Bad fuel petrol / gas life span ?

GREG · #1 (**permalink**) 20-03-14, 11:38 PM

How long for fuel to go bad in a car that's being stored ?

Should it always be drained if in storage for a few months or will a gallon or two of fresh fuel on top save what's left to just run it through the system ?

I have noticed the 6 cylinder Bristols really hate old fuel .. But soon recover with fresh fuel and a carb clean.

peterg · #2 (**permalink**) 21-03-14, 10:55 AM

My 403 was laid up for two years with half a tank of fuel. I had no problems with the fuel going bad. However, during that time mould grew in the base of the tank and it blocked up the fuel line at the elbow above the tank.

Not having the facilities to drop the tank and clean it out I resorted to a bottle of Forte and a large VW filter in the boot, which also gave me access to the lifting pipe and blow it through when it blocked. Hopefully it has cleared and no further problems will be encountered (we shall see!).

GREG · #3 (**permalink**) 21-03-14, 05:50 PM

Yep - it seems this modern fuel can clog things up fairly quick ! I noticed the carbs had gummed up too , but the old trick of the palm of the hand over each carb whilst revving the engine soon clears any blockage

I guess the answer is to just keep driving them !

Ronald G. Stephenson · #4 (**permalink**) 21-03-14, 08:54 PM

I would say a month, tops. Today's fuel is full of stuff that will separate rather quickly, and I am as guilty as most with my twelve cars. Lazy, I guess, but I just know problems will arise and usually disconnect the fuel line at the carb and switch on the pump, or attach an electric at that end. Fuel is expensive, but old fuel is bad news. Drain it and start fresh. Speaking from lots of experience.

Kevin H · #5 (**permalink**) 21-03-14, 11:47 PM

I leave fuel in my car for months on end and don't have any problems. It's usually Shell PULP, 98 RON. This used to be called Optimax in Australia, which used to go off after a few months, but it seems they fixed it up.

If you think about it, if petrol went off after only a month their would be lots of cars in long term car and parks that wouldn't start. That certainly doesn't happen here in Australia.

GREG · #6 (**permalink**) 22-03-14, 02:13 PM

I think the problem I had was possibly caused by using fuel from an old jerry can laid around the garage that looked identical to one I had recently filled ! I will use a marker pen and write on when filled in future -- and get someone to sniff it when I have a cold :-)

Lucky I have a waste oil heater in the garage so nothing wasted !