My GMC terrain is over heating, replaced the thermostat and it's still overheats. So after it over heated I felt the coolant hoses and all were hot except one, the one going from the radiator to the thermostat housing, or the lower. My question is what are possible causes for my terrain overheating? I also noticed leakage from under the overflow reservoir.
This suggests that there may not be coolant flowing from the motor to the radiator to be cooled back down after circulating through the engine. The lower hose is also responsible for recirculating the cooled down fluid back into the motor. This also suggests that you may potentially have a clogged radiator.
I would recommend having a professional mechanic, such as one from YourMechanic, come to your location to diagnose your cooling system and suggest any needed repairs.
Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing