How to Register an LPG Autogas Conversion for Your Car in Sri Lanka

If you're tired of petrol or diesel prices and thinking about running your car on LPG, you can't just fit a tank and drive off. In Sri Lanka, converting a vehicle's fuel system is a formal change to your Certificate of Registration (CR book), and the Department of Motor Traffic (DMT) controls when and how it happens. This guide walks through the eligibility rule, the paperwork, the two offices you'll deal with, and what it costs and changes for your insurance.

Key facts

• A vehicle must be more than 3 years and less than 25 years old (from its registration date) to qualify for fuel conversion, according to the DMT's own published procedure.
• You need the CMT 130 (application for a certificate of weight) and CMT 72 (change of particulars) forms.
• Supporting documents include your revenue licence copy, CR book copy, engine bill copy, and a letter of request.
• If the vehicle is on a lease or hire purchase, you also need a letter from the finance company.
• Approval must come from the Commissioner General of Motor Traffic before any physical conversion work is done.
• The actual weight certificate and conversion sign-off happen at the DMT's Werahera office.
• Installer pricing at a major supplier was quoted at roughly LKR 20,000–130,000 depending on engine type and tank choice, as of November 2026 (citygas.lk) — always confirm the current price with the installer and check it against other quotes.
• Converting the fuel system is a mechanical modification, so you should notify your insurer separately; this is not covered by the DMT paperwork.

Can you convert any car to autogas in Sri Lanka?

No. The DMT's fuel conversion procedure only applies to vehicles that have completed more than 3 years from their date of registration but not yet reached 25 years. A brand-new import can't be converted immediately, and a very old vehicle may fall outside the window too. Check your CR book's registration date before you spend money on a kit or an installer, since the DMT will reject the application if the vehicle doesn't fall inside that band.

This age rule exists for the DMT's internal process, not for the technology itself — conversion kits are available for both older carburettor engines and newer multi-point fuel-injected engines, so the mechanical side isn't the limiting factor. The registration date is.

What documents do you need to convert your vehicle to LPG?

You need a specific set of forms and copies before the DMT's Technical Branch will even look at your file:

• CMT 130 form (application for a certificate of weight)
• CMT 72 form (change of other particulars in the CR)
• A photocopy of your current revenue licence
• A photocopy of the CR book (registration certificate)
• A photocopy of the engine bill
• A letter of request explaining what you want to do
• A letter from the finance company, only if the vehicle is still under lease or hire purchase

If you're still paying off the vehicle, read who keeps the CR book when you lease a car and check your lease terms before you approach the finance company — some lessors are cautious about mechanical changes to a vehicle they still legally own.

How does the DMT approval process work, step by step?

1. Prepare the full document set above and take it to the DMT's Technical Branch.
2. Submit the letter of request along with the forms — this is where you formally ask for permission to change the fuel type.
3. Wait for approval from the Commissioner General of Motor Traffic. This office has to sign off before any conversion work is legal.
4. Take the approval documents and the vehicle itself to the DMT's Werahera office.
5. Get the weight certificate at Werahera — this confirms the vehicle's weight after the conversion equipment (tank, lines, regulator) is fitted.
6. Have the conversion recorded on your CR book once the weight certificate and sign-off are complete.

Skipping straight to an installer without step 3 approved first is the most common mistake — you end up with a car that's mechanically converted but not legally recognised as such, which creates problems later if you try to sell, insure, or transfer it.

Where do you get the actual conversion done?

The physical fitting — the tank, fuel lines, pressure regulator, and either a mixer (for older carburettor engines) or an electronic injection kit (for newer fuel-injected engines) — is done by a private installer, not by the DMT. The DMT only handles the paperwork, the weight certificate, and the Werahera sign-off. Choose an installer with a track record and ask what kind of kit suits your engine type; older pre-2000 engines typically use a simpler reducer-and-mixer setup, while modern multi-point injection engines need an ECU, injectors, and evaporators matched to the original fuel system.

How much does an LPG conversion cost in Sri Lanka?

Pricing depends heavily on your engine size, whether it's carburettor or injection, and the tank size and shape you choose (a doughnut-shaped tank fits in a spare wheel well, while a cylinder tank takes up boot space). One Sri Lankan supplier quoted a range of roughly LKR 20,000 to 130,000 as of November 2026 — this is just one data point, so get at least two or three quotes before deciding, and confirm current pricing directly with installers since fuel and import costs change.

Remember this cost is separate from the DMT's own charges for forms, the weight certificate, and the CR book amendment — ask the Technical Branch what those fees currently are, since they can change.

Do you need to tell your insurer about the conversion?

Yes. Fitting an LPG system changes your vehicle's fuel and mechanical setup, which is the kind of modification most insurers expect you to disclose. If you don't, and something goes wrong with the gas system — a fire, a fuel-line fault — your insurer could question the claim because the policy was written for the vehicle's original configuration. Call your insurer before or right after the conversion, and ask them to note it on the policy. If you're shopping around, compare a few insurers' views on modified fuel systems rather than assuming they all treat it the same way.

Does autogas change your revenue licence or require a new emission test?

Your revenue licence itself is tied to the vehicle's registration details, not directly to the fuel type, but once the CR book is amended to show the conversion, make sure your next renewal reflects the updated particulars. A Vehicle Emission Test (VET) certificate is already required for revenue licence renewal regardless of fuel type, so after conversion you'll be tested on whatever fuel the car is actually running on at the time.

What should you check before choosing an installer?

• Ask whether the kit suits your specific engine (carburettor vs fuel injection) rather than a generic one-size-fits-all setup.
• Ask about the tank type and where it will sit — a doughnut tank in the spare wheel well keeps your boot space, a cylinder tank doesn't.
• Ask if the installer helps with or explains the DMT paperwork, since a fitter who's done this before can save you a lot of back-and-forth.
• Get the installer's contact details and any warranty on the kit and fitting in writing.
• Don't let anyone install the tank and lines before your DMT approval comes through — undo that order and you risk an unregistered modification.

Should you convert at all before buying or selling?

If you're car shopping and want a vehicle that already runs on autogas, say so clearly when you post an ad or search listings on /vehicles, since a pre-converted car with the paperwork already done saves the next owner this whole process. If you're buying a used car, ask the seller directly whether it has ever been converted and whether the CR book shows it — an undocumented gas tank is a safety and legal red flag, not a selling point. For general buying precautions, see /safety-tips, and compare asking prices on /price-check before you commit. If you still have questions specific to your vehicle's age or lease status, ask in the Wahanaya forum — other owners who've been through the DMT process can tell you what to expect at your local office.

Sources

• Department of Motor Traffic - Registration of Ownership Transfer / Change of Attributes
• Department of Motor Traffic - Registration of Ownership Transfer
• City Gas - Auto Gas Conversions