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Mercedes-Benz OM604 Engine - Replacement Cost, Problems & CompatibilityProblems & Compatibility
The OM604 is Mercedes-Benz’s 2.0-litre and 2.2-litre inline-4 pre-chamber diesel, fitted to the W202 C-Class and W210 E-Class. Reconditioned OM604 engines typically start from £1,300 , and while request volumes are lower than modern diesels, it remains a staple for classic Mercedes saloon restorations and daily-driven W210 estates.
Supply & Fit Available
12-Month Warranty
Nationwide Delivery
100+ Suppliers
Used from
£400
Reconditioned from
£1,300
Rebuilt from
£2,200
GB
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Key Specs
Mercedes-Benz OM604 - Specifications at a Glance
Engine Code
OM604 (including OM604.910, OM604.950, OM604.960)
Fuel
Diesel
Configuration
2.0L-2.2L inline-4, SOHC, 8-valve, pre-chamber
Power Output(s)
55 kW (75 hp) - 65 kW (88 hp)
Years Produced
1993-1998
UK Models Fitted
2 Mercedes model families - full list in Compatibility below
Replaced
OM601 / OM615
Replaced By
OM611
Most Common Failure
High-mileage timing chain guide wear and injector seal weeping
Reconditioned Price Range
£1,300-£2,200 supply-only
Vetted UK specialists for OM604 replacements
Minimum 12-month warranty on reconditioned and rebuilt options
Fitted To
Which Mercedes Models Use the OM604-
The OM604 was the definitive 4-cylinder diesel for Mercedes-Benz throughout the mid-1990s, powering the entry-level W202 C-Class and W210 E-Class saloons and estates before the introduction of the CDI common-rail era.
02
Mercedes-Benz E-Class
CROSS-BRAND
OM604 is documented across 2 BMW applications spanning C-Class, E-Class. Registration lookup confirms the exact suffix before quotes are sent.
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Not sure which engine your car has- Enter your registration above - we'll confirm your exact OM604 fitment before any quotes are sent.
Prices
Mercedes-Benz OM604 Engine Replacement Cost (UK)
Condition | Supply Only | Fitted (Independent Specialist) | Typical Warranty |
|---|---|---|---|
Used | £400-£900 | £900-£1,600 | 3-6 months |
Reconditioned | £1,300-£2,200 | £1,900-£3,000 | 12-24 months |
Rebuilt | £2,200-£3,500 | £3,000-£4,500 | 12-24 months |
What genuinely moves the price for this engine is the condition of the mechanical injection pump and whether the timing chain guides have been proactively replaced. Because the OM604 is a pre-chamber diesel, recon specialists often upgrade the glow plug system and injector seals as standard. For a full breakdown of market rates, see our full reconditioned engine cost guide.
Labour Guide
Fitting an OM604 engine typically takes 8-12 hours at £65-£85/hr (independent) - confirm exact labour when comparing quotes.
Price Factors
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Common Problems
Mercedes-Benz OM604 Engine Problems - What Actually Fails
Every engine has its weak points. Here are the known issues with the OM604, based on real-world data and verified failure patterns.
Verified issue focus: High-mileage timing chain guide wear and injector seal weeping.
1. Timing Chain Guide and Tensioner Wear - All variants
1. Timing Chain Guide and Tensioner Wear - All variants
Typical onset:
150,000+ miles
What happens:
The duplex timing chain itself is robust, but the plastic guide rails and hydraulic tensioner can wear or fail over high mileage, leading to a distinct rattling noise on cold starts. If ignored, the chain can slap or 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
The OM604 is widely regarded as one of the most robust 4-cylinder diesels Mercedes ever built, transitioning from the older OM601 architecture with improved refinement. Units maintained with regular oil changes routinely exceed 300,000 miles without major internal issues .
Compare rebuilt OM604 engine prices with the failure already addressed
Engine Variants
OM604 Sub-Codes Explained - Which One Is in Your Car-
INTRO: The OM604 family shares the same fundamental pre-chamber block and head design, but displacement and calibration vary depending on the chassis. Identifying your exact sub-code ensures you order the correct injection pump and ancillary components. - Fitted to: C-Class W202 (C 200 D), E-Class W210 (E 200 D) - Key technical difference: The smallest displacement variant, featuring a specific 2.0L crankshaft and mechanical injection pump calibrated for lower output. - Sub-code-specific failure note: Shares the family failure pattern above; no unique widespread defects. - Interchange note: Not a straight swap with the 2.2L variants; the engine mounts, injection pump, and wiring loom differ significantly. - Fitted to: C-Class W202 (C 220 D), E-Class W210 (E 220 D) - Key technical difference: Increased stroke to 2.2L (2155 cc) for higher low-end torque, making it the preferred choice for the heavier W210 E-Class chassis. - Sub-code-specific failure note: Shares the family failure pattern above. - Interchange note: The passenger car versions share the same core block, but the sump, oil pickup, and accessory brackets are application-specific between the W202 and W210. - Fitted to: Select export W210 models and specific commercial applications - Key technical difference: Functionally identical to the .950 in core architecture, but calibrated for specific regional emission standards or heavier gross weights. - Sub-code-specific failure note: Shares the family failure pattern above. - Interchange note: Directly interchangeable with the OM604.950 in most applications, provided the injection pump is swapped to match the original calibration.
