UIM failure will cause coolant in the TB. Better check your oil ASAP. If it doesn't look right (coolant mixing in) you have a very serious problem on your hands. If this is true, you should drain your oil ASAP before it costs you your entire motor.
The only other route of entry for coolant in the TB is a leak at the TB gasket, which isn't as common as the EGR passage erosion in the UIM. Both can cost you a motor.