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Land Rover Discovery: Td5 'oil in the loom' — engine oil wicking up the injector harness

Td5 'oil in the loom' — engine oil wicking up the injector harness is a very common electrical fault on the Land Rover Discovery on the 2000–2004 cars, and we rate it major. Putting it right costs $300 to $900 at New Zealand independent workshop rates. Below is what goes wrong, the symptoms to notice on a test drive, where to look, and what to ask the seller before you hand over any money. It is one of 27 documented faults on the Land Rover Discovery.

Vehicle
Land Rover Discovery
Years
2000–2004
Fuel
diesel
System
Electrical

This page covers the Land Rover Discovery as a model. Some faults only affect particular engines or build years — enter a plate below to narrow the list to one car.

All Land Rover Discovery faults27 documented faults on this model

What you are looking at

A single common-rail diesel fuel injector photographed against a plain background.Example of the part — not this vehicle

A common-rail diesel injector. Contamination damages the nozzle at the tip.

Panoha · CC BY-SA 3.0 · Wikimedia Commons

What goes wrong

On the Discovery 2's Td5 diesel, engine oil migrates past the injector harness connector seals and wicks along the copper strands of the loom, eventually reaching the ECU connector. It causes rough running, misfires and in bad cases ECU damage. It is one of the most famous Td5 faults; the fix is a modified/updated injector harness and cleaning the contamination out of the connectors. Cheap if caught early, expensive if the ECU is soaked.

What you would notice

  • Rough idle or misfire, often when warm
  • Oil visible inside the red ECU connector plug
  • Intermittent limp mode or hesitation

How to check it

Where to look. Injector harness on top of the engine, running to the ECU connector near the battery

  1. Unclip the engine ECU connector (behind the battery/left inner guard) and look for engine oil inside the plug — even a film means the loom is wicking.

  2. Check for an invoice for a replacement injector harness.

  3. Listen for misfires at idle when warm.

Parts involved: Fuel injector.

What it costs to put right

$300 to $900 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.

Ask the seller

  • “Has the injector loom been replaced with the updated part?”
  • “Has oil ever been found in the ECU plug?”

Now check the Land Rover Discovery you are actually looking at

Everything above is true of the model, and it is free. What it does not tell you is whether THIS car has been looked after: its odometer history and whether the reading has ever gone backwards, whether there is still money owing on it, whether it has been reported stolen, how many owners it has had and what it is really worth today. That comes from the official records for that plate. Enter the plate for the free details, or get the full history and a market valuation from $13.49.

Not sure what you would be paying for? See what a full KickTyres check includes.

Where this comes from

The failure described above is documented in the sources below. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them.

  • AULRO forum: 'Permanent TD5 injector loom fix' (thread 233690)
  • JGS4x4 technical guide: 'Td5 injector harness explained'

Land Rover Discovery buyer questions

Is td5 'oil in the loom' — engine oil wicking up the injector harness serious on a Land Rover Discovery?

We rate it major and very common on the Land Rover Discovery. On the Discovery 2's Td5 diesel, engine oil migrates past the injector harness connector seals and wicks along the copper strands of the loom, eventually reaching the ECU connector. It causes rough running, misfires and in bad cases ECU damage. It is one of the most famous Td5 faults; the fix is a modified/updated injector harness and cleaning the contamination out of the connectors. Cheap if caught early, expensive if the ECU is soaked.

How much does it cost to fix on a Land Rover Discovery?

$300 to $900 at New Zealand independent workshop rates. That figure is for this job on its own. A car showing the symptoms on this page is usually worth either walking away from or negotiating down by at least the repair figure.

Which Land Rover Discovery years are affected?

Our research records this fault on the 2000–2004 Land Rover Discovery. Build dates move around, especially on imported cars, so treat the range as the years to look hardest at rather than a guarantee either way. The official records tell you the exact build and first registration date for the car in front of you.

How do I check for it before I buy?

Unclip the engine ECU connector (behind the battery/left inner guard) and look for engine oil inside the plug — even a film means the loom is wicking. Check for an invoice for a replacement injector harness. Listen for misfires at idle when warm. Look here: Injector harness on top of the engine, running to the ECU connector near the battery