I have an 02 duramax and it started leaking coolant this weekend. It didn't leak at all before this weekend. Its filling the engine valley then running down the backside of the block. It'll leak pretty good once up to running temp and after shut off. It doesn't look like its coming from the thermostat housing anywhere. I'm wondering what all is back farther that could leak. thanks for any input.

 

Turbo coolant line?