Mahle Alternator 12V 100A MG58

The Mahle alternator listed here is a 12V, 100A unit, supplied new and identified with part number MG58. It is a single-leg alternator with an internal regulator, and it is listed without a belt pulley. Those details matter when you are matching the unit to the existing mounting arrangement and charging setup.

Key mounting dimensions include a 51mm mount leg thickness, 86.0 mounting points diameter, and 50.8 mounting bores distance, with 11.5mm adjusting hole and pivot hole diameters. The alternator is noted as having battery temperature sensing, dust-proof construction, and insulated ground, so the installation and electrical interface should be checked against the existing equipment before ordering.

This part is listed under MAHLE and carries the description Mahle Alternator 12V 100A. The stated charge current is 100A, and the unit is covered by a one year warranty. As with any alternator replacement, the safest approach is to confirm the part number, voltage, mounting style, and pulley arrangement before fitting.

Key Features

• 12V alternator with 100A charge current
• New unit, supplied each
• Internal regulator
• Single-leg alternator mount
• Without belt pulley
• Battery temperature sensing

Specifications

• Brand: MAHLE
• Part No.: MG58
• Product type: Alternator
• Voltage: 12V
• Power rating: 100A
• Alternator mount: Single Leg
• Regulator type: Internal
• New / Reman.: New

Fitment information provided

• Volvo Marine/Penta AD31B
• Volvo Marine/Penta AD31B 1990
• Volvo Marine/Penta KAD42A
• Volvo Marine/Penta KAD42A 1993
• Volvo Marine/Penta TAMD31M
• Volvo Marine/Penta TAMD31M 1986

Application and Buying Notes

Before ordering, match the part number MG58 against the alternator being replaced, then check the mounting layout against the supplied measurements. The key fitment points here are the single-leg mount, 51mm mount leg thickness, 86.0 mounting points diameter, 50.8 mounting bores distance, and 11.5mm adjusting and pivot holes. If any of those differ, the unit may not physically line up as expected.

The electrical specification is equally important. This is a 12V alternator with a 100A charge current and an internal regulator, so it should be compared with the existing charging system rather than assumed to be interchangeable with a different voltage or output rating. The listing also notes battery temperature sensing and insulated ground, which are worth confirming against the vehicle or marine installation before purchase.

The pulley arrangement needs attention as well. This alternator is listed without a belt pulley, so if the existing unit uses a specific pulley setup, that part will need to be confirmed separately. The product is marked as new rather than remanufactured, and it is backed by a one year warranty, but correct physical and electrical matching still comes first when replacing an alternator.

If you are working on a Volvo Marine/Penta application shown in the fitment list, use the application details alongside the part number MG58 to narrow the match. Where a replacement alternator sits in a marine charging system, small differences in mount style, pulley arrangement, or regulator type can matter just as much as voltage and amperage.

For best results, compare the old unit side by side with the listed dimensions and features before fitting. That approach helps avoid the common problems of misaligned mounts, pulley mismatch, or a regulator configuration that does not match the original system. If there is any uncertainty, verify the application details and measurements before you commit to the purchase.

Before supply, the safest approach is to confirm the original unit details against the listed part number, voltage, output rating, mounting arrangement, and pulley configuration. That checking process is standard practice in the parts trade because visually similar units can still differ in service-critical ways.

For workshop, fleet, and equipment applications, accurate identification of part number MG58 helps avoid unnecessary freight, additional labour, and vehicle or machine downtime. Where the application is not straightforward, the original unit, OEM reference, or workshop records should be used as the primary confirmation point.

Relevant published details for this unit include Type ALTERNATOR, Unit of Measure EACH, Warranty One Year, Mount Leg Thickness 51mm, Power Rating (Amp) 100, Suits Unit Make Mahle, Note Battery temperature sensing. Dust-proof. Insulated ground, New / Reman. New, Pulleys without belt pulley, Mounting points diameter 86.0.

Additional published details for cross-checking include Packaging width 18.60, Net Weight 5075, Product Group 1 ROTATING ELECTRICAL, Part No. MG58, Brand MAHLE, Description Mahle Alternator 12V 100A, Adjusting Hole Diameter 11.5, Pivot Hole Diameter 11.5, Regulator Type Internal, Voltage 12.

Mahle Alternator 12V 100A. Part number MG58 should be checked first. Listed voltage is 12. Listed output rating is 100. These details form the core reference points used by parts interpreters when confirming the correct replacement.

Mount style is Single Leg. Regulator type is Internal. Those physical and electrical details should line up with the original unit before the replacement is approved for fitment.

For part number MG58, the normal identification sequence is part number, electrical rating, mounting arrangement, connector or terminal style, and pulley or drive details. Using those checkpoints helps confirm that the listed unit matches the service requirement rather than only looking similar.

Compatibility note: Please confirm fitment using part number MG58, the 12V 100A specification, the single-leg mount, and the listed Volvo Marine/Penta application details before ordering. Do not rely on the description alone if your original alternator differs in pulley setup, mounting dimensions, or regulator type.

FAQ

What is the part number for this alternator?

The part number listed is MG58.

What voltage and output does this alternator have?

It is a 12V alternator with a 100A charge current.

Does this alternator come with a pulley?

No. It is listed without a belt pulley.

Is the regulator internal or external?

The regulator type is internal.

What fitment applications are provided?

The provided applications include Volvo Marine/Penta AD31B, KAD42A, and TAMD31M, including some model-year references such as 1990, 1993, and 1986.

What should I check before buying?

Confirm the part number MG58, the 12V 100A rating, the single-leg mount, the 51mm mount leg thickness, and the pulley arrangement against the unit being replaced.