Ford Ranger: P5AT 3.2 Injector Copper Crush Washer Blow-Out

The P5AT 3.2 TDCi uses copper crush washers to seal each injector in the cylinder head. These washers harden and lose their seal under the thermal cycling of diesel combustion, allowing hot combustion gases to escape past the injector body. The escaping gases carbon-foul the injector bore, can damage the injector body clamping threads in the head, and draw oil vapour into the combustion chamber. Left unaddressed, the injector seating surface in the aluminium head can be eroded, requiring expensive specialist machining or head replacement.

• Carbon fouling or dark staining visible around injector bases on the cylinder head
• Ticking or light knocking from the top of the engine increasing with engine speed
• Rough idle or single-cylinder misfire that worsens when cold
• White or grey emulsion on the oil filler cap
• Elevated oil consumption from combustion gases pressurising the crankcase

With the engine cold, open the bonnet and look for carbon tracking or dark staining around the base of each injector where it enters the cylinder head — this indicates gas blow-by. Also check the oil filler cap interior for excessive white emulsion beyond minor condensation, which suggests combustion gas entry into the crankcase. If a workshop inspection is possible: Any ticking or light knocking from the top of the engine that increases with revs warrants borescope inspection of the injector seats.

Parts involved: Fuel injector.

$600 to $4,500 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

• “Have the fuel injectors ever been removed, and if so, were the copper crush washers replaced at that time?”
• “Has the engine ever had a misfire or rough idle diagnosed by a workshop, and what was the cause?”
• “Is there any carbon staining or oil weeping visible around the injector bases that you are aware of?”

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.