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Choosing and Maintaining a Gas Conversion: Safety, Servicing and Roadworthy

08 Jul 2026 Ethan Lowery
LovatoautogasLPGsafetyservicingroadworthy

A gas conversion is a fuel system fitted to a vehicle, so it is chosen, installed and maintained to a standard, not bolted on and forgotten. Done properly it runs for years and saves real money per kilometre. Done badly, or left unserviced, it costs more than it saves and, because it stores fuel under pressure, it has to be safe. This note covers how to choose the right conversion, what compliance means in South Africa, the servicing the system needs, and the wear points a gas engine has that a petrol engine does not.

Choosing a conversion that suits the engine

The conversion has to match the engine, not just the vehicle. Confirm these before you order:

  • Injection type. A conventional sequential kit suits a port-injection petrol engine. Direct-injection petrol engines need a different approach, so name the exact engine, not just the model.
  • Cylinder count and power. The injector count follows the cylinders, and the reducer is sized to the engine’s power. An undersized reducer runs out of gas at full load.
  • Tank space and range. LPG fits as a cylindrical boot tank or a toroidal tank in the spare-wheel well. Choose the tank to the space and the range you need, and account for the weight.
  • Fuel availability on your routes. LPG is widely available in South Africa; CNG refuelling is limited to a few areas. Match the fuel to where you actually drive.
  • Payback. The saving per kilometre has to repay the conversion over the distance you drive, so high-mileage vehicles justify a conversion far sooner than low-mileage ones.

Safety and roadworthy in South Africa

A gas system stores fuel under pressure, so who fits it and how it is certified matters. In South Africa, LPG vehicle installations should be carried out by a registered LP Gas installer and issued with a certificate of conformity for the installation. That certificate is your evidence that the system was installed and pressure-tested to the applicable standard, and it is what a testing station or an insurer will want to see. Keep it with the vehicle papers.

For roadworthy and registration, requirements are enforced by the testing stations and the provincial authorities, and they do change, so confirm the current requirement with a registered installer and your local testing station rather than assuming. The general expectation is that the installation is certified, the tank is within its valid certification, and the conversion is disclosed. Do not treat a conversion as invisible to roadworthy: declare it and carry the paperwork.

The tank itself is a certified pressure vessel with a stamped certification and a service life. An LPG tank has to be inspected and recertified or replaced at the end of that life, and a CNG cylinder, being a high-pressure vessel, is inspected on a stricter schedule with a stamped expiry. Never fit or keep a tank past its certification, and never modify a tank or its multivalve.

Servicing a gas system

A gas system is low-maintenance, not no-maintenance. The routine items:

  • Gas filters. A sequential system has a filter (often more than one, a coarse liquid-phase and a fine vapour-phase filter on LPG) that has to be replaced on schedule. A blocked filter starves the engine at load. Follow the kit’s service interval.
  • Reducer service. The reducer has internal diaphragms and seals that age. Service it at the manufacturer’s interval, and check the coolant plumbing to it for leaks and airlocks, because a reducer starved of coolant heat vaporises poorly.
  • Injector check. Gas injectors can gum or drift over high mileage. Have them checked and the ECU calibration verified if the drive deteriorates or fuelling trims wander.
  • Leak and gas-tightness check. Have the whole system leak-tested at service. A gas smell, hissing or a drop in the level with the engine off is a leak: stop using gas and have it checked before you drive on gas again.
  • Tune verification. After any major service, have the gas map checked on OBD so the dose still matches the engine.

Wear points on an engine that runs on gas

Gas burns cleaner than petrol, which keeps oil and plugs cleaner, but it also burns drier and hotter, and that shifts a few wear points:

  • Spark plugs. Gas can want a slightly different plug specification or gap, and plugs work a little harder. Check them on the service schedule and replace with the specification the installer recommends for gas.
  • Valve seats. Older engines built without hardened exhaust valve seats relied on the lead, and later on additives, in petrol to cushion the valve seats. Gas runs dry, so on an at-risk older engine a valve-saver (flashlube) system that meters a lubricant into the intake protects against valve-seat recession. Confirm whether your engine needs one.
  • Petrol side. The petrol system still has to work, because the engine starts on petrol every time. Do not let the petrol fuel go stale or the petrol injectors seize from disuse. Running a tank of petrol through the engine periodically keeps the petrol side healthy.

Look after the filters, the reducer and the tank certification, keep the tune verified, and protect the valve seats on an older engine, and a gas conversion runs reliably for the life of the vehicle.

How to order or request a quote

Tell us the vehicle, the engine and how you drive, and we will confirm the right Lovato conversion, the reducer and tank to suit it, and the service parts to keep it running, with the lead time. Order genuine Lovato components by part number on Omnipart.