Used LPG Car: What to Check Before You Buy

Buying a used LPG car makes sense for one reason: the fuel is far cheaper. On 4 October 2026 the Italian national average for LPG was 0.777 euro per litre, against 2.067 for petrol and 2.265 for diesel [3]. But a used bifuel car hides a cost many buyers find out about too late: the gas tank has an expiry date. This guide covers what to check before you sign.

Why LPG pays off (and when it does not)

The advantage is cost per kilometre. With LPG at about 0.78 euro per litre, even allowing for higher consumption than petrol, the refuelling bill drops sharply. The saving is real mostly if you drive a lot each year: on low mileage the gap narrows, and a single tank replacement can wipe out years of savings.

Prices also move, and LPG on motorways costs noticeably more than on the regular network, so run the numbers on your own driving.

The 10-year rule: the tank expires

The key point: the LPG cylinder or toroidal tank must be replaced every 10 years [1][2]. The clock starts at installation for a factory-fitted system, and from the date on the tank or the test certificate for an aftermarket one. Only the tank is replaced, not the whole system [2].

What this means when you buy: if the tank expires in a few months, budget for replacement right away. The sources we consulted put the cost between roughly 150-200 and 500 euro, depending on tank type and workshop [2]. Some cars with unusual tanks can cost far more, so ask for a quote before you buy.

How to check the tank date

1. Look for the manufacture date stamped on the tank, usually under the boot floor, in the spare wheel well.
2. Check the registration document: the LPG system must be recorded on it.
3. Ask for the installation and test paperwork, with the installer's certificate.
4. Confirm the components are approved to ECE/UN 67/01 [2].

If the seller cannot tell you the date, have an authorised installer look at the car before you decide.

Penalties for an expired tank

Driving with a tank older than 10 years exposes you to an administrative fine and the vehicle being impounded [1]. The amounts quoted by sources differ, but the substance is the same: a car with an expired tank is not compliant, will not pass its inspection, and after the sale the problem is yours. So have the seller fix it, or take the cost off the price.

Car inspection and the LPG system

The car inspection follows the general rules: the first at 4 years from first registration, then every 2 years [2]. It costs 54.90 euro at the Motorizzazione and 78.96 euro at an authorised centre [2]. LPG has no separate periodic tank inspection, though a periodic check at an authorised workshop is recommended [1]. Methane is different: its cylinders must be inspected every 4 or 5 years depending on approval [1], so do not mix the two fuels up.

Practical checks on the test drive

• The engine should start on petrol and switch to LPG without jerks.
• Check there is no gas smell in the boot or engine bay.
• Make sure the fuel switch works and the LPG level is readable.
• Inspect the reducer, injectors and hoses: leaks or cracks are a warning sign.
• Look for a service record covering the gas system, done alongside the engine service.
• Do a cold start and a warm run: some starting problems only show up in one of the two.

Pricing the tank into the deal

A practical rule: if the tank expires within 12 months, subtract the replacement cost from the asking price. With a figure of 150-500 euro [2], that is a concrete bargaining point. If the tank was just replaced, you have 10 years of peace and the car is worth more, all else equal.

The takeaway

Before buying a used LPG car: read the tank date, ask for the test paperwork, get a replacement quote, check the system and the registration document, and work out your yearly mileage. Do that and you avoid the surprise bill and keep the fuel saving working for you.

Sources

[1] Motor1, Revisione bombole GPL e metano, quando farla e quanto costa. [2] Autoblog, Revisione bombole GPL: come si fa, costo, sanzioni. [3] Finanza.com, Prezzo dei carburanti al 4 ottobre 2026.