Spring a leak
Definition 1 of 2
Pro Tip 1/3Literal Meaning
Most directly refers to physical containers or systems leaking liquids or gases. 
The inflatable pool sprung a leak after it was punctured.
Pro Tip 2/3Urgency Implication
Implies an unexpected problem that needs immediate attention. 
We must fix the radiator that sprung a leak before the workshop floods.
Pro Tip 3/3Emphasize Problem
Used to highlight that something is not functioning correctly. 
The new pipeline has already sprung a leak.