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Mercedes OM651 injector repair
Misfires, rough idle and hard starting on a Mercedes 2.1 CDI often come down to the injectors. We test each one and replace only what has failed — call or book a check.
Why book with us
Mercedes OM651 injector repair with clear advice.
The OM651 is the 2.1-litre four-cylinder diesel badged 200 CDI, 220 CDI and 250 CDI (later 200d, 220d, 250d) in the C-Class, E-Class, GLK, Vito and Sprinter from 2008 onward. Early versions of this engine were fitted with Delphi injectors that gained a reputation for failure, and many were changed under manufacturer campaigns. Injector faults remain one of the most common problems we diagnose on these engines.
A failing injector can cause misfires, a rough or knocking idle, hard starting when warm or cold, smoke, a strong diesel smell and the engine warning light. In some cases the car goes into limp mode. Injector seal leaks, where combustion gas escapes past the injector into the cylinder head, can cause a ticking noise and a black tar-like build-up around the injector.
An injector stuck open or leaking can wash oil off the cylinder wall, damage a piston and dilute the engine oil with diesel. Left long enough, that can turn an injector job into engine damage. A leaking seal ignored for too long can also make the injector very difficult to remove, which adds labour to the job.
We use Mercedes-capable diagnostics to read injector correction values and run balance and leak-off tests to find which injectors are actually faulty. We replace only the injectors that need it, fit new seals and clamping bolts, and code the new injectors to the engine so it runs correctly. Call 07498 392333 or book online at our West Bromwich workshop.
Each injector tested
Correction values, balance and leak-off tests find the faulty ones.
Coded to the engine
New injectors are coded with Mercedes-capable diagnostics after fitting.
Book a misfire check
Book an appointment as soon as the idle turns rough or starting gets harder.
Mercedes OM651 injector repair
What our OM651 injector work includes
Clear expectations, no surprises. If anything extra is needed, we explain it first.
- Fault code read and injector correction value check.
- Injector balance and leak-off tests to identify failed injectors.
- Inspection for injector seal leaks and carbon build-up around the injectors.
- Replacement of faulty injectors with new seals and bolts, and injector coding.
- Oil check for diesel dilution, road test and fault memory clear.
Mercedes OM651 injector repair
Common questions
- Do I need to replace all four injectors?
- Not always. Our tests show which injectors are outside tolerance, and we recommend replacing only those unless the others are close to failing too.
- Was my injector covered by a recall?
- Some early OM651 injectors were replaced under Mercedes campaigns. A Mercedes dealer can check your vehicle history, and we can advise when we see the car.
- What is the black tar around my injector?
- That is usually a leaking injector seal letting combustion gas escape. It should be fixed early — the longer it runs, the harder the injector is to remove.
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Serving drivers across the local area
We provide mercedes om651 injector repair for customers from across the region — book online or call us.
Experts in mercedes om651 injector repair
Tell us your car and symptoms, we will advise honestly.
Serving West Bromwich, West Midlands and surrounding areas towns. Message or call and we will outline likely costs before we book you in.