2017 Malibu 1.5 turbo, overheated on me , so the oil change facility put this head gasket block radiator stop leaking in overflow just in case to be preventative maintenance..well it was fine first day, then the next heated up, car went into safe mode low idle, engine cooling fans kicked on and temp began to drop rapidly, then car went back into operational drive mode. I didn't let it do it again, stoped at fuel station immediately, shit off engine, opened hood. Cooling fans ran good 5 more min. There was no boiling in the overflow, but at bottom of resivor could see what looked like sand, the coolant had become like pink Pepto vismol that had not been shaken up, it was grainy. I used the shop vac I had in trunk to suck it out resivor, put hose rite in cap opening created good seal, and it came out like a milk shake through coffee stirring straw. Needless to say, car made it back after filling overflow back up with 50 /50 mix coolant. Drove exactly 6 miles, it didn't heat up until last 3 miles, as I seen the temp gauge rise I accelerated steadily, placed car in neutral and coast doing apex. 50 mph. Through side access road that had some slight slopes, took away speed, then gained speed. Temp ran apex 210, and coolant fans kicked on. It never got into the red zone thank goodness. Normal operation is like 180 + 190. Being in Alabama, that may seem tad warm, but I have had the car since 2017, original owner and have 168 thou miles. Body is in excellent condition, interior is in good shape. So back at the home front I pulled from the fire wall the output hose for heater core, using the shop vac I placed hose in the overflow tank cap opening, and semi induced pressure so that it would flow through engine path and push any of that floating " cement' out, the appearance after all the gurgling and build up noise was that Pepto pink upon expelling from firewall heater core outlet connection from where I had removed hose already. I poured another 1.5 ltr. Of water into resivor and induced with the Vacume again until it was clear. After assembling hoses back and filling resivor overflow, I started car, it got up to operating temp, but blew the outlet hose off, not once, but twice, frustrated at loosing the coolant I stoped piddling with it for the evening. Could the thermostat be stuck ? Water pump ? There no leak or squeal noice coming from the pump, pulley is turning with serpentine belt ? Where is the thermostat ? I can not find any YouTube on 2017 Malibu 1.5 turbo, everything is 2016 2018 2019 2020 or it's Chevy Cruze, nothing on Malibu.....sad I know. Would it be feasible to bypass the heater core first and give that a shot ? I need AC and did read that the heater core is not needed for AC to work, it has separate cooling / radiator, but does utilize same coolant in system ? Will the system burp itself of any traped air ? Getting to radiator cap is 4.5 hour work, it's directly under the front upper portion of the body, the radiator mounting / housing frame, if looking at the engine str8 on, the cap for radiator sits directly below where the drop rod for hood would be locked at when hood is not propped open. Any special hose / clamps to util
ize on the bypass? I plan on flushing heater core be sure not leaking, don't need the heat at moment, least good 5 months. Alabama like Mexico at times. Thank you for allowing me to vent and inquire, least it's not the Malibu blowing off steam....please help, I'm lost on where to begin.