| Job | Labour | Independent | Main dealer |
|---|---|---|---|
| Diagnosis (leak-back / contribution test) | 0.5-1 hr | £50-£120 | £90-£180 |
| One diesel injector - reconditioned, coded | 1-2 hrs | £200-£400 | - |
| One diesel injector - new OE, coded | 1-2 hrs | £350-£600 | £450-£800 |
| Full set of 4 - reconditioned, coded | 2-4 hrs | £700-£1,500 | - |
| Full set of 4 - new OE | 2-4 hrs | £1,200-£2,200 | £1,600-£3,000 |
| Petrol injector (each) | 0.5-1.5 hrs | £80-£200 | £150-£350 |
| Seized injector extraction | varies | +£100-£400 each | +£150-£500 each |
Guide prices including fitting, new seals and washers, and coding where required. Dealers generally fit new original parts only, which is why the recon rows are blank on their side. The seized-injector row is the wildcard - more on that below.
Diagnose Before You Buy Anything
Injector faults leave evidence. A leak-back test measures how much fuel each injector returns to the tank - a worn one returns far more than its neighbours and identifies itself on the spot. A cylinder contribution test via the scanner shows which cylinder is not pulling its weight, and injector circuit codes (P0201 through P0204) name the cylinder electrically. Low rail pressure codes like P0087 can also be caused by a single leaking injector dragging the whole rail down. The point: for £50-£120 of testing, you replace the injector that is faulty - not the four that might be.
Reconditioned vs New - The Honest Answer
A properly remanufactured injector from the recognised specialists (genuine Bosch, Delphi or Denso exchange programmes, or an established UK diesel specialist with test-bench certificates) is rebuilt with new nozzles and internals, flow-tested, and supplied with a warranty - at roughly half the price of new. That is a legitimate saving and most independents fit them daily. What to avoid is the other kind of "recon": unbranded internet injectors with no test certificate, which are a gamble on the exact component your engine's smooth running depends on. If the price looks impossibly good, the flow testing did not happen.
Diesel injectors sit in the cylinder head sealed by a copper washer, and on high-mileage engines - vans especially - carbon builds around the body until the injector is effectively welded in. An honest quote for injector work on an older diesel always carries the caveat "provided they come out freely". If one is seized, extraction with pullers, heat or on-car machining adds £100-£400 per injector, and the worst cases need the cylinder head off. This is not the garage inventing costs - ask upfront how they price extraction, and you will hear the difference between a good garage and a chancer.
Coding Is Not Optional
Every modern common-rail injector carries a calibration code - a string of characters describing exactly how that individual injector flows, which must be programmed into the ECU when it is fitted. Skip the coding and the engine runs on wrong assumptions: rough idle, smoke, imbalance, and long-term damage in the worst cases. If a bargain quote does not mention coding, it is not a complete job. It takes minutes with the right scanner, and it should be itemised.
How to Avoid Being Ripped Off
- Ask which cylinder, and how they know. Leak-back figures or contribution readings are your evidence. "They're all getting on a bit" is not a diagnosis, it is a sales pitch.
- One faulty injector does not condemn four. On a very high-mileage engine there is a fair argument for doing the set while access is paid for - but that is your call to make with the evidence in front of you, not a default.
- New seals and washers, always. A reused copper washer causes combustion gas to chuff past the injector - the tick-tick-tick that ruins an otherwise good job. They cost pennies; check they are on the invoice.
- Cheap fuel and biofuel-heavy blends are injector killers. If injectors failed young, consider where the car fuels up. Contaminated fuel can take out a full set at once - and that can be an insurance or supplier claim, not a repair bill.
A Full Set on an Older Van or Car?
A four-injector bill with extraction risk on a 150,000-mile van is a proper crossroads: potentially £1,500+ into a vehicle whose value may not be much more. Sometimes it is still right - a van that earns its keep, with a known history, is worth reinvesting in. Sometimes it is the moment to move on. The Keep or Sell calculator will run your actual numbers and show you the reasoning either way.
