Car got a check engine for failed turbochargers at 71000 miles. Mercedes refused to acknowledge and get the problem addressed.
2014 Mercedes-Benz GL-Class engine problems
moderate 10 complaints filed with NHTSA · avg repair $3,100 · see engine across all vehicles →
Complaints
10
Recalls
0
Avg fix
$3,100
When does it fail?
Of the 10 engine complaints filed for the 2014 Mercedes-Benz GL-Class, here's the actual mileage breakdown — failures cluster heaviest at 100,000-125,000 mi.
0-25k
25-50k
50-75k
75-100k
100-125k
125-150k
150k+
Each bar shows the share of total complaints filed at that mileage range. Peak failure window highlighted. Some owners report problems earlier; some make it well past 150,000 miles symptom-free. Maintenance habits and driving conditions shift the curve as much as mileage alone.
What stands out
Of the 8 model years of Mercedes-Benz GL-Class we track for engine problems, this one carries the most owner complaints on file — 10.
Engine accounts for 26% of all owner complaints filed against this vehicle, across 4 categories tracked.
The failure pattern owners describe
Buyer takeaway: A 2014 Mercedes-Benz GL-Class engine carries substantial risk: owners report timing chain failure as early as 63,000 miles ($15,000–$75,000 repair), oil leaks across multiple seals, exhaust valve leakage, and complete engine failure requiring replacement. Multiple defects emerge before 110,000 miles, and Mercedes has excluded these models from related recalls.
The 2014 GL-Class engines show a pattern of early, costly failures across multiple subsystems. Timing chain noise and rattling appear as early as 63,000 miles—far below the typical 200,000+ mile threshold dealers claim—with quoted repairs reaching $75,000. One owner's dealer reportedly laughed off the concern before confirming the defect.
Oil leaks plague multiple components: valve cover gaskets, oil cooler seals, and front timing covers. Owners report burning smells and progressive oil loss. Mercedes announced a 2023 recall for engine oil leaks but excluded the 2014 model year despite identical complaints.
Engine failures requiring full replacement occur at 108,000 miles with unexplained stalling at highway speed. Exhaust valve leakage triggers check engine lights at 104,000 miles; Mercedes cites TSB 10233794 as non-applicable. One turbocharger failure at 71,000 miles resulted in a warranty denial. A borescope inspection uncovered scored cylinder walls, prompting litigation (Lena Jamil, et al. v. Mercedes-Benz USA, LLC).
Across these failures, diagnosis often proves difficult—some noise persists without diagnostic codes—and owners report dealer reluctance to disclose root causes before recommending engine replacement. No owner in these narratives completed repairs, raising questions about total cost exposure and whether coverage remained available.
Failure modes owners describe
Valve Cover Oil Leaks
Oil seeping from valve cover gaskets, often requiring resealing of front timing covers. Owners report a burning smell and progressive oil loss. One complaint at 50K miles notes Mercedes issued a 2023 recall that excluded many older GL models despite the same defect.
When: 50,000 miles or earlier; intermittent across production
Symptoms owners cite: Burning smell from engine; Oil visible underneath vehicle; Progressive oil loss over time
Repairs/costs cited: Valve cover reseal/replacement with silicone sealant application; owners cite dealer quotes but specific costs not stated in narratives
Recalls/TSBs owners mention: 2023 recall announced but excludes 2014 GL-Class models with same reported defect
Timing Chain Failure
Premature timing chain wear and noise at unusually low mileage (63K–70K miles), contrary to dealer claims this only occurs at 200K+ miles. One 2014 GL350 owner reports quoted repair of $75,000; another cites dealer quote of $15,000. Online forums indicate this is a known issue specific to 2014 GL350 diesel models.
When: 63,000–70,000 miles
Symptoms owners cite: Rattling noise when starting, worse when cold; Excessive engine noise while idling and driving; Engine overheating and high fan speed; Noise persists until engine shut off
Repairs/costs cited: Timing chain replacement; quoted $15,000–$75,000 depending on model/severity
Recalls/TSBs owners mention: Dealers confirm defect but treat as design limitation; no recalls or TSBs cited by owners
Oil Cooler Seal Failure
Oil cooler seals fail, allowing oil to leak from under the vehicle. Check engine light illuminates. One 2014 GL350 owner had seals replaced at an independent mechanic; failure noted at 140,000 miles.
