According to Au7o's analysis of 1,510+ owner reports, the 2005 Mercedes-Benz G-Class has 5 documented known issues, with 1 rated critical. The most serious is Front Axle Seal Leak ($600-$1,500 repair). The most commonly reported issue is Steering Damper Wear Causing Wander and Vibration with 890 owner reports. Across all issues with published estimates, repair costs range from $200 to $8,000. DIY maintenance guides at au7o.io.
On the 2000-2018 Mercedes-Benz G-Class, the front differential axle seals on the W463 G-Class are prone to leaking gear oil, particularly on higher-mileage vehicles. Oil seeps past the worn seals onto the brake components, potentially contaminating brake pads and reducing braking effectiveness. The solid axle design makes seal replacement more involved than on IFS vehicles.
Replace both front axle seals and inspect the axle shafts for scoring. If brake pads are contaminated with oil, replace pads and resurface or replace rotors. Use genuine Mercedes seals for proper fitment on the solid axle housing.
Owner tips & cautions
WarningDo not ignore front axle seal leaks — oil contamination of brake pads is a serious safety issue. Replace both sides even if only one is leaking, as the other will follow soon.
Medium Confidence620 owner reportsLast reported by owners Nov 2025Reviewed Mar 2026
On the 2000-2018 Mercedes-Benz G-Class OM642 3.0L V6 Diesel, european-market diesel G-Class models with the OM642 3.0L V6 (G 320 CDI / G 350 CDI / G 350 d) commonly develop oil leaks from the engine oil cooler seals seated in the valley of the engine block. The original orange seals harden from heat and shrink, allowing oil to weep down the back of the block. Mercedes upgraded to purple Viton seals (~2010+), which reduced but did not eliminate the problem. Because the cooler sits under the intake, the leak is often misdiagnosed and the repair is labor-intensive.
Replace the oil cooler O-ring/gasket seals (use the updated Viton seals) and inspect the cooler itself for damage. While the intake is removed, it is cost-effective to also service the swirl-flap linkage and clean the EGR. Confirm the leak source versus turbo pedestal and valve cover gaskets, which can leak simultaneously.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
Genuine Mercedes-Benz OM642 oil-cooler-to-block seal 6421880580, quantity two
OEMMercedes-Benz A6421880580 / 642-188-05-80
Pair of updated cooler seals after the OM642 valley leak is positively traced to both cooler-to-block joints Fitment/availability: The inspected direct U.S. genuine-parts page identifies 642-188-05-80 as the elastomer-molded oil-cooler s…
On the 2005-2018 Mercedes-Benz G-Class OM642 3.0L V6 Diesel, on diesel G-Class models with the OM642 V6, the plastic intake-manifold swirl flap linkage becomes brittle and snaps, and the swirl-flap actuator motor can fail (often after being contaminated by oil weeping from the turbo inlet seal). The broken plastic rods can also be drawn into the engine in worst cases. This is a well-known weak point that triggers intake-runner control faults, limp mode, and emissions test failures. Particularly relevant to higher-mileage EU diesel examples.
Replace the swirl-flap actuator and fit a metal/upgraded swirl-flap repair kit (e.g. updated connecting rod kit) to replace the brittle plastic linkage. Address any upstream turbo oil leak contaminating the motor. A resistor bypass only clears the code and is not a proper repair if the linkage is broken.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
External linkage-only branch when both OM642 manifold flap shafts and actuator test good Fitment/availability: The inspected manufacturer listing identifies X8R0175 as two aluminum rods with six retaining clips and anti-friction adapters…
Later G 350 actuator-motor branch after commanded tests prove motor/circuit failure and VIN/stamped number match Fitment/availability: The inspected official German genuine-parts page identifies A6421500594 as an in-stock actuator at €26…
On the 2000-2018 Mercedes-Benz G-Class, the recirculating ball steering system on W463 G-Class models relies on a steering damper that wears out over time, causing excessive highway wander, steering wheel vibration at speed, and a vague on-center feel. The solid front axle design amplifies these symptoms compared to independent suspension vehicles.
Replace the steering damper with an OEM or upgraded aftermarket unit such as Bilstein B6. Inspect the drag link and tie rod ends for play simultaneously. Perform a front-end alignment after replacement.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
Confirmed failed steering-damper branch for covered 2002-2018 W463 applications Fitment/availability: The inspected official direct product page identifies front steering damper 463-463-01-32-64, replacing 4634630032/4634630132, for cata…
High Confidence890 owner reportsLast reported by owners Dec 2025Reviewed Mar 2026
On the 2000-2018 Mercedes-Benz G-Class, the hand-built W463 body (Magna Steyr, Graz) is widely documented for rust because the panel metallurgy and rust-proofing are little changed from the late-1970s design. Common corrosion sites are the rear tailgate (especially the lower section around the spare-tire mount), door bottoms, sills/rocker areas, window/windscreen weatherstrip channels that trap water, and the rear frame tubes and rear strut/shock mounts on the ladder chassis. Frame-tube and strut-mount corrosion is a structural safety concern on older/salt-belt examples, distinct from the cosmetic body rust.
