Ive got a 98 civic lx with the factory d16y7. Got a coolant leak but i can't see where. Smoke was coming from behind the motor underneath the intake manifold somewhere. Checked the hoses and no leaks. Got underneath the car but couldn't see where exactly. I recently changed the thermostat and was told there was a valve or something coolant can leak from if its bad or replaced wrong so I took it out and all seemed good. Even replaced it a second time in case the first was defective. Still leaking. Can it be water pump? It doesn't leak right away. I let it run to operating temps and nothing. Seems only to happen when driving and under a load. Drove it to the parts store and it was fine. Next store I parked at there was a small puddle when I backed out of the parking space. Would this happen if it was a head gasket? Appreciate any suggestions.

 

Pressure test the cooling system to see the origin of the leak.