Do I need the cylinder head off for a seized injector or snapped glow plug?
Seized injector or snapped glow plug? The head may not need to come off
The short answer
Diesel injectors and glow plugs can corrode or carbon up until they will not come out. Forced, they snap. The usual fallback is to remove the cylinder head, which is a big, expensive job. With specialist hydraulic pullers, drilling jigs and extraction kits, most can be removed with the head still on the engine, including ones already snapped or with stripped threads.
Signs you may have one
- Another garage has said an injector or glow plug “won’t come out”
- A glow plug has snapped during replacement
- Hard starting, misfire or smoke after injector or glow plug work
- You have been quoted for cylinder head removal to replace an injector
Why it matters who does it
Each failed attempt makes the next one harder. Snapping a second time, or damaging the thread in the head, is what turns an extraction into a head job.
What to do now
- Stop working on it if it will not come out with normal force.
- Ring us with the make, model and engine before agreeing to a head removal elsewhere.
- Garages can send the vehicle, or the cylinder head on its own.
Draft Technical wording to be reviewed by PK before publishing.