Common Symptoms
Paint bubbling on tailgate/doors
Visible rust on sills and door bottoms
Orange-brown discoloration on frame
Creaking/clunking from rear suspension
Flaking underbody coating
How to Fix
Inspect the tailgate lower edge, door bottoms, sills, and especially the rear frame tubes and strut mounts; sandblast and treat or weld in repair panels before rust spreads. Preventatively apply cavity wax (Waxoyl) inside doors and underbody, wash off road salt after winter, and keep trim-clip and weatherstrip drainage clear. Severe frame corrosion may require frame section repair rather than full-frame replacement.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
Waxoyl Power Shield cavity-protection aerosol 500 mL
OEMWaxoyl / Rovers North RNW5004PF
Accessible closed-cavity prevention branch after corrosion repair, cleaning/drying and drain verification Fitment/availability: The inspected U.S. retailer category identifies Waxoyl Power Shield For Cavities 500 mL aerosol, model RNW500…
Waxoyl Black Hardwax Plus underbody protection 5 L
OEMWaxoyl W5005P / Rovers North RNW5005P
Underbody corrosion-protection branch after structural repair and compatible surface preparation Fitment/availability: The inspected direct U.S. product page identifies item RNW5005P/W5005P as a 5-liter Hardwax Plus underbody coating, re…
What are the most common Mercedes-Benz G-Class problems?
According to Au7o's analysis of 1,510+ owner reports, the 2005 Mercedes-Benz G-Class has 5 documented issues. The most frequently reported are: Front Axle Seal Leak, Steering Damper Wear Causing Wander and Vibration, Body, Tailgate and Underbody Frame Corrosion. Of these, 1 is rated critical and should be addressed promptly.
Is the Mercedes-Benz G-Class reliable?
The 2005 Mercedes-Benz G-Class has 5 known issues documented across 1,510+ owner reports. 1 issue is rated critical: Front Axle Seal Leak. Prospective buyers should inspect for these issues and factor potential repair costs into their purchase decision. Regular maintenance following the manufacturer's schedule helps prevent many common problems.
How much does it cost to fix common Mercedes-Benz G-Class problems?
Repair costs for known Mercedes-Benz G-Class issues range from $200 to $8,000, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, Front Axle Seal Leak, typically costs $600-$1,500 to repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.
What is the 2000-2018 Mercedes-Benz G-Class Front Axle Seal Leak?
The front differential axle seals on the W463 G-Class are prone to leaking gear oil, particularly on higher-mileage vehicles. Oil seeps past the worn seals onto the brake components, potentially contaminating brake pads and reducing braking effectiveness. The solid axle design ma… Repairs typically run $600-$1,500. Severity: high.
What is the 2000-2018 Mercedes-Benz G-Class Steering Damper Wear Causing Wander and Vibration?
The recirculating ball steering system on W463 G-Class models relies on a steering damper that wears out over time, causing excessive highway wander, steering wheel vibration at speed, and a vague on-center feel. The solid front axle design amplifies these symptoms compared to in… Repairs typically run $300-$800. Severity: medium.
What is the 2000-2018 Mercedes-Benz G-Class Body, Tailgate and Underbody Frame Corrosion?
The hand-built W463 body (Magna Steyr, Graz) is widely documented for rust because the panel metallurgy and rust-proofing are little changed from the late-1970s design. Common corrosion sites are the rear tailgate (especially the lower section around the spare-tire mount), door b… Repairs typically run $400-$8,000. Severity: medium.
What is the 2000-2018 Mercedes-Benz G-Class OM642 3.0L V6 Diesel Oil Cooler Seal Leak (G 350 CDI / G 350 d)?
European-market diesel G-Class models with the OM642 3.0L V6 (G 320 CDI / G 350 CDI / G 350 d) commonly develop oil leaks from the engine oil cooler seals seated in the valley of the engine block. The original orange seals harden from heat and shrink, allowing oil to weep down th… Repairs typically run $600-$1,800. Severity: medium.
What is the 2005-2018 Mercedes-Benz G-Class OM642 Diesel Intake Manifold Swirl Flap (Runner) Failure?
On diesel G-Class models with the OM642 V6, the plastic intake-manifold swirl flap linkage becomes brittle and snaps, and the swirl-flap actuator motor can fail (often after being contaminated by oil weeping from the turbo inlet seal). The broken plastic rods can also be drawn in… Repairs typically run $200-$900. Severity: medium.
Content on this page was compiled with AI assistance using NHTSA complaints, TSBs, owner reports, and public automotive data. While we strive for accuracy, this information may contain errors. Always verify repair procedures and specifications with your vehicle's service manual or a qualified mechanic.
