Overheating problems with 1994 Honda Passport

I've had previous problems with my Passport but it didn't really start getting bad until I had to replace my radiator. I got a new radiator (single core where the stock radiator was double core)and installed it but it was still overheating. I took out the thermostat (which was stuck shut) and left it out because my step-dad being the back yard mechanic he is said that it only needs the thermostat when its cold out (will replace anyway), but that didn't help. I called around my town to see if any mechanic might know what the problem is and one of them said that there might be air in the coolant system and he said to bleed it. The car will stay below the half-way mark on the temp gauge while idling and for a while driving but after about 10-15 miles it starts to climb and overheat again. My question is can anyone tell me where to locate the coolant bleed or give me any more advice on how to fix this problem. Its my only car and I don't have a lot of cash and the thing is kinda beat up. plz plz i need help. This car is my life line.

There is no coolant bleeder. Doesn't need one. The only time these are needed are on some cars where the top of the radiator is lower than the top of the engine. Put a new thermostat in now. Running without one is not a good idea. Your shade-tree mechanic step-dad is wrong. Thermostats are needed in any weather. The thermostat acts as a flow regulator and it is entirely possible for an engine to overheat BECAUSE of a lack of a thermostat. Get a stock replacement radiator. Running a single core in place of a double core is like putting in half of a radiator. When filling, squeeze the hoses gently to get any air pockets out.

the person i got the radiator from said that the single core was the only one they could sell me because it was made of aluminum and not copper because the price of copper is so high and he also said that they didn't manufacture radiators with more then one core for the 1994 passport anymore. I also talked to some people on AF community chat and they said it might be the head gasket as well. *sigh. I need to get a pressure test also, right?