How long before gas contamination

[Walter F.]

I have been watching my neighbors C3 which went under a car cover last summer and has not been started or moved since. How long does it take for gas to go bad in the tank is left outdoors in winter and summer untouched.

[Michael W.]

Re: How long before gas contamination

Years......

[Duke W.]

Re: How long before gas contamination

It depends. If it's a model with an evaporative emission system the fuel system is somewhat "sealed" except the carburetor, and this will slow the rate of moisture absorption by the fuel system, especially if the fuel tank is full. If it's near empty degradation will start sooner.

It sounds like this car was just "parked" rather than being prepared for long term or indefinite storage, but outside storage will cause a higher rate of degradation of all systems than if the car was properly prepared for storage and kept indoors out of condensing humidity.

Pressure/temperature changes cause moisture to take a one way trip into the fuel system, and it's worse in a vented system. At night temperature drops, which causes lower pressure and damp air migrates into the fuel system and then condenses to liquid water. It's a one way trip. Once water vapor condenses in the fuel system it's there to stay.

Outside "storage" in a damp climate without proper preparation will usually mean significant damage in as little as a couple of years.

Duke

[John D.]

Re: How long before gas contamination

No way will ethanol last years on a car stored outdoors. Wish it were true though.

[John D.]

Re: How long before gas contamination

I know two years is ok because i just started my 67 small block after sitting that long in a unheated garage. Had a DIY home renovation project that kept me busy...

[Duke W.]

Re: How long before gas contamination

Any garage, including unheated, is ten times better than sitting outside.

Duke

[Jack H.]

Re: How long before gas contamination

I would also suggest that there's a big difference between gas that's good enough to start a car, and gas that's any good. Leaving deposits and coagulated crap in the fuel systems would also be a concern to me.