Can't get the block coolant plug out, can I remove the CTS to drain instead?

[Jerry]

Hi guys, I tried and failed to get the coolant block plug out, I ground down a 3/8" square drive to fit but it snapped off in the hole and I can't get it out now! :(

Oh why couldn't they have made it a standard drive size!!

 

I pulled out the coolant temp sensor hoping I could drain it through that instead but nothing came out.

Is that normal or is my system clogged? I don't have any overheating issues so I'm hoping that's not the case.

 

Thanks for your input in advance :)