I have a 10 liter canister filled with diesel in the trunk of my 1.6 TDI Octavia.

 

I had it filled once, then I used the fuel and left the cannister closed in the car. There was some small amount of diesel left inside.

 

After 3-4 weeks I wanted to fill the canister again. I opened the canister, TSSSS, a short, distinct hissing sound. Like I opened a soda. 

 

Is this normal or is it the possible that the diesel leftover has somehow gone bad in less than a month?

Edited 8 May, 20242 yr by KingJ

Probably just the fuel and air in the can expanding with the temperature. The cans are designed to be airtight and expand and contract, so it's nothing to worry about.