2013 Chevy Sonic LT is leaking fluid somewhere but there's no visible leak I have to refill the reservoir almost everyday even when I refill the fluid my heater doesn't work it only works for a few seconds and then it goes straight back to cold I have a 11 month old daughter that I have to drive within this vehicle so I need to figure out something to do to fix it I've already replaced the thermostat about 2-3 months ago I just had to replace valve gasket covers on it because oil was on one of the spark plug I really need to know what I can do to fix it and get it running back up to the way it was running when I got it about 6 months ago. Sorry if something came out wrong I was using talk to text LOL