Fuel Injector Repairs

Worried about strange noises or smells in your Mercedes?

It could be a fuel injector leak

'Black Death'

The usual type of fuel injector leak is sometimes referred to as ‘Black Death’.

It’s a common but serious problem in Mercedes Diesel engines, that can cause major issues if not addressed.

It refers to the messy carbon buildup that fills the space around the fuel injectors, pipes and wiring.

A hand holds several car parts, including a fuel injector, a bolt, and a copper washer. In the background, a car workshop with several white vans—some with open hoods—and a banner that reads "Bosch Car Service" is visible. The scene subtly hints at the meticulous work involved in Mercedes Fuel Injector Repairs.

What causes it?

It’s caused by erosion of the tiny copper washers that seal the fuel injectors to the cylinder head.

Hot diesel fuel that should be burnt inside the engine, is allowed to escape, sticking to the top of the engine as a solid.

Imagine black coal or a dirty barbecue, that’s what the top of your engine will look like.

How to spot Injector Leaks or Black Death

  • Exhaust Smells in the cabin or air conditioning
  • Chuffing or compressed air noise
  • Carbon deposits on the engine or underside of bonnet
  • Poor fuel consumption

Is my Mercedes at risk of Fuel Injector Leaks?

Pre-2006 Sprinters and Vitos are the most susceptible to fuel injector leaks. But it can affect all models of Mercedes Diesel engines.

Of the newer engine variants, injector leaks are often seen on the OM642 V6 engine.

Our Proven Fuel Injector Repair Process

Our fuel injector repair process requires special tools for removing the fuel injectors and grinding the sealing surfaces. The good news is that the fuel injectors can usually be salvaged and reused. This reduces cost compared to replacement of the fuel injectors.

  • Remove un combusted material using special tools and chemicals.
  • Remove injectors using specialist pullers, including hydraulic for very severe cases.
  • Clean and inspect fuel injectors for damage.
  • Replace injector sealing seat if required.
  • Machine cylinder head injector sealing surface.
  • Replace injectors using correctly measured sealing washers and hold down bolts to manufacturers torque specifications.
  • Repair or replace injector fuel leak off rail as required.
  • Leak test reinstalled injectors.

So what should I do?

The quicker you have injector leaks repaired, the easier and cheaper it is.

As the engine runs longer with leaking injectors, the amount of carbon buildup will increase, and it’s really difficult to remove.

Plus, the fuel injectors can get seized inside the engine.

As soon as you hear or smell anything unusual from your Mercedes diesel engine, at least get it checked to make sure your injectors aren’t leaking.

mercedes glow plug warning light being repaired by eurostar diesels technician on vito van

The Other Type of Injector Leak - Fuel Leaks

Diesel fuel leaks can also occur. Unlike the Black Death problem, there will be no carbon but rather a messy diesel leak. It will usually drain towards the rear of the engine and then down to the road. So it’s important to get this fixed urgently if you notice diesel fuel dripping. Diesel leaks can come from the following areas: 

  • Fuel Leak Back or Return Line Hose
  • Injector High Pressure Steel Pipes
  • Cracked Fuel Injector Body

Repairing Diesel Fuel Leaks

Diesel fuel leaks can be repaired by replacing the faulty or cracked part. Contact us today through our online booking enquiry form or by phone if you’re experiencing any of these problems and we’ll be glad to assist.

Make a Booking with our Team:

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