01
Mercedes-Benz OM605 Engine - Replacement Cost, Problems & CompatibilityProblems & Compatibility
The OM605 is Mercedes-Benz’s 2.5-litre inline-6 pre-chamber diesel, fitted to the W124 and W210 E-Class and the G-Class. Reconditioned OM605 engines typically start from £1,600 , and while request volumes are lower than modern diesels, it remains a highly sought-after unit for classic Mercedes saloon and off-road restorations.
Supply & Fit Available
12-Month Warranty
Nationwide Delivery
100+ Suppliers
Used from
£500
Reconditioned from
£1,600
Rebuilt from
£2,800
GB
Secure enquiry - no spam.
Quotes only from vetted UK engine specialists.
Key Specs
Mercedes-Benz OM605 - Specifications at a Glance
Engine Code
OM605 (including OM605.910, OM605.950, OM605.960)
Fuel
Diesel
Configuration
2.5L inline-6, SOHC, 12-valve, pre-chamber
Power Output(s)
83 kW (113 hp) - 110 kW (150 hp)
Years Produced
1993-1998
UK Models Fitted
3 Mercedes model families - full list in Compatibility below
Replaced
OM602
Replaced By
OM612 / OM613
Most Common Failure
High-mileage timing chain stretch and injector seal weeping
Reconditioned Price Range
£1,600-£2,600 supply-only
Vetted UK specialists for OM605 replacements
Minimum 12-month warranty on reconditioned and rebuilt options
Fitted To
Which Mercedes Models Use the OM605-
The OM605 was the definitive 6-cylinder diesel for Mercedes-Benz’s mid-size and off-road lineup throughout the mid-1990s, bridging the gap between the compact OM604 and the flagship OM606.
02
Mercedes-Benz E-Class
03
Mercedes-Benz G-Class
CROSS-BRAND
OM605 is documented across 3 BMW applications spanning E-Class, G-Class. Registration lookup confirms the exact suffix before quotes are sent.
Not sure which engine your car has?
Not sure which engine your car has- Enter your registration above - we'll confirm your exact OM605 fitment before any quotes are sent.
Prices
Mercedes-Benz OM605 Engine Replacement Cost (UK)
Condition | Supply Only | Fitted (Independent Specialist) | Typical Warranty |
|---|---|---|---|
Used | £500-£1,000 | £1,100-£1,900 | 3-6 months |
Reconditioned | £1,600-£2,600 | £2,400-£3,600 | 12-24 months |
Rebuilt | £2,800-£4,000 | £3,800-£5,200 | 12-24 months |
What genuinely moves the price for this engine is whether it is a naturally aspirated or turbocharged variant, and the condition of the mechanical injection pump. Because the OM605 is a 6-cylinder pre-chamber diesel, recon specialists often upgrade the glow plug system, vacuum pump, and injector seals as standard. For a full breakdown of market rates, see our full reconditioned engine cost guide.
Labour Guide
Fitting an OM605 engine typically takes 10-14 hours at £65-£85/hr (independent) - confirm exact labour when comparing quotes.
Price Factors
Ready to compare OM605 quotes?
Get competitive quotes from trusted UK specialists today.
Common Problems
Mercedes-Benz OM605 Engine Problems - What Actually Fails
Every engine has its weak points. Here are the known issues with the OM605, based on real-world data and verified failure patterns.
Verified issue focus: High-mileage timing chain stretch and injector seal weeping.
1. Timing Chain Stretch and Guide Wear - All variants
1. Timing Chain Stretch and Guide Wear - All variants
Typical onset:
150,000+ miles
What happens:
The timing chain and plastic guide rails can stretch and wear over high mileage, leading to a distinct rattling noise on cold starts. If ignored, the chain can jump a tooth, causing valve-to-piston contact and catastrophic engine failure.
Repair vs replace:
If caught early, a timing chain and guide kit replacement is straightforward and cost-effective. If the engine has already suffered valve damage, a full reconditioned unit is the only viable path.
Read more about this issue
2. Injector Seal Weeping ("Black Death") - All variants
2. Injector Seal Weeping ("Black Death") - All variants
Typical onset:
100,000+ miles
What happens:
The copper washer seals at the base of the injectors degrade over time, allowing combustion gases to escape. This creates a black, crusty carbon buildup around the injector heads and can lead to difficult cold starts or rough idling.
Repair vs replace:
This is a routine maintenance item, not a terminal failure. Replacing the seals and cleaning the cylinder head is inexpensive and should be done preventatively.
