[rowtheboat]

My heater isn’t working well. It takes a while to get up to temperature. When it does and starts heating it will only stay warm/hot while the vehicle is moving. When I come to a stop light, it starts to blow cold air and if lingering long enough the temperature gauge starts moving up towards hot. I don’t think it’s the heater core. Could it be just low coolant level or a bad thermostat? Should coolant be a 50/50 of coolant/water? Similarly, was having a problem in Summer with gauge going toward overheating. Any advice is appreciated.

 

[jiantao]

Normally, bad thermostat (if stuck open) will have the opposite effect... over-cooling when driving, and fine when stopped.

Coolant should be 50/50 coolant and water, yes. Most coolants come pre-diluted, so they're already 50/50.

Sounds like you have a bigger issue if you were overheating in the summer. Did you check the coolant level?

 

[robertwards]

My heater isn’t working well. It takes a while to get up to temperature. When it does and starts heating it will only stay warm/hot while the vehicle is moving. When I come to a stop light, it starts to blow cold air and if lingering long enough the temperature gauge starts moving up towards hot. I don’t think it’s the heater core. Could it be just low coolant level or a bad thermostat? Should coolant be a 50/50 of coolant/water? Similarly, was having a problem in Summer with gauge going toward overheating. Any advice is appreciated.

Check if your rad cooling fans are working properly----also your in car temperature sensor could be toast, this could explain the no-heat part but that is assuming the cooling system works properly.