Corrosion in Fuel Tank Question V6 Petrol/LPG

[apole]

Hi again,

Got a question I'm not sure about.

I have a V6 petrol with an LPG conversion.

Because of this the car runs mainly on LPG, although they always start from cold on petrol.

I therefore don't use much petrol, and due to the weight and the fact that petrol goes off after a while I only keep less than half a tank of petrol, unless I have a long journey that means I don't have to stop if I fill up both tanks.

My question is if I continue not to have the petrol tank full, will the upper part of the tank go rusty? if so would I be better to keep it full and how long does petrol last before it starts to degrade?

[dandywarhol]

I find significant degradation after around 6 months - you can usually tell by smell - it smells vile!

[Dolly1]

Hi Apole,
Squirt in some Redex, that should do the business.

[francophile1947]

how long does petrol last before it starts to degrade?

Depends on how it's stored and if there is a vent to the outside. The petrol in my lawnmower has been as flammable as water after only two months.

[mikeonb4c]

Well well, I never knew that! I would think then that - all round, the fuller you kept the tank the better so that (a) there was less free volume above the fuel for moisture bearing air to occupy and then facilitate transfer of moisure into the petrol and (b) chances of corrosion to the upper tank are reduced for much the same reason.

I'm off to do a bit of googling on this as it sounds weird!

[apole]

It's an odd question but I just don't know what is best, 70 litres of fuel would take a long time to burn so it could go off, plus it's alot of weight to lugg around.

However in my distant youth I had an old VW beetle that was restored, and it kept breaking down with a blocked carb/fuel filter. Turns out the uppermost part of the petrol tank was rusty, just the top, rest was fine.

Modern cars tend to have plastic tanks, and diesels don't suffer at the top so much as it's an oil, however as oil floats on water could that mean the bottom of the tank could rust if condensation gets in?

I could have started something I regret in which case I apologise !! It's been a very long week.

[mikeonb4c]

It's an odd question but I just don't know what is best, 70 litres of fuel would take a long time to burn so it could go off, plus it's alot of weight to lugg around.

However in my distant youth I had an old VW beetle that was restored, and it kept breaking down with a blocked carb/fuel filter. Turns out the uppermost part of the petrol tank was rusty, just the top, rest was fine.

Modern cars tend to have plastic tanks, and diesels don't suffer at the top so much as it's an oil, however as oil floats on water could that mean the bottom of the tank could rust if condensation gets in?

I could have started something I regret in which case I apologise !! It's been a very long week.

I'd keep it topped up as - once in a steady state - the fuel will be getting used up at the same rate whether the tank is full or half empty. If bothered, you could always run on petrol at intervals to deliberately purge the contents. You don't want condensation in the tank, that's the main thing I reckon, and the fuller it is the less there should be. The weight penalty thing is a judgement you have to make - more weight may be the price of more insurance. On the plus side, you are carrying better insurance too against any trip where you find there is no LPG station for miles.

[New Forest Terrier]

I had a rusted petrol tank on my old LPG converted Range Rover. This problem showed up three years after the conversion, but at the time no one put the two together and I just replaced the tank.

Mine was just like the Bongo, started on petrol and ran on gas. I kept about a quarter of a tank of petrol, which needed topping up about every month. The only time I filled the petrol tank was once or twice a year as insurance on long journeys.

The tank failure may or not have been to the lack of petrol. The Rangie was eight years old when I bought it and the culprit could be time and Hampshire mud.

[The Great Pretender]

What you lose and lose fairly quick are the lighter hydrocarbons in the fuel, so octane rating drops. As your petrol is only used until the engine is hot enough for your evaporator to work your only using a light load on the engine so that shouldn't be a problem.

[cheffy34]

When are you doing my conversion TGP i'm getting bored of waiting while your at it do me seals


Dar

[The Great Pretender]

When are you doing my conversion TGP i'm getting bored of waiting while your at it do me seals


Dar

Waiting for your signed blank cheque to arrive................

[cheffy34]

When are you doing my conversion TGP i'm getting bored of waiting while your at it do me seals


Dar

Waiting for your signed blank cheque to arrive................

A handshake and a kiss wont work then treacle

[cheffy34]

Oh by the way for a blank check i want your v8 in it and no gas

[The Great Pretender]

Oh by the way for a blank check i want your v8 in it and no gas

No problems......................as soon as I cash it you get 2 more cylinders.

[cheffy34]

Oh by the way for a blank check i want your v8 in it and no gas

No problems......................as soon as I cash it you get 2 more cylinders.

What cylinders