Read more about this issue
3. Glow Plug and Pre-chamber Issues - High-mileage units
3. Glow Plug and Pre-chamber Issues - High-mileage units
Typical onset:
120,000+ miles
What happens:
As a pre-chamber diesel, the OM605 relies heavily on the glow plug system for cold starts. Failed glow plugs can lead to extended cranking, which in turn can cause the pre-chambers to crack or the glow plugs to seize in the cylinder head.
Repair vs replace:
Glow plug replacement is routine, but if a plug has seized and broken off in the head, cylinder head removal or replacement is often required.
Read more about this issue
The OM605 is widely regarded as one of Mercedes’ most robust inline-6 diesels, offering a significant refinement step up from the 5-cylinder OM602 it replaced. Units maintained with regular oil changes and preventative injector seal replacements routinely exceed 300,000 miles without major internal issues .
Compare rebuilt OM605 engine prices with the failure already addressed
Engine Variants
OM605 Sub-Codes Explained - Which One Is in Your Car-
INTRO: The OM605 family shares the same fundamental 2.5L inline-6 block and pre-chamber head design, but forced induction and tuning vary depending on the chassis. Identifying your exact sub-code ensures you order the correct injection pump, turbo, and ancillary components. - Fitted to: E-Class W124 (E 250 D), E-Class W210 (E 250 D) - Key technical difference: The base naturally aspirated variant, featuring a simpler ancillary layout without turbo plumbing and a mechanical injection pump calibrated for lower output. - Sub-code-specific failure note: Shares the family failure pattern above; no unique widespread defects beyond standard high-mileage wear. - Interchange note: Not a straight swap with the .960 turbo variants; the injection pump, exhaust manifold, and oil return lines differ significantly. - Fitted to: Select export W124/W210 models and specific commercial applications - Key technical difference: Functionally identical to the .910 in core architecture, but calibrated for specific regional emission standards or fitted with different ancillary brackets (e.g., alternator or vacuum pump orientation). - Sub-code-specific failure note: Shares the family failure pattern above. - Interchange note: Directly interchangeable with the OM605.910 in most applications, provided the injection pump and ancillary brackets are swapped to match the original chassis specification. - Fitted to: E-Class W124 (E 250 TD), E-Class W210 (E 250 TD), G-Class W463 (G 250 TD) - Key technical difference: Adds a turbocharger and intercooler to the 2.5L block, requiring a higher-capacity mechanical injection pump, revised piston cooling jets, and an upgraded cooling system to handle the additional heat. - Sub-code-specific failure note: Shares the family failure pattern above; turbocharger shaft wear and vacuum pump leaks are the primary additional wear items. - Interchange note: Can be swapped with the .910/.950 block, but requires the complete turbo kit, different injection pump, and revised engine management linkages.
The engine code is stamped on the right-hand side of the cylinder block, just above the oil filter housing. It will also be listed on your V5C logbook under "Engine Capacity" or visible via a VIN decode. Not sure- Enter your registration above for instant confirmation.
Easily Confused
OM602
the 2.5L inline-5 pre-chamber diesel that the OM605 evolved from, sharing the same robust mechanical injection principles but with a slightly smaller displacement.
Alternative / Next-Gen Code
OM612
the modern common-rail CDI successor that eventually replaced the OM605 family, featuring electronic injection for significantly higher output, efficiency, and emissions compliance.
Related JLR Variants
OM604
the inline-4 variant that shares the same pre-chamber diesel philosophy, timing chain layout, and mechanical injection principles, but in a smaller 2.0L-2.2L displacement configuration for compact chassis.
Confirm the exact OM605 fitment
The engine code is stamped on the right-hand side of the cylinder block, just above the oil filter housing. It will also be listed on your V5C logbook under "Engine Capacity" or visible via a VIN decode. Not sure- Enter your registration above for instant confirmation.
Buying Guide
Buying a Replacement OM605 Engine - What to Choose
Choosing the right replacement route depends on your budget, risk tolerance, and ownership goals. Here's a breakdown of your options.
Used:
A used OM605 engine makes sense only if it comes with verifiable service history and a recent timing chain guide inspection. Given the age of these vehicles, the primary risk is hidden corrosion or degraded rubber seals, so a compression test is mandatory before purchase.
Reconditioned:
A proper reconditioned OM605 engine is the sweet spot for most buyers. A reputable rebuild will address the common failure points by fitting a new timing chain guide kit, updated injector seals, and a refreshed mechanical injection pump, giving the engine a fresh lease on life.
Rebuilt:
A full OM605 engine rebuild is justified for high-mileage G-Class applications or classic W124/W210 restorations where originality and maximum longevity are required. An upgraded rebuild should include line-boring the block, new pistons/rings, and a balanced crankshaft.
Supply & Fit Line:
Sourcing and fitting through our vetted network ensures your OM605 engine is installed by specialists familiar with classic Mercedes mechanical diesels, backed by a nationwide warranty.
