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July 29, 2025 Service bulletin

Coolant level warning in instrument cluster

Mercedes-Benz technical service bulletin LI20.30-P-078666 for 2025 Mercedes-Benz GLS 450 4matic, 2025 Mercedes-Benz Gle 350 4matic and 2025 Mercedes-Benz Gle 450 4matic and others.

Bulletin number
LI20.30-P-078666
Component
Engine
Summary
Complaint Coolant level warning in instrument cluster. Coolant odor or leaking from coolant expansion reservoir. Cause Coolant wicking through electrical contacts, or level sensor electrical connections not present in expansion reservoir. Remedy 1. Inspect expansion tank level sensor electrical connection for wicking coolant or missing contacts. Additionally the triangular sticker may not be present on top of reservoir. See example of OK and NOK part. 2. Replace expansion reservoir if level sensor contacts are confirmed to be missing or wicking coolant. 3. Repair any damage to wiring or electrical contacts on wiring harness. 4. Create a TIPS case with supporting photos and submit to the IFQ inbox for information. Vehicle can be released after repair is complete.

Owners of these vehicles have filed 7 complaints in the engine category.

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