal placement and the hold down foot is actually still in production for the US market, even though they are still listed. Whatever the case, a sealed battery with a custom hold down would be the better way to go.

[Vincenze]

I checked a few batteries at Autozone, they had holes for the venting elbow.
The elbow is available: 61211377835. Autozone, etc also sell it.

[roguetoaster]

You looked at actual batteries on the shelf, or online images? Maybe it's location dependent, but in the DC region I have never seen one at auto parts stores or big box places.

[Vincenze]

You looked at actual batteries on the shelf, or online images? Maybe it's location dependent, but in the DC region I have never seen one at auto parts stores or big box places.

I bought one.
Duralast Gold, Made in Germany.

It's not my image, but the hole is there.

[Vincenze]

The Costco Interstate H8 battery also has a red plug.

[cheffy30]

never used a vented battery in my car. sent from hell using Tapatalk

[roguetoaster]

The Costco Interstate H8 battery also has a red plug.

Odd, I asked at two different Costcos and both times they said they could not order the battery I requested.

[Vincenze]

never used a vented battery in my car. sent from hell using Tapatalk

Many batteries spew acid even if manufacturers attest that they are maintenance-free.
The body under the trunk battery is a rust-prone area in the E30 due to that acid.

[z168]

got this over the weekend. the dealer couldnt match it by part number so we physically compared the ratings and I ended up with this

[cory58]

Thanks for all the replies!

The long hold down rod is in stock at FCP and they can get the plate from BMW in 2 days. To be fair, I think the original parts have been superceded by similar parts from newer models.

The well below the battery is rusted out and all the plastic parts are gone from the well except the tray, so I have a few follow-up questions.

1. There is a metal plate underneath the tray that the long fold down rod screws into. I cannot find that plate on RealOEM diagrams. Can anyone point me in the right direction. I can post a pic of the rusted out one from the car if needed.

2. Where is the expansion tank (part #11 in the RealOEM diagram above) supposed to be located?

Thanks, Cory

[cheffy30]

no acid. no water. no rust. just sayin. gotta keep the booty clean! sent from hell using Tapatalk

[Vincenze]

Thanks for all the replies!

The long hold down rod is in stock at FCP and they can get the plate from BMW in 2 days. To be fair, I think the original parts have been superceded by similar parts from newer models.

The well below the battery is rusted out and all the plastic parts are gone from the well except the tray, so I have a few follow-up questions.

The replacement metal for the battery tray is available.
It's often rusted due to acid dripping.

This one is for cars before 1987 https://catuned.com/rear-battery-box...ith-all-e30-m3

The part that you're looking for is probably unavailable from BMW, so you should also look for a replacement.

https://www.facebook.com/E30garageNorway/

The expansion tank is up in the wheel well hidden by a plastic cover.

[cory58]

no acid. no water. no rust. just sayin. gotta keep the booty clean! sent from hell using Tapatalk

I refer to the car as a "barn find," but it was more like a "field find." The seller said he parked it when it ran out of gas in 2006, and the rust in the trunk was from a failed trunk gasket. Not so sure about that. The only rust is in the battery well (bad) and at the bottom of the bulkhead between trunk and back seat (not so bad). The trunk was really dirty but the jack well and spare tire well are fine.