When: 140,000 miles
Symptoms owners cite: Oil leaking underneath vehicle; Check engine warning light illuminated
Repairs/costs cited: Oil cooler seals replacement performed at independent mechanic; owner did not disclose cost
Exhaust Valve Leakage
Exhaust valves develop internal leakage, triggering check engine light. Two independent assessments (dealer and independent mechanic) confirmed the defect. Manufacturer cited TSB 10233794 as non-applicable, offering no remedy.
When: 104,000 miles
Symptoms owners cite: Check engine warning light illuminated; Leaky exhaust valves (dealer diagnosis)
Repairs/costs cited: Exhaust valve replacement required; owner did not pursue repair or obtain cost estimate
Recalls/TSBs owners mention: TSB 10233794 does not apply; manufacturer referred owner to NHTSA Hotline
Engine Stalling / Total Engine Failure
Engine stalls at highway speed (65 MPH) with check engine light. Two separate shops (dealer and independent mechanic) diagnosed the failure as requiring complete engine replacement. One 2014 GL450 owner at 108K miles; another 2014 GL450 owner at similar mileage. Root cause of stall not disclosed in narratives.
When: 108,000 miles
Symptoms owners cite: Engine stalling while driving at highway speed; Check engine warning light illuminated
Repairs/costs cited: Engine replacement required; owner did not complete repair or obtain cost
Recalls/TSBs owners mention: Manufacturer notified and opened a case; no resolution provided
Scored Cylinder Walls
Engine develops scored cylinder walls, identified via borescope inspection. Requires full engine replacement. One complaint references litigation (Lena Jamil, et al. v. Mercedes-Benz USA, LLC, Case No: 2:22-cv-08130-FLA-AFM).
When: Not specified in narrative
Symptoms owners cite: Tapping noise in engine; Scored cylinder walls (borescope diagnosis)
Repairs/costs cited: Engine replacement required; subject of litigation case 2:22-cv-08130-FLA-AFM
Turbocharger Failure
Turbocharger fails early, generating check engine code. Manufacturer refuses to acknowledge or address the defect under warranty.
When: 71,000 miles
Symptoms owners cite: Check engine warning light for failed turbocharger
Repairs/costs cited: Turbocharger replacement needed; owner did not disclose cost
Recalls/TSBs owners mention: Manufacturer refused to acknowledge defect or provide warranty coverage
Synthesized from 10 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 5 most recent
The contact owns a 2014 Mercedes-Benz GL550. The contact stated that the check engine warning light was illuminated. The vehicle was taken to the dealer, where it was diagnosed with leaky exhaust valves. The dealer determined that the exhaust valves needed to be replaced. The vehicle was taken to an independent mechanic, where a similar assessment was made. The vehicle was not repaired. The…
Leaky exhaust valves
Tapping noise developed in the engine, after dealership inspection using borescope, scored cylinder walls were found, resulting to engine replacement. Please see: Lena Jamil, et al. v. Mercedes-Benz USA, LLC (Case No: 2:22-cv-08130-FLA-AFM)
The contact owns a 2014 Mercedes-Benz GL350. The contact stated that while inspecting the vehicle, there was oil leaking underneath the vehicle. Additionally, the check engine warning light was illuminated while operating the vehicle. The vehicle was taken to the local mechanic who diagnosed the vehicle and determined that the oil cooler seals were faulty and needed to be replaced. The seals were…
Had engine trouble with your 2014 Mercedes-Benz GL-Class?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the engine problem on the 2014 Mercedes-Benz GL-Class?
It's a documented issue but not catastrophic. 10 complaints have been filed. Repairs average $3,100 and most owners catch it before it causes a breakdown.
At what mileage does the engine typically fail?
Based on the 10 complaints filed, engine issues most often appear around 103,000 miles. Some report problems earlier; some make it well past 150,000 with no symptoms. Maintenance habits matter — vehicles that received timely fluid services and were not regularly overworked tend to last longer.
What does it cost to fix?
Independent shops typically charge around $3,100 for engine repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to engine?
No active recalls currently cover engine issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2014/Mercedes-Benz/GL-Class.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.