well i have a 91 crx si w/b16 and last week i blew the coolant hose that loops/connects to the intake manifold. so i replaced it thinking it was all good. well when i got her home the coolant was overflowing in to the overflow reservoir to the point i thought that it was going to explode out. i was thinking that maybe the radiator cap was bad bc of how much it would move, so i replaced it and its still doing the same thing but worst now. the car was NOT overheating at all until i replaced the radiator cap. what else could i check. im thinking that their has to be some sort of blockage somewhere bc the coolant dose not start overflowing until 15-20 min after the car is warmed up. im going to replace the thermostat to see if that helps but i just wanna check if anybody has some other ideas.....thanks

 

water pump or yeah the thermostat

 

An overheated engine prior to coolant overflowing (suggesting exhaust gases are blowing into the cooling system) unfortunately is a symptom that the head gasket did in fact blow.

You can try putting in a new OEM thermostat and new OEM rad cap, but plan for the worst. If you do not go OEM for these parts, all bets are off.