9.2 Engine/Driveline, Liquid Fuel & LPG/CNG Systems

Engine and driveline condition

Inspect engine, gearbox, transfer case, differential, and other driveline mountings for security. Reject a bent or severely damaged drive shaft; insecure/damaged flange; defective support bearing; worn or damaged universal-joint spider bearing; unsafe rubber coupling; spline wear beyond manufacturer specification; or universals fitted contrary to manufacturer specification.

Engine/transmission modifications require LVV or accepted overseas proof unless Table 13-1-1 excludes them. Fitting or upgrading a turbocharger/supercharger, modifying a wastegate, or rechipping a turbo engine’s control unit is specifically described as requiring LVV certification. An externally venting wastegate cannot be certified. Match the plate description to the actual engine and modifications.

Liquid-fuel system

Page 13-2 rejects a noticeable fuel leak. Inspect under operating conditions appropriate to the system; do not create a dangerous leak test. A mere historic stain is not automatically a noticeable active leak, while a forming drop, wet seepage, or fuel odour with visible source requires action.

Reject corrosion damage, cracking, or other damage within 150 mm of a tank mounting; insecurity or corrosion affecting the tank mounting; a loose line likely to be damaged; a severely damaged/excessively corroded pipe; a damaged/perished hose; an insecure pump; or a missing, insecure, spill-prone, or temporary-use filler cap/seal.

The current page does not prescribe fuel-line clips every 300–450 mm, SAE hose codes, approved clamp brands, or a numeric 20% strap-loss test. Use its actual security, condition, leak, and modification criteria.

A modified tank, filler, line route, pump, or fuel-cell installation must meet Table 13-2-1 or carry the required certification evidence. Consider separation from occupants and heat sources through the applicable VIRM provisions.

LPG and CNG

If an LPG/CNG system is in working order, the vehicle must display a current alternative-fuel inspection certificate. This is different from the installation certificate, which the page states is not required for WoF issue.

Reject an LPG/CNG component that is insecure, damaged, deteriorated, or otherwise unsafe as listed; an insecure/damaged gas line; a noticeable gas leak; or corrosion damage, distortion, or fracture within 300 mm of a tank mounting. Use an approved safe leak-detection method—never an open flame.

The VIRM page does not tell the WoF inspector to calculate universal LPG ten-year cylinder testing or CNG annual/hydrostatic intervals. The certification specialist controls periodic alternative-fuel certification; the WoF inspector verifies the current certificate and the in-service condition. A system that is not working uses the page’s notes to determine treatment; do not assume that merely selecting petrol proves the gas system is outside scope.

Installation of LPG/CNG itself is not an LVV-certification modification, but changes to an existing system require an approved LPG/CNG inspector or organisation as stated.

Inspection sequence

1. Inspect driveline mounts, shafts, supports, joints, and couplings.
2. Identify engine/driveline modifications and match certification evidence.
3. Trace liquid-fuel tank, mounts, pipes, hoses, pump, filler, and cap.
4. Look for a noticeable leak under safe operating conditions.
5. Identify LPG/CNG status and verify the current inspection certificate.
6. Inspect gas components, lines, leakage, and the 300 mm tank-mount zone.
7. Record the exact component, location, and evidence.

Scenario

An LPG vehicle has a sound-looking cylinder but its alternative-fuel inspection certificate has expired. If the LPG system is in working order, the expired certificate requires rejection; visual appearance alone cannot replace specialist periodic inspection.

Status, leakage, and evidence

Trace a suspected liquid leak to distinguish fuel from water, oil, coolant or old protective coating. Use smell cautiously and never taste or expose fuel to ignition. A capless filler is acceptable when its seal is present, secure and unlikely to spill; it should not be failed merely for lacking a screw cap. A temporary-use cap is separately rejected.

For LPG/CNG, confirm whether the system is in working order under the VIRM notes rather than accepting a dashboard selector position. Match the alternative-fuel certificate to the vehicle and current period. If gas is suspected, follow site emergency and ventilation procedures first; certification does not take priority over controlling an immediate hazard.

Final fuel checkpoint

After visual inspection, operate the vehicle only as needed and safely recheck pressurised areas for a noticeable leak. Confirm filler closure after testing and ensure no tool or rag remains near fuel or exhaust. Treat certification documents as identity-specific records: compare registration/VIN and validity rather than accepting a loose label. If a fuel modification also affects structure, emissions or occupant separation, open those pages and record each decision independently.