2018 Equinox has poor heating when the outside temperature is below 10°F when at speed below 30mph or at idle. Above 35-4ph it will cook you out of the car, below 30mph or stopped when the outside air temperature is below 10°F what comes from the vents is lukewarm air. I’m the only owner of this vehicle. Chevy has not been able to fix the problem. Thermostat has been changed twice. Have tried the grill bra, waste of time. And I’m religious about maintenance and keeping fluids up. Chevy answer to the problem is the Ecoboost 1.5L engine is so small it can’t produce enough heat to warm the cabin. I call BS I had a Ford Aspire with a 1.4L engine and that could cook you out of the car. Any suggestions and fixes are welcome.
Doesn't hurt to do a heater core flush. You could also have air in the system when you change the thermostat. Should be a bleed valve on the radiator.
