MajorCommonFluid Leaks

Renault Megane: 1.9 dCi Injector Return Pipe O-Ring Seal Leak

1.9 dCi Injector Return Pipe O-Ring Seal Leak is a common fluid leaks fault on the Renault Megane on the 2002–2008 cars, and we rate it major. Putting it right costs $350 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 Renault Megane.

Vehicle: Renault Megane
Engine: 1.9L
Years: 2002–2008
Fuel: diesel
System: Fluid Leaks

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

All Renault Megane faults27 documented faults on this model

What you are looking at

What goes wrong

The F9Q 1.9 dCi engine uses rubber O-ring seals at the injector return pipe unions that harden and crack with age. Diesel weeps from the injector body seals producing a fuel smell and oil contamination around the top of the engine. If air is drawn back through a leaking seal it can cause rough running or hard starting. Documented in NZ and Australian diesel workshop writeups as a routine age-related fault on 2002–2008 Megane 1.9 dCi.

What you would notice

Diesel smell from engine bay after driving
Visible diesel weeping around injector tops or return pipe unions
Oily residue on engine cam cover near injector rail
Rough idle or hard starting if air enters the system

How to check it

Where to look. Top of engine, injector return rail unions at each injector

Inspect the top of the engine around each injector return pipe union for diesel staining or wetness.
Wipe area clean and re-inspect after a short test drive.
Check for fuel smell with engine at operating temperature.

Parts involved: Fuel injector.

What it costs to put right

$350 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

“Have the injector return pipe O-ring seals been replaced?”
“Is there ever a diesel smell from the engine bay?”
“When were the injectors last serviced?”

Now check the Renault Megane 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 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.

Renault Megane buyer questions

Is 1.9 dci injector return pipe o-ring seal leak serious on a Renault Megane?

We rate it major and common on the Renault Megane. The F9Q 1.9 dCi engine uses rubber O-ring seals at the injector return pipe unions that harden and crack with age. Diesel weeps from the injector body seals producing a fuel smell and oil contamination around the top of the engine. If air is drawn back through a leaking seal it can cause rough running or hard starting. Documented in NZ and Australian diesel workshop writeups as a routine age-related fault on 2002–2008 Megane 1.9 dCi.

How much does it cost to fix on a Renault Megane?

$350 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 Renault Megane years are affected?

Our research records this fault on the 2002–2008 Renault Megane. 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?

Inspect the top of the engine around each injector return pipe union for diesel staining or wetness. Wipe area clean and re-inspect after a short test drive. Check for fuel smell with engine at operating temperature. Look here: Top of engine, injector return rail unions at each injector