Mercedes AMG G Wagon

Mercedes-Benz G-Class : Service Guide

The Mercedes-Benz Gelandewagen, most often called the G-Wagen or G-Class, is a line of high-end SUV’s with some serious credentials. Boasting a robust body-on-frame design, 3 locking differentials, and a range of powertrain options, it is one of Mercedes-Benz’s most popular vehicle.

This is evident by the very long production run, spanning an incredible 40 years with minimal updates along the way. The Mercedes-Benz G-Class Service Guide will act as a great reference for owners looking to properly maintain their vehicle, and also for future owners to understand what and how often are recommended service intervals.

The Mercedes-Benz G-Class started development as a vehicle for military purposes, with the introduction of a civilian version in 1979. Since then, it has had only minor facelifts and interior updates, looking very similar throughout its production run.

A completely redesigned second generation was released in 2018 that keeps the rugged charm that has made it so popular. The Mercedes-Benz G-Class service guide will focus on the first-generation models built after 2012, the last refreshment before the 2018 redesign.

Engine, Oil, Transmission, Clutch

After 2012, the Mercedes-Benz G-Class came with 3 variations: G550, G63 AMG, G65 AMG. The G550 used a naturally-aspirated 5.5L V8 with 383 hp, while the G63 AMG used a hand-built twin turbo version of the same 5.5L V8 making 537 hp.

The top-of-the-line G65 AMG used a twin-turbo 6.0L V12 making a ridiculous 604 hp. They all use a 7-speed G-Tronic automatic transmission, tuned differently for each variation.

The Mercedes-Benz G-Class Service Guide recommends the following maintenance interval schedule for G550, G63, and G65:

Service A: Check all lights, warning lights and horn operation, change synthetic engine oil and filter, replace remote key battery, check cooling system strength and adjust level if necessary, check brake fluid level, check brake pad thickness (front and rear), inspect tire condition and set pressures, check wipers, washer jets and headlamp cleaning system.

Service B: includes everything in Service A in addition to: Inspect suspension system, inspect poly V belt, visual check for leaks on major components, check engine air filter and replace if necessary, check seatbelts and anchor system, check steering components, check driveline components, replace cabin air filter, check and correct headlamp settings, check bodywork for corrosion, rotate tires to promote even wear, clean water cowling to ensure proper drainage.

Brakes, Rotors, Pads, Fluid

The Mercedes-Benz G-Class is a big, heavy vehicle. It needs large brakes to bring it to a stop, especially in racy AMG trim.

Thankfully Mercedes-Benz engineers are some of the finest out there and have thought of this. The G550 is equipped with 314 mm brakes up front with 271 mm in the rear. Both the G63 and G65 AMG versions come with massive 375 mm brakes in the front with 330 mm in the rear.

Brake wear varies from vehicle to vehicle, driver to driver. There are many factors that contribute to brake wear, and therefore they must be inspected at least at every service interval to ensure the safety of the occupants. Brake fluid must be changed every 2 years or 25,000 miles, whichever comes first.

Tires, Suspension & Alignment

Tires are also wearable items that need to be checked at every service interval. Unfortunately, many owners tend to ignore their tires. As they are the only part of your vehicle that are in contact with the ground, they affect handling, acceleration, braking, and crucially, safety. Wear will vary depending on driving conditions, driving style, and whether or not the vehicle is all-wheel drive or not.

The Mercedes-Benz G-Class comes with these tire sizes:

Front P265/60/VR18
Rear P265/60/VR18

G63/G65 AMG
Front P275/50/VR20
Rear P275/50/VR20

Alignment can seriously affect both tire wear as well as the handling characteristics of a car. Therefore, it is imperative that the alignment is checked on a regular basis.

The Mercedes-Benz G-Class Guide recommends checking camber, castor, and toe for tolerances within factory specification, or a custom specification if deemed necessary.

The suspension’s job is to not only keep a comfortable ride; it is also to provide optimal handling characteristics. Properly functioning suspension will keep alignment within specification in a straight line as well as in the corners.

Moreover, this keeps the tires from wearing unevenly. At each service interval, it is recommended to check the suspension components for any squeaks, rattles, leakage, or play.