PROCEDURE WHEN A FUEL VALVE BODY IS SEIZED INSIDE THE CYLINDER HEAD

1. Stop the engine and secure the turning gear; isolate the fuel supply to the unit and drain the fuel from the fuel valve/ high-pressure pipe. Tag the unit not-to-run.
2. Remove the high-pressure fuel pipe and the fuel valve's leak-off/ return connections; remove the fuel valve clamping/ holding-down arrangement (clamp, studs, nuts) so the fuel valve is free.
3. Attempt gentle freeing: apply a suitable penetrating oil/ releasing agent around the fuel valve body/ bore and allow time to soak. Tap the fuel valve body lightly with a soft-faced hammer (never strike the nozzle) to break the corrosion/ carbon bond.
4. Use the fuel valve lifting/ extraction tool: fit the maker's fuel valve puller/ extractor (a threaded puller that grips the fuel valve body and applies a steady axial pull) and apply a controlled pull, rocking gently. Do not use excessive force that could damage the cylinder head bore.
5. If still seized, apply controlled heat: warm the cylinder head bore around the fuel valve (using a hot-air gun/ induction heater or a controlled flame at a safe distance) to expand the head bore relative to the fuel valve, then re-apply the puller. Take care not to overheat or damage the head or the fuel valve.
6. If the fuel valve is still stuck, use a combination of heat and a hydraulic/ mechanical puller, or a slide hammer/ extractor, working progressively. Where the fuel valve is badly seized, it may be necessary to drill/ tap the fuel valve body to fit a puller, or to machine/ cut the fuel valve out (as a last resort, with the head removed) - this is a workshop operation.
7. If all else fails, remove the cylinder head and take it to the workshop where the seized fuel valve can be removed by machining without damaging the head bore; the head bore is then re-machined/ sleeved as required.
8. On removal, inspect the fuel valve bore in the head for scoring, corrosion and damage; clean and, if damaged, re-machine or fit a sleeve/ bush to restore the bore.
9. Refit a new/ overhauled fuel valve with the correct sealing (copper washer/ O-ring), torque the clamp correctly, reconnect the fuel and leak-off lines, and bleed the system.
10. Run the engine and check for fuel leaks and correct injection.