Injection Pump Leakage: Something to Worry!


    – Injection pump leakage: causes

    – Injection pump leak: cost of repair

Not only are leaks in an engine unpleasant (odours, stains…), but they can also cause serious malfunctions. This is the case for injection pump leaks. What causes these leaks, what are the engine’s consequences and how to deal with this problem?

Injection pump leaks: causes

Leaks will differ according to the type of injection pump.

Rotary pumps

These are the pumps that equipped the old generation of diesel engines with indirect injection.

Although they are no longer produced, many of these engines are still in circulation, and their relative obsolescence further accentuates the risks of leakage, which are of two kinds.

It can be a leak at the front bearing. The pumps are driven by the timing system and therefore support a pulley on their central shaft. At this point, the pump’s internal sealing (filled with diesel) is ensured by a lip seal, which is susceptible to leakage.

The consequences are as follows:

    – Diesel oil leaks out and can damage the timing belt with a risk of engine failure;

    – Air can enter the pump and disrupt the diesel supply to the engine.

It would help if you replaced the seal and sometimes the bearing. The removal of the injection pump is necessary.

It may also be a leak in the pump cover. The injection pump has an upper cover, through which an acceleration shaft and a stop shaft pass, and these two shafts are often subject to leakage.

The consequences are as follows.

    – the diesel spreads outside ;

    – stains that form under the vehicle and give off an unpleasant fuel smell;

    – the engine operation is rarely affected.

In this case, you must replace the O-rings on the shafts after removing the pump cover. This operation is performed with the pump in place.

The high-pressure pump

This pump is fitted to direct injection diesel vehicles (HDI).

Like the injection pump, it is driven by a pinion through the distribution. The leakage risks are located at this level, often due to a play in the front bearing. More rarely, the pump casing can leak (it is also filled with diesel).

The consequences are as follows.

    – Play in the front bearing is often a sign of internal pump destruction.

    – Seepage in the pump casing is a sign of a leaky seal due to the high pressure inside (up to 2,000 bar!).

In both cases, the only solution is to replace the high-pressure pump.

Good to know: apart from the pump, the high pressure can be the cause of leaks at the pump’s connection and the high-pressure pipe leading to the common rail supplying the injectors. In this case, the solution is to replace the injection pipe and follow the manufacturer’s torque tightening recommendation when reassembling.

Injection pump leak: cost of repair

Types of leaks

Injection pump

High-pressure pump

Front spinnaker seal leak

Pump removal and repair: approximately $500

Pump replacement: depending on the manufacturer, from $1,000 to $1,500 (including labor)

Cover replacement (indirect injection) or pump body replacement (direct injection)

$50 to $60

Pump replacement: depending on the manufacturer, $1,000 to $1,500 (including labor)

Leaky hose connection

None (hose tightening)

Replacement of the HP hose: $50 to $80

You can read more here:

Cars and Vehicles: What is Direct Injection System

Injection Pump – Just What You Should Know

Hope the above helps you out. Next time your mechanic talks about an injection pump leakage issue, you will better understand what he is talking about. Remember to share this post and jot down your request for another topic related to cars and vehicles.

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