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
OM601
the foundational 4-cylinder pre-chamber diesel that the OM604 evolved from, sharing the same robust mechanical injection principles but with a slightly less refined block design.
Alternative / Next-Gen Code
OM611
the modern common-rail CDI successor that eventually replaced the OM604 family, featuring turbocharging and electronic injection for significantly higher output, efficiency, and emissions compliance.
Related JLR Variants
OM603
the inline-6 variant that shares the same pre-chamber diesel philosophy, timing chain layout, and mechanical injection principles, but in a larger 3.0L displacement configuration for heavier chassis applications.
Confirm the exact OM604 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 OM604 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 OM604 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 OM604 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 OM604 engine rebuild is justified for high-mileage W210 estates or classic W202 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 OM604 engine is installed by specialists familiar with classic Mercedes mechanical diesels, backed by a nationwide warranty.
Vehicle Value Note:
Because the OM604 is typically found in W202 and W210 vehicles valued between £1,000 and £5,000, 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 .
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Related Engines
Engines Related to the Mercedes-Benz OM604
Explore engines that are closely related to the Mercedes-Benz OM604, including its predecessor, successor, and key family variants.
Predecessor
OM601
the foundational 4-cylinder pre-chamber diesel that the OM604 evolved from, sharing the same robust mechanical injection principles but with a slightly less refined block design.
Successor
OM611
the modern common-rail CDI successor that eventually replaced the OM604 family, featuring turbocharging and electronic injection for significantly higher output, efficiency, and emissions compliance.
Sibling
OM603
the inline-6 variant that shares the same pre-chamber diesel philosophy, timing chain layout, and mechanical injection principles, but in a larger 3.0L displacement configuration for heavier chassis applications.
FAQ
Mercedes-Benz OM604Frequently Asked Questions
Question 1How much does a Mercedes OM604 engine replacement cost-
A reconditioned Mercedes OM604 engine typically costs between £1,300 and £2,200 for supply only . Fitted costs generally range from £1,900 to £3,000 depending on the specialist, while used units can be found from £400 but carry higher risk due to the engine's age. Compare OM604 engine replacement quotes today
Compare OM604 quotesQuestion 2What is the most common failure on the OM604 engine-
The most documented issues are timing chain guide and tensioner wear, alongside injector seal weeping. 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 OM604 with these issues resolved
Compare OM604 quotesQuestion 3Which Mercedes models use the OM604 engine-
The OM604 was fitted to the W202 C-Class (C 200 D, C 220 D) and the W210 E-Class (E 200 D, E 220 D), serving as the definitive 4-cylinder diesel for these compact and mid-size saloons and estates throughout the mid-to-late 1990s. Check your registration to confirm your exact OM604 fitment
Compare OM604 quotesQuestion 4Should I buy a used or reconditioned OM604 engine-
A reconditioned OM604 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 two most common failure points, whereas used engines may appear cheaper upfront but often hide stretched chains that will fail shortly after installation. Compare reconditioned OM604 engine prices from UK specialists
Compare OM604 quotesQuestion 5What is the difference between OM604.910, .950, and .960-
The OM604.910 is the 2.0L naturally aspirated variant, the OM604.950 is the 2.2L naturally aspirated version with a longer stroke for higher low-end torque, and the OM604.960 is a 2.2L variant calibrated for specific export or commercial applications; they share the same core block, but the injection pumps, sumps, and accessory brackets are not always directly interchangeable without modification. Enter your reg above to identify your exact OM604 sub-code ═══════════════════════════════════════
Compare OM604 quotesCompare Mercedes-Benz OM604 Engine Prices Today
Vetted UK specialists who work on classic Mercedes mechanical diesels like the OM604 every week Minimum 12-month warranty on every reconditioned and rebuilt OM604 engine Nationwide delivery - supply-only or full supply & fit available across the UK Get a free, no-obligation comparison of OM604 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 OM604 engines starting from an estimated £1,300, comparing takes two minutes and could save you hundreds on labour and unexpected parts.
Vetted UK Specialists
Vetted UK specialists for OM604 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
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