I have a similar problem - here's the thread that describes it: https://honda-tech.com/zerothread?id=776553

Before this happened, I was seeing the coolant filling the overflow reservoir when the car overheated, and it was cured by replacing with a stock thermostat.

I've since removed the head and found the head gasket to be in very good condition, but there was a region on the head where the hot combustion gas burned a very thin gouge into the aluminum head itself, and only into the water jacket. The overheat condition caused by the sticking thermostat directly caused the head to begin leaking.

The problem may well be both the thermostat and the head gasket, but if after making sure the thermostat is done right AND that it's functioning properly, if the problem persists, it's most likely the head is leaking by one mode (head gasket) or another (damaged sealing surface).

BTW, I'm having head p&p'd by Joe Alaniz while it's out - always a good reason to BUILD IT when rebuilding time comes...

 

to check the thermostad start the car and let it run.....make sure the fan comes on and check your lower radiator hose , if its warm than your good to go , if its cold to the touch , thats what it is

 

one more thing to check is the radiator cap

 

yeah, i changed the radiator cap also

 

go check your thermostat like i said , let me know how that goes