The Mercedes GLS 450 should use a Mercedes-Benz approved coolant that meets MB 325.0 (and MB 326.0) specifications; commonly available options include the pink Glysantin G48 or other MB 325.0-compatible coolants. Always verify the exact specification in your owner's manual or with a dealer before purchasing.
Why the specification matters
Modern Mercedes-Benz cooling systems are built with aluminum components and rely on a long-life, organic acid technology (OAT) coolant. Using an approved coolant protects the engine, radiator, and thermostat from corrosion and overheating while ensuring the warranty remains valid. Mis-matching coolant types or using non-MB-certified products can lead to reduced protection and potential leaks or deposits.
What to buy for the GLS 450
Below are common, MB-approved options that typically satisfy the MB 325.0/326.0 standards. When in doubt, choose a product explicitly labeled as MB 325.0-compatible or MB 326.0-compatible and Mercedes-Benz Genuine Coolant.
- Mercedes-Benz Genuine Coolant (50/50 premixed, MB 325.0 compatible)
- Glysantin G48 (pink), a long-life OAT coolant that meets MB 325.0 compatibility
- Other MB-approved coolants that explicitly state compatibility with MB 325.0/326.0 on the label
If you have a specific product in mind, check the packaging for an MB approval statement or consult your dealer to confirm compatibility with the GLS 450’s cooling system.
Top-up and replacement guidelines
When topping up or replacing coolant, follow these steps to ensure proper protection and avoid damage to the cooling system.
- Wait until the engine is cool before opening the cooling system cap to prevent scalding and pressurized spray.
- Locate the expansion tank and check the current coolant level against the markings on the reservoir.
- Use only MB-approved coolant that is MB 325.0/MB 326.0 compatible. If you’re using a concentrate, dilute it with distilled water to the recommended 50/50 premix unless you’re starting with premixed coolant.
- If topping up, add the same type and concentration as the existing coolant to avoid chemical incompatibilities.
- Avoid mixing different coolant chemistries (e.g., silicate-based with OAT) as this can form deposits and reduce cooling efficiency.
- After topping up, run the engine to operating temperature with the radiator cap off briefly to purge air, then recheck the level and replace the cap securely.
- If the system has been drained or if you suspect contamination, have the cooling system flushed and refilled with MB-approved coolant by a qualified technician.
Consult your service advisor for the proper flush procedure and to ensure the replacement interval aligns with your vehicle’s maintenance schedule. Improper handling or using the wrong product can compromise cooling performance and warranty coverage.
Summary
For the Mercedes GLS 450, rely on a Mercedes-Benz approved coolant that meets MB 325.0 (and MB 326.0) standards. Common choices include Mercedes-Benz Genuine Coolant and Glysantin G48, both MB 325.0-compatible. Always verify compatibility, avoid mixing different coolant types, and follow the vehicle’s service intervals or consult a dealer for professional help when performing a full coolant replacement.