Oops, it doesn't look like 'radiator day' is a national day..

Other days

bow tie

Bow Tie Day
youth

Youth Day
fiancee

Fiancee Day
one

One Day
self care

Self Care Day
frozen yogurt

Frozen Yogurt Day
unicorn

Unicorn Day
hiv awareness

Hiv Awareness Day
hot chocolate

Hot Chocolate Day
lash

Lash Day