Vehicle Value Note:
Because the OM605 is typically found in vehicles valued between £1,500 and £8,000 for standard examples (though classic low-mileage W124 and G-Class models can command much higher premiums), a full replacement can represent a significant portion of the car's worth. If the lowest viable replacement cost exceeds approximately 60% of the vehicle's current market value, evaluate scrap value before committing .
Compare OM605 Engine Prices Now
Related Engines
Engines Related to the Mercedes-Benz OM605
Explore engines that are closely related to the Mercedes-Benz OM605, including its predecessor, successor, and key family variants.
Predecessor
OM602
the 2.5L inline-5 pre-chamber diesel that the OM605 evolved from, sharing the same robust mechanical injection principles but with a slightly smaller displacement.
Successor
OM612
the modern common-rail CDI successor that eventually replaced the OM605 family, featuring electronic injection for significantly higher output, efficiency, and emissions compliance.
Sibling
OM604
the inline-4 variant that shares the same pre-chamber diesel philosophy, timing chain layout, and mechanical injection principles, but in a smaller 2.0L-2.2L displacement configuration for compact chassis.
Sibling
OM606
the inline-6 variant that shares the same pre-chamber diesel philosophy, but in a larger 3.0L displacement configuration for heavier chassis applications.
FAQ
Mercedes-Benz OM605Frequently Asked Questions
Question 1How much does a Mercedes OM605 engine replacement cost-
A reconditioned Mercedes OM605 engine typically costs between £1,600 and £2,600 for supply only . Fitted costs generally range from £2,400 to £3,600 depending on the specialist, while used units can be found from £500 but carry higher risk due to the engine's age. Compare OM605 engine replacement quotes today
Compare OM605 quotesQuestion 2What is the most common failure on the OM605 engine-
The most documented issues are timing chain stretch and guide wear, alongside injector seal weeping and glow plug failures. Timing chain rattle on cold starts is the primary warning sign of guide degradation, which can lead to catastrophic valve damage if ignored, whereas injector seal failure causes black carbon buildup around the injector heads but is a cheap and routine fix. Get quotes for a rebuilt OM605 with these issues resolved
Compare OM605 quotesQuestion 3Which Mercedes models use the OM605 engine-
The OM605 was fitted to the W124 E-Class (E 250 D, E 250 TD), the W210 E-Class (E 250 D, E 250 TD), and the W463 G-Class (G 250 TD), serving as the definitive 6-cylinder diesel for these mid-size and off-road chassis throughout the mid-1990s. Check your registration to confirm your exact OM605 fitment
Compare OM605 quotesQuestion 4Should I buy a used or reconditioned OM605 engine-
A reconditioned OM605 is strongly recommended over a used unit due to the age of these vehicles. A proper rebuild will replace the timing chain, plastic guide rails, tensioner, and injector seals, eliminating the most common failure points, whereas used engines may appear cheaper upfront but often hide stretched chains that will fail shortly after installation. Compare reconditioned OM605 engine prices from UK specialists
Compare OM605 quotesQuestion 5What is the difference between OM605.910, .950, and .960-
The OM605.910 is the 2.5L naturally aspirated variant, the OM605.950 is a 2.5L naturally aspirated version calibrated for specific export or commercial applications, and the OM605.960 is the 2.5L turbocharged version. The .960 requires a higher-capacity mechanical injection pump, revised piston cooling jets, and an upgraded cooling system to handle the additional heat and cylinder pressures. Enter your reg above to identify your exact OM605 sub-code ═══════════════════════════════════════
Compare OM605 quotesCompare Mercedes-Benz OM605 Engine Prices Today
Vetted UK specialists who work on classic Mercedes mechanical diesels like the OM605 every week Minimum 12-month warranty on every reconditioned and rebuilt OM605 engine Nationwide delivery - supply-only or full supply & fit available across the UK Get a free, no-obligation comparison of OM605 engine prices tailored to your exact sub-code. Our registration lookup confirms your fitment before any quotes are sent, ensuring you receive the correct unit with matching ancillary components. With reconditioned OM605 engines starting from an estimated £1,600, comparing takes two minutes and could save you hundreds on labour and unexpected parts.
Vetted UK Specialists
Vetted UK specialists for OM605 replacements
Minimum 12-Month Warranty
Minimum 12-month warranty on reconditioned and rebuilt options
Nationwide Delivery
Nationwide delivery plus supply and fit availability
Expert Support
Secure enquiry - no spam. Quotes only from vetted UK engine specialists.
Secure enquiry - no spam. Quotes only from vetted UK engine specialists.
Get Free OM605 Engine Quotes