Ok so my dad and I are trying to figure out why my heater is not working in my 2006 Pontiac G6 with a 3500 v6 engine.. One problem could be if the water is getting hot enough. We wondering what should the temperature gauge reach in order for it to be hot enough for the Heater to work
If fan blows, but no hot air most likely with 3.5 engine is it could be low on coolant. Heater can’t blow hot air if coolant is not circulating through heater core. Low coolant will trap air in these engines and it will need to be filled and bled out. Coolant has to go uphill (higher than the engine block) through the heater hoses and then back downhill into your heater core inside the car. Perfect spot for air to get trapped. No heater output is usually the first sign of low coolant in these cars. They won’t overheat if they are just a little low.
With that said, if low on coolant you need to find leak. Most likely it’s the water pump or a gasket or a bypass hose (don’t rule out the plastic radiator tanks attached to each side of radiator core). Need to inspect the engine or take to a shop if you are not familiar with this engine family. Low coolant could indicate a more major problem (intake or head gasket) or as simple as water pump seal starting to go.
-All the above info only applies if it’s low on coolant. Even if there is coolant in overflow reservoir, the air bleed procedure needs to be done to ensure no air is trapped.
-As stated by others, make sure the air mode and blend functions switch when you command them from the HVAC control. It could be an electrical or mechanical problem with the heater case or control.
Good Luck!