Mother’s car, 2001 Plymouth Neon.
AC will cool the air.
Blower blows fine.
Air direction works (feet, upper, blends, etc