Harry’s garage car storage ..

[hot66]

Just watching latest Harry’s garage and notice he prefers to store his cars with a full tank of fuel . I’ve always done the opposite and stored with an almost empty tank ... mainly so I don’t end up with a tank full of stale fuel . So which is right , full tank or empty tank ?

[911hillclimber]

I've stored my 911 for 30 odd years from Sept to March outside or inside and never bothered what was in the tank.
Car started first time every March (stock 3.2 engine), so I don't worry. I only removed the batteries if stored outside.

If all Harry's cars are full of fuel then the remote fire risk could become a major affair if a fire started.

TBH, I'm more bothered about flatting the tyres as the 911 has not been driven since Sept 2019 and is unlikely to be driven unless I take the wife shopping and the supermarket is only 1/8 mile away....

[Sam]

The theory is that water vapour forms in the empty bit of the tank and causes corrosion.

Fuel going stale is when the lighter elements evaporate so a full tank helps prevent that too.

Realistically if you’re only storing over winter in a garage then either is fine, but unless you completely drain the tank of all fuel and purge all the vapour then a full tank is better.

[BILLY BEAN]

During cooler or cold weather the water vapour content in the air is very low. Consequently, the likelihood of condensation in a fuel tank is very low. In warmer or hot weather the converse is true. A heated garage would likely increase the level of vapour levels a little.
I store my car with whatever fuel level happens to be in the tank irrespective of the ambient temperature.

[hot66]

both of my porsches have plastic tanks so it was really just the fuel condition ...

I've always been an advocate of running the cars up to temp every few weeks even in winter ... problem is I work on around 20 mile drive for this. No chance of that at the moment

[Sam]

Yeah. That’s another discussion over acidic condensates, warming up a bit makes it worse, you need either the 20 minute drive you mention or just leave it.

The only thing I do over winter is either axle stands or lots of pressure in the tyres.

[911GP]

I’ve been pushing my car a few inches every few weeks to help stop flat spots. No idea if it will work but no harm in trying.

[Barry]

One thing you can do is make sure the last tank-full is non-ethanol fuel, so more likely to be a Super-Unleaded of some flavour.

I always do that, particularly for fuel kept in cans that might not get used for months. The boat often runs on the same single can for a season and that's always Super. Anything that's left at the end of the season gets thrown in whatever petrol car is being run at the time.

[911hillclimber]

Interesting, my old 911 has only run on 97 or better fuel for 30 years, and almost always Shell.

As for flat spot tyres, is it the tread that flattens or the carcase?