Symptoms
Coolant loss with no obvious puddle, coolant crust or a sweet smell near the turbos, low-coolant warning, overheating. An MBWorld owner of a 2014 G 63 found a cracked coolant line at the driver-side turbo.
The fix, step by step
- Pressure-test the system to find the leak.
- Replace the turbo coolant feed and return lines as a set, and on a high-mileage engine do the water pump and thermostat housing at the same time.
- FCP Euro calls the lines 'a common failure item that can lead to coolant loss and engine overheating.' Access is tight.
- MBWorld owners disagree on whether it's a sensible DIY, so plan to remove intake parts.
Tools & part numbers
- Cooling-system pressure tester
- hose-clamp pliers
- flare and line wrenches
- MB 325.6 coolant
- vacuum fill tool helpful
Where to buy the parts
Rein M278/M157 turbocharger coolant line repair kitFCP Euro ↗Amazon ↗
Genuine Mercedes M157 water pump, thermostat housing & turbo coolant line kitFCP Euro ↗Amazon ↗
Genuine Mercedes coolant, MB 325.6, 1 galFCP Euro ↗Amazon ↗
Hunting a used or discontinued part? Search eBay Motors for Mercedes-Benz G 63 AMG parts →
Rated for a competent home mechanic with a decent tool kit. Confirm torque figures, fluids and procedures against the factory service manual for your VIN, support the truck on stands rather than a jack, and work at your own risk (disclaimer). Some parts links are affiliate links, which pay us a small commission at no cost to you.