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Repair diesel engine air intake and exhaust systems

Level / 4
Credits / 4

PurposeThis unit standard is for people in the automotive repair industry. People credited with this unit standard are able to: inspect an induction system on a diesel engine, and repair faults; inspect an exhaust system on a diesel engine, and repair a faulty or noisy system; and service the turbocharger on a diesel engine.

Subfield / Motor Industry
Domain / Automotive Fuel Systems and Exhaust
Status / Registered
Status date / 25 January 2008
Date version published / 25 January 2008
Planned review date / 31 December 2012
Entry information / Recommended: Unit 24179, Demonstrate knowledge of a forced air intake system on an engine,or demonstrate equivalent knowledge and skills.
Accreditation / Evaluation of documentation and visit by NZQA and industry.
Standard setting body (SSB) / NZ Motor Industry Training Organisation (Incorporated)
Accreditation and Moderation Action Plan (AMAP) reference / 0014

This AMAP can be accessed at

Special notes

1Legislation relevant to this unit standard includes but is not limited to – Health and Safety in Employment Act 1992; Land Transport Rules: Heavy Vehicles 2004, Rule 31002; Vehicle Repair 1998, Rule 34001.

2Land Transport Rules are produced for the Minister of Transport by Land Transport New Zealand. These rules are available online at

3Definitions

Service information may include but is not limited to – technical information of a vehicle, machine, or product detailing operation; installation and servicing procedures; manufacturer instructions and specifications; technical terms and descriptions; and detailed illustrations. This can be accessed in hard copy or electronic format and is normally sourced from the manufacturer.

Suitable tools and equipment means industry approved tools and equipment that are recognised within the industry as being the most suited to complete the task in a professional and competent manner with due regard to safe working practices.

4For this unit standard, it is essential that the practical assessment evidence is obtained in the workplace under normal workplace conditions.

Elements and performance criteria

Element 1

Inspect an induction system on a diesel engine, and repair faults.

Performance criteria

1.1Safe working practices are observed throughout the task in accordance with legislative requirements.

Rangepersonal safety, safety of others, vehicle or machine safety, workshop safety, environmental safety, tools and equipment safety.

1.2Suitable tools and equipment are selected and used to enable the induction system to be inspected, tested, and repaired in accordance with service information.

1.3Loose and damaged components are repaired in accordance with service information to ensure full serviceability of the induction system.

1.4Air flow restriction in the air cleaners is cleared to comply with manufacturer specifications.

1.5The induction system is pressurised and tested for air leaks in accordance with service information.

1.6Air leaks in the induction system are rectified in accordance with service information.

1.7The engine is run to determine that induction pressure levels are within manufacturer specified limits.

Element 2

Inspect an exhaust system on a diesel engine, and repair a faulty or noisy system.

Performance criteria

2.1Safe working practices are observed throughout the task in accordance with legislative requirements.

Rangepersonal safety, safety of others, vehicle or machine safety, workshop safety, environmental safety, tools and equipment safety.

2.2Suitable tools and equipment are selected and used to enable the exhaust system to be inspected and repaired in accordance with service information.

2.3The exhaust system is inspected and any leaks are located and their source(s) identified in accordance with service information and legislative requirements.

2.4The engine is operated to reproduce the offending noise, and to verify whether the source of the noise is the exhaust system.

2.5The exhaust system is checked for loose internal parts and blockages, and any faults are rectified in accordance with service information.

2.6Damaged components, and components that are the source of the noise, are replaced to comply with manufacturer specifications and Land Transport Rules.

2.7Corroded, damaged, and loose parts are repaired to comply with manufacturer specifications.

Rangemay include but are not limited to – pipes, stacks, mufflers, mountings;

removed, tightened, welded, secured, replaced with new parts.

2.8The exhaust system is checked to ensure it is aligned, mounted, and securely attached.

Rangeno system vibration, transmission of noise, system not mounted under tension, location of mounts and their condition.

Element 3

Service the turbocharger on a diesel engine.

Performance criteria

3.1Safe working practices are observed throughout the task in accordance with legislative requirements.

Rangepersonal safety, safety of others, vehicle or machine safety, workshop safety, environmental safety, tools and equipment safety.

3.2Suitable tools and equipment are selected and used to enable the turbocharger system to be serviced in accordance with service information.

3.3Cleanliness is observed at all times when working on the turbocharger system.

Rangeenvironment, personal cleanliness.

3.4Faults identified by a visual inspection of the turbocharger system are identified and rectified in accordance with service information.

Rangemay include but is not limited to – loose or damaged components, damaged pipes and fittings, hoses, intake and exhaust ducting, linkage, noisy operation.

3.5Air filter is renewed at a specified time or distance interval with one that meets manufacturer specifications.

3.6Engine oil and oil filter that meet manufacturer specifications are changed at the manufacturers or company service schedule’s specified time or distance interval.

3.7Associated exhaust system components are checked for operation and any faults recorded in accordance with service information.

3.8Turbocharger unit and its operation are checked and any faults recorded in accordance with service information.

Please note

Providers must be accredited by NZQA, or an inter-institutional body with delegated authority for quality assurance, before they can report credits from assessment against unit standards or deliver courses of study leading to that assessment.

Industry Training Organisations must be accredited by NZQA before they can register credits from assessment against unit standards.

Accredited providers and Industry Training Organisations assessing against unit standards must engage with the moderation system that applies to those standards.

Accreditation requirements and an outline of the moderation system that applies to this standard are outlined in the Accreditation and Moderation Action Plan (AMAP). The AMAP also includes useful information about special requirements for organisations wishing to develop education and training programmes, such as minimum qualifications for tutors and assessors, and special resource requirements.

Comments on this unit standard

Please contact the NZ Motor Industry Training Organisation (Incorporated) if you wish to suggest changes to the content of this unit standard.

 New Zealand Qualifications Authority 2018