We went for about a 45-minute drive in our 98 V70 today. Then the car sat for about 2 hours. When I got back in and cranked it, the "coolant level low" light comes on, so I shut off the engine and popped the hood. Looking under the hood, I noticed that the expansion tank was dripping wet and the cap has a good-sized horizontal crack in it that definitely wasn't there before.

The last time I changed the coolant (a couple of months ago), I think I might have put too much coolant back in the expansion tank. Seems like the coolant level was somewhat above the MAX line. Could that have blown the expansion tank cap or should I be worried that something else might be wrong?

Thanks!

 

The bottle might be cracked as well. So you might have a cracked bottle and cracked cap.
I cannot see the coolant level going that high in the bottle to leak that much and be low enough to make the light come on.