In less than a month, I've managed to blow two thermostats during day to day driving. This is on a b18b in a 94 cx. I'm using the civic radiator and gsr radiator hoses. The first time this happened, there was massive amounts of pressure built up inside the rad hoses and they started spraying coolant out of the ends. This time, the hose pressure is normal. What could cause this, and is there anything else I should be checking after I change the thermostat? I'm gonna pick up some watter wetter this time around now that its getting warm out again.

 

Are you sure it is the thermostat? If the hoses and radiator were hot, it's opening. If the hoses had all that pressure, I think it was open. Is the civic rad you have one of the half width ones? If it is, there is probably just not enough cooling area. The integras have a much larger rad for a good reason. Honda did not put it there just to cause they thought it looked nice but because they found it was needed.

If it is a full size rad, check pressure cap, make sure the rad or passages in the engine are not blocked. A pressure flush may be a good idea. Any idea how old the water pump is? It's not unheard of for the vanes in the pump to wear or break, reducing pumping ability and partially blocking flow.

 

Pressure flush should definitely be in line.

You might have some issues with your water pump. That's very odd that the thermostat would do that.

Make sure there is good flow thru out the heater core, radiator and the water pump is working properly.