Well it's winter and no better time then to have heater core problems! I have a 2001 limited and noticed the heat isn't coming on when the thermostat is open. Instead it takes a long time and a bunch a "mouse in the dash" type noises before the heater core allows heat to the vents. Is the core shot? Should I try a flush first or do I need to start tearing the dash out? Thanks for the input!
Heater core woes
- Thread starter halloran
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BlackWorksInc
New member
First off your vehicle is a 3rd Gen, not a 5th gen.
I would check coolant level in your vehicle, makes sure there's no leaks if the fluid level is low.
If the fluid level is good and you're system is not low on coolant I believe that 3rd gens have a "heater control valve" located on the firewall going to the heater core. This blocks off the heater core partially when not in use to help warm up the vehicle quicker if I recall correctly. Sometimes they can be a bit clogged up/not working right.
By mouse noises, what exactly do you mean?
flyrv9
New member
Yup the heater control valve or heater switch opens and closes depending on where the hot/cold lever is. It was the only way to control the temp. Some are controled by a cable which can break or be loose at either end. Others are controled by vacuum. The valves can also be frozen in place due to not being used for a few months. Usually when heater cores go bad they start leaking as indicated by a sweet anti-freeze smell and wet passenger floor.
Update
Well an update on the situation. Car overheated last night in Reno on our way back home at 11:30 pm. Was about 18 degrees outside. Heading up there to get the car this morning. Going to bring fluids, new cap, and a cooling system pressure tester. When the vehicle cooled down I noticed the coolant in the radiator was low. So I'm introducing air from some place or something is clogging the system. A blocked heater core wouldn't make the engine overheat though right? Would just blow cold air.
The car is a third gen. By "mouse in the dash" noises I mean just that. It sounds like something is moving around behind the dash. I thought it was fan noise too but when I heard a slight gurgle I figured it was the core.
Well an update on the situation. Car overheated last night in Reno on our way back home at 11:30 pm. Was about 18 degrees outside. Heading up there to get the car this morning. Going to bring fluids, new cap, and a cooling system pressure tester. When the vehicle cooled down I noticed the coolant in the radiator was low. So I'm introducing air from some place or something is clogging the system. A blocked heater core wouldn't make the engine overheat though right? Would just blow cold air.
The car is a third gen. By "mouse in the dash" noises I mean just that. It sounds like something is moving around behind the dash. I thought it was fan noise too but when I heard a slight gurgle I figured it was the core.
Pressure tested the radiator and it was leaking out the passenger side seam some place. Autozone had one made by Spectre (Chinese I assume) so I purchased it and swapped it out. Hot air seems to come on when the thermostat opens now but I'll keep an eye on the heater cores performance... $130 for an entire radiator including the mount brackets. I had to have my old Lincoln's radiator re-cored and it cost $550. I guess the difference is one is aluminum and the other is copper.
