Radiator overflow cap came off

I checked under the hood of my '99 Dodge Caravan the other day and found the cap to my coolant overflow compartment snapped off.
Why would it come off?
Is it something to be concerned about?

Thanks
Cl8

change out the radiator cap, it seems it's letting the excess pressure out, hinting that the radiator cap is probably worn

Thanks ricebike, I will look into it,
Cl8

np, hopefully it's just the rad cap... another cause is your head gasket blown & the excess pressure is coming from the engine... going thru your cooling system, and out the overflow...

that can also be checked by pulling the oil dipstick and seeing if your oil is like a milkshake consistency than just regular honey/black colored

hopefully this worse case scenario isn't it

np, hopefully it's just the rad cap... another cause is your head gasket blown & the excess pressure is coming from the engine... going thru your cooling system, and out the overflow...

that can also be checked by pulling the oil dipstick and seeing if your oil is like a milkshake consistency than just regular honey/black colored

hopefully this worse case scenario isn't it

Would my car even run with a blown head gasket?
My engine oil looks like oil, not a milkshake!

It will still run with a blown head gasket, just not very well.

Did you try popping the lid back on and driving around? If it doesn't pop off again, I'd consider it a fluke and wouldn't worry about it.

i agree it may just been a fluke; if the cap fails to hold pressure, you'd also noticed excessive coolant mix spewing out of the resevoir as well

Well I recently checked and the cap hasn't popped off, so maybe it was just a fluke, thanks
cl8