The left bolt opening for the thermostat housing is not closed properly and is causing coolant to leak.
I suspect the thermostat seal or thermostat housing has failed. Performing a cooling system pressure test should provide a definitive answer. This test uses dedicated equipment to pressurize the cooling system and pinpoint the leak. I suggest having a professional, such as one from YourMechanic, perform this task for you so that you can get your car safely back on the road.
Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing