Longman Dictionary of Contemporary English
Wiktionary
n. The cap that closes the opening of a tank, e.g. the fuel tank of car, from which the tank can be filled.
Usage examples of "filler cap".
It was leaking gasoline out the filler cap, but Cortez reached in and got his cellular phone.
The hood squeaked when she raised it, but she made herself reach out calmly to the oil filler cap on the manifold of the slant-six engine and twist it off.
Steam was hissing from the filler cap under the sun goddess, and oil was streaking from the louvers of the hood.
He took a new half-gallon can from a rack, punched a pouring spout into its top, and brought it back to the tractor, where he took off the filler cap and up-ended the can over the transmission.
Pre-cut holes in one side were matched up with the pipe that would terminate at the filler cap—.
There were fresh scratches on the paint round the chrome petrol filler cap, and clusters of small white grains.
As soon as it had washed the salt from the deck I blocked the scuppers and opened the filler cap to the fresh water tank and let it run full.
I twisted the inflow, unscrewed the filler cap, waited for the pressurized nitrogen to hiss out, and then dumped in the jug of phage.
I removed the nozzle from the Cherokee's tank, closed the filler cap, hung up the hose, and went back to stand beside Jim.
He unscrewed the filler cap and lowered the handkerchief down so that it must reach the bottom of the tank.
By the light of a hand-dynamo torch I managed to locate the filler cap and poured a quart or more of honey into the tank.