I started my GM 350 (330 HO) crate engine today for the second time. After about 20 minutes of running I found coolant leaking around the rear passenger side oil pan flange, right next to the starter. The back of the block around the manifold and heads are dry and none of the freeze plugs or plugs on the side of the block are leaking. I was able to look between the converter and block and the back two freeze plugs are dry. Does anyone have any ideas where the leak could be coming from? It's a small consistent drip that won't stop.

Clint

Could it be a transmission cooler line??

Sure it's not coming from the front of the motor and migrating to the back? It's not unusual for the origin of the leak to be far from the drip. Try tightening water pump, thermostat housing, hoses, retorque intake.

I had a leaking water pump mounting gasket drip on the pan rail and look like a leak at the rear drivers side oil pan flange.

TTFN
Mat