Cooling Problems! 91 Honda Accord
 

I have a 91 honda accord and recently I noticed my gas mileage has
dropped quite significantly. My temperature guage has been reading
slightly lower than normal and seems to fluctuate and drop frequently.
It has also overheated once or twice on me during the past two weeks.
I changed the thermostat and drained the coolant but still no change.
The lower radiator hose is extremely cold and the top one hot. I
havent noticed any coolant loss and i dont see any coolant flow with
the radiator cap off and the engine running. I am completely stumped
anyone have any ideas on what might be wrong? Thank you!