I was driving my Galant when I noticed the temp gauge fluctuating very sudden (going up and down). I thought it was the thermostat so I changed it but the car is still running really hot. I was thinking about flushing the radiator out again (last time the antifreeze was a rusty color)and flushing out the heater core hoses. When the engine gets hot, the lower radiator hose stays cold. Also sometimes my heat doesn't work in the car. Sometimes it comes out cold. When I turn the dial back abd forth from cold to hot it makes a noise coming from underneath the dashboard. What could it possibly be? Heater core? Water pump? Bad radiator cap? Please help!!! Thank you.

 

sounds like you have 2 problems. first, if you changed out the thermostate and the coolant was rust color, that means the the coolant was non existant and it was pure water and the metal in the engine block is rusting and has probably clogged up your radiator. the radiator will have to be taken out and sent to a radiator shop to be rodded out to unclog it. gonna have to still flush out the block . recommend replacing radiator hoses be replaced at this time if havent already. should take care of that. second, your no heat problem inside and noise behind dash is caused by a faulty heater control valve. gonna have to remove portion of dash around radio and glove box area. be careful when doing this job, tight spot and could break a few things.

 

Thank you for your help.

 

good luck!!