Overheating Problem - Help!

Got a car here that's overheating. When it's in the garage and running the overflow from the radiator fills up pretty quick, then just starts bubbling. Any idea what this could be? I just filled up the radiator again and ran the engine, still does the same thing. No fluid leaks that I can see.

it could be air in your system,get the warm(a lil')
try opening the bleeder valve & see if any air bubbles come up,
also,when the motors warm,
check & see if the upper radiator hose is hot!
gl

Here's another thing that's weird - when I unplug the lower heater core hose, there is fluid, but the top hose is empty. And so far from what I've seen, it's almost impossible to remove the dash on this car. I'll never own a Mazda after seening this piece of crap and how it's put together. I don't think I'm going to be able to fix this car for him.

are you talking about the mazda 626?
if so,my brother has one,
he already took his interior out & put it back together,
1 clue!
all the interior pops out!

nothing screws on like are 4th gens

I can't get anything off, the plastic around the stereo is screwed on from the other side.

back flush it, pressure check it, throw in a new thermo (cant hurt and cheap). Sounds like somethings clogged up though.

back flush??? how do you do that?