Homda accord lx 94

Is is usual for the radiator coolant holding tank to overflow? I filled it to the top level, and screwed down the cap. I drove it for around 5 miles, and then I switched the engine off. I heard this gurgling and bubbling sound, and I saw that my holding tank was overflowing. What could be wrong here?

BTW Can somebody please tell me where the thermostat is? I looked into the 2 bolt flange on the approx 2" hose coming off the radiator, and there was nothing in there. No Thermostat. Is it located somewhere else??

My cooling system has a leak or problem somewhere. Ever since I replaced the radiator, it has never worked perfectly.

 

The thermostat is located where the lower radiator hose connects to the engine. The thermostat housing has a bleed valve on it and also a coolant temp sensor on it.

When you refilled your coolant, did you bleed the air from the system? That could cause all kinds of strange problems.