4 1/2 Le Mans tank capacity & reserve

LagondaV12 · Joined: 31 Jan 2026 Posts: 3 Location: FRANCE, France

After 2 1/2 weeks intensive recommissioning, my newly bought Bentley is running well. Test run fine, and I've now driven from Banstead to Sherborne (Dorset) with no problem. Except the first fill-up revealed the petrol tank leaks from the NS forward mounting (at least not from the bottom!).

It has a Le Mans type fuel tank fitted ... can anyone on here tell me its capacity, and the reserve capacity?

I will be driving it home to France next week and need to schedule my stops for fuel; this information will be a great help!

John Murch · Posted: Mon Aug 24, 2026 5:50 am Post subject:

Welcome to the forum,
I hope you have a lot of fun with your new toy.
Le Mans type tanks seem to come in a variety of sizes, and that the chances of your tank being an original one is slim!
However depending on where you read, the 4 1/2 supercharged cars had a 25 gallon tank as standard (but I doubt that was used first racing), other sources suggest that a LeMans tank was either 40 or 45 gallons, but even larger tanks are known. As for reserve capacity, it will depend totally on the tank builder. Sorry not to be able to be definitive.
John

LagondaV12 · Joined: 31 Jan 2026 Posts: 3 Location: FRANCE, France

Hi John,

Many thanks for the welcome, and your reply. As you say, unlikely to be genuine, and I rather feared sizes might differ.

Annoyingly the speedometer doesn't work and has been sent to Speedy Cables for repair, so I'm having to estimate miles as well as mpg. I've now driven the car enough for the level to be below the leak, so will continue until it needs the reserve tap operated. At least I can see the (inside) bottom of the tank. Hopefully the reserve pipe picks up until practically empty.

Laurence

John Murch · Posted: Mon Aug 24, 2026 10:05 am Post subject:

Interesting that you have a reserve tap, does it operate in similar fashion to that on the 3ltr, ie a tap by the filler neck?

LagondaV12 · Joined: 31 Jan 2026 Posts: 3 Location: FRANCE, France

Hi John.

Here is a photo from the restoration file, the taps are on a block near the O/S of the tank. Identical arrangement on the N/S, but in this case dummy pipework replicating those required for pressurising the tank. Electric pumps so no need for those pipes to be connected.

Couldn't add photos, have sent you an email.

Laurence