BMW Engine Coolant Thermostat Assembly (Heat Management Module)

OEM Replacement – Part Number 11538642559
Fits BMW Models with B58 / B58B30 Engines (2019–2026)
 

Upgrade your BMW’s cooling system with this OEM-spec Heat Management Module (Coolant Thermostat Assembly). This unit is manufactured to match BMW’s original design specifications but is not a Genuine BMW-branded part. It offers precise control of coolant flow for modern B-series engines and restores proper temperature regulation for optimal engine performance.

This OEM unit includes the required sealing O-rings and gaskets for installation. 

Key Features

• OEM-Spec Replacement – Matches the function and design of the original BMW part

• Not Genuine BMW – Third-party manufactured to OEM standards

• Includes O-Rings & Gaskets – Ready for installation

• Precision Temperature Control – Supports rapid warm-up and efficient cooling

• Designed for BMW B58/B58B30 Engines

• Direct Fit Replacement

• NO WARRANTY PROVIDED UNLESS FITTED BY RMI APPROVED WORKSHOP

Product Description

This Heat Management Module (HMM) is an electronically controlled coolant thermostat used in BMW’s B-series engines. Instead of a simple open/close valve, it uses a rotary coolant control valve that adjusts flow dynamically for precise heat regulation.

Common Symptoms of Failure

• Engine overheating

• Engine running hotter than normal

• Long warm-up time

• Cooling system fault messages

• Diagnostic codes: 20F220, 20F206, 20A704

Replacing a faulty HMM restores correct coolant circulation and helps prevent engine damage.

Vehicle Compatibility

BMW X5 (G05) – 2019–2023

• xDrive40i (B58B30M0)

• sDrive40i (B58B30M0)

• xDrive45e (B58B30M1 – PHEV)

BMW X7 (G07) – 2019–2022

• xDrive40i (B58B30M0)

BMW 540i / 540i xDrive – 2020–2023

• RWD & AWD

• Gas and Mild Hybrid versions

• Engines: B58B30M0 / MHEV

BMW 740i / 745e – 2020–2022

• 740i / 740i xDrive

• 745e PHEV

BMW 8 Series (840i / 840i xDrive / Gran Coupe)

Models 2020–2026

• Coupe, Convertible, Gran Coupe

• B58B30M0 engines

BMW M340i / M340i xDrive – 2020–2024

• B58B30O1 engines

• RWD, AWD, and MHEV models

BMW X3 M40i – 2020–2024

• B58B30O1

BMW X4 M40i – 2020–2025

• B58B30O1

BMW X6 40i – 2020–2023

• B58B30M0 engines

BMW Z4 M40i – 2020–2026

• B58B30O1 engines

BMW M240i / M240i xDrive – 2022–2025

• B58B30O1 / B58B30M0 engines

Package Includes

• 1 × OEM Engine Coolant Thermostat Assembly (Heat Management Module)

• Included: O-rings & gaskets

Important Notes

• This is an OEM replacement, NOT a Genuine BMW part

• Professional installation is recommended to activate warranty

• Always verify fitment using your vehicle’s VIN