# Service bulletin LI20.30\-P\-078666

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

- Type: Service bulletin
- NHTSA id: 11023363
- Published by NHTSA: 2025\-09\-26
- Manufacturer's number: LI20.30\-P\-078666
- Manufacturer's date: 2025\-09\-25
- NHTSA component: ENGINE

## NHTSA's 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 \*\*Important: If the coolant expansion tank is replaced due to leak at the level sensor contact area, ensure that the expansion tank is marked as the main damage part in the warranty claim 1\- Inspect expansion tank level sensor electrical connection for missing contacts. Additionally the triangular sticker may not be present on top of reservoir. See example of OK and NOK part. • Replace the expansion reservoir if contacts are found to be missing. A TIPS case is not needed. • Proceed to step 3. 2\- With contacts present, inspect coolant level sensor electrical connection for leakage past contact seals. Visible coolant at the connection indicates leakage. • Capture photos if leakage is identified and create a TIPS case with the Powertrain team. • Replace the expansion reservoir. 3\- Repair any damage to wiring or electrical contacts on wiring harness from S41 to N10/6. • Check the front SAM N10/6 for coolant contamination and replace if necessary. • Inspect electrical connectors at base of A\-pillar for contamination and repair/replace as necessary.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2025/MC-11023363-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2025/MC-11023363-9999.pdf)

The document is the manufacturer's. This site does not hold it.

## Components

Engine

## Vehicles listed

- 2025 MERCEDES\-BENZ AMG GLE53 4MATIC\+
- 2025 MERCEDES\-BENZ AMG GLE53 4MATIC\+ COUPE
- 2025 MERCEDES\-BENZ AMG GLE63 S 4MATIC\+ COUPE
- 2025 MERCEDES\-BENZ AMG GLS63 4MATIC\+
- 2025 MERCEDES\-BENZ GLE 350 4MATIC
- 2025 MERCEDES\-BENZ GLE 450 4MATIC
- 2025 MERCEDES\-BENZ GLE 450 4MATIC COUPE
- 2025 MERCEDES\-BENZ GLE 450E 4MATIC
- 2025 MERCEDES\-BENZ GLS 450 4MATIC
- 2025 MERCEDES\-BENZ GLS 580 4MATIC
- 2025 MERCEDES\-MAYBACH GLS 600 4MATIC

JSON: [/v1/bulletins/11023363](/v1/bulletins/11023363)

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