Water is overflowing 02 gmc

Are you losing any coolant ? Any leaks , heavy steam out of the exhaust ? Fluid level in radiator or overflow reservoir good ? Can you see the fan/fans running ? If fan/fans not running turn AC on and see if they run then. Could be thermostat not opening completely or water pump going bad. Radiator may be clogging slowing circulation.

Are you talking about the ac drain hose ? And is it clear water or coolant ?

Is your upper rad hose hot? Any heat in the car? If not usually the thermostat. More info. Hope its not a headgsket. Any leaks on the ground?

do you have a water temperature gauge in the car-what is it reading-you may also have trapped air in the system-run it-make sure its up to operating temp then let it cool down,about an hour and check the coolant level-it may take a few cycles of warming up and cooling down to get the air out-while you're doing this make sure the overflow bottle has plenty of fluid in it to be sucked in while system cools down-cheers Denny

it is over heating,thermostat stuck close,water pump weak.

when replacing coolant, did you bleed the air from system! you can remove radiator or overflow cap when cold. start vehicle and let it run until thermostat opens,when all air is out hoses should get hot. but before starting, turn heater on to high setting, if you vehicle does not have a air bleeder on it. do as above. just be sure radiator is full of coolant. after hoses get hot, turn off heater, then put cap back on radiator or overflow. good-day! the first thing to do is to check for a stuck closed thermostat. do this first ok!

you may have too much coolant in it... oddly enough,. I've seen entire cooling systems (and even the engine get replaced) and it still over heated -- when in fact it was an all of a sudden the car required a larger radiator -- and the (freaky) problem was fully solved,. in your case it may be a larger holding/ overflow tank?

Best regards
Ck

fuel ijectors will not cause this needs water pump and termostat replaced

P1133 is a slow 02 sensor or a shorted to ground at the PCM to 02 sensor signal. If the 02 sensor does not cycle fast enought it is called a lazy 02 sensor, the only way to test for this is with a digital volt meter or a scanner. if it will not pulse fast enough it will throw the code so Replace the 02 senor on the driver side bank. Bank one. then clear the codes. The code is thrown do to seveal reasons the 02 sensor could be dirty or it just could be worn out, you could pull it and clean it and try it again or just replace it and be done with it. The cost of a heated 02 sensor is $50.00 at a auto parts store or the dealer might charge a little higher but the cost in savings of fuel is well worth it.

check your thermostat and water pump, also check if there is any water or coolant in your rad and overflow bottle at all, rad should be full and overflow bottle should be half full