What are the current LPG tank options?

All LPG tanks fitted by Go LPG! are made of 3/8" thick (8mm) steel and are far stronger than any Petrol or Diesel tank. The welded seams and joints are X ray tested early in the quality control process. Tanks are then tested to many times their ordinary working pressure, certified individually and must conform to EEC Directive R67/01.

Tank Shape

LPG tanks are only supplied as Cylinders or Toroidals (Polo Mint Shaped).

All LPG tanks are pressure vessels. They have to be designed to withstand the pressure held within. That means no corners, and, consequently no square or rectangular tanks. To understand why this is so, consider any type of Hot Water tank or Boiler. As pressure inside a square or rectangular shape is increased it will try and reform itself into a rounded shape, just like a Balloon does. This would result in failure at any corner. The design solution is to have no corners.

Tank 'life'

Although static LPG storage tanks and proprietory gas cylinders ('bottles') have manadatory test periods (Ten years and Fifteen years respectively), Automotive LPG tanks are not subject to these checks. It has been assumed that any Automotive LPG tank will be scrapped along with the vehicle at the end its life, which is Ten years on average. .

90 litre tank fitted inside Jaguar XJ 40 boot


This is a standard cylinder tank (this particular example is a 90 litre tank, 980mm long and 360mm diameter). The cylinder is the most popular choice as it is the cheapest to produce, which is reflected in its purchase price. The cylinder will take up quite a lot of load or boot space (unless the original enclosed Petrol tank is removed to make way for the LPG cylinder ). Cylinder tank capacity can be as little as 25 litres or so right up to 200 litres although (as with all automotive LPG tanks) you must not forget to deduct 20% of the capacity for expansion space. Thus, a 100 litre tank will have an actual capacity of 80 litres.

Cylinder tanks do not have to take up all of your boot or load space .....

Here is a 70 litre (300mm x 1100mm) cylinder sitting snugly in the boot of a Jeep Grand Cherokee. Note that the spare wheel stays mounted its original position (although it has been moved slightly).

Toroidal (Polo mint shaped)

Here is a spare wheel replacement toroidal (doughnut shaped) tank. As its name suggests, it drops into a spare wheel well horizontally, occupying the sunken space provided for the spare. The tank in the picture is designed to take the place of an underslung spare wheel. Some vehicles (e.g. Range Rover) require a vertically mounted spare wheel tank which are also available. The toroidal tank can be a good solution for those wanting to maintain load or boot space. The spare may not be carried at all if the tyres are treated with puncture sealant (either all tyres are treated by a specialist or a can of puncture 'foam' is carried in the vehicle). Although this type of tank has great benefits it can be much more expensive to buy than a cylinder as it is much more difficult to produce.


And here are examples of the underslung tank. They require a lot of ground clearance which is why they are almost completely restricted to off-road or four wheel drive vehicle installations.* Again, they are an efficient way of storing LPG when interior space is at a premium but they are much more expensive to buy. This is partly because two cylinders and mutivalves must be fitted to equal the capacity of an average sized boot mounted cylinder (70 litres) in the form of 2 x 35 litre underslung tanks.

*Note that underslung tanks must have a minimum of 250mm (10") ground clearance. Most saloon cars do not have sufficient height above the ground and cannot have underslung tanks fitted.

Further options

It is possible to remove the petrol tank and replace it with LPG tanks (as done with the Isuzu Trooper in the picture above, showing the underslung tanks fitted) and fit a smaller reserve Petrol tank holding around 5 gallons or so. Reserve Petrol tanks are on the market but very expensive and extremely difficult to fit. Currently they can be bought for 4WD vehicles but little else.


Some owners elect for a combination of some or even all three of the above tank options, e.g. in the case of a Range Rover this might be 2 x underslung and 1 X toroidal, giving a total capacity of some 140 litres. Other combinations can be fitted depending on the application. In the case of any multi-tank option it is normal for all tanks to be fuelled by a single filler point. Similarly, all tanks will supply the engine with fuel simultaneousely. It is normal for only one fuel gauge sensor to be connected to the gauge readout, giving a reasonable picture of the contents of all tanks as they will reduce at the same rate.


It is not possible to make square or oblong LPG tanks out of steel and because of that there are no tanks of that shape on the market.


It is a relatively simple matter to switch tank sizes and shapes once the initial conversion has been carried out.

Many Go LPG! customers start off with a cylinder and later take advantage of our tank part exchange scheme. We will supply and fit a different size or shape tank at preferential labour rates (for our previous conversion customers)* and allow an amount for the secondhand value for the removed tank against the cost of the new installation.

*You do NOT have to be one of our previous customers to take advantage of the tank p/x scheme but our normal labour rates will apply.

Related subjects - 'Is my car more dangerous when it has an LPG tank?
'How do I fill my LPG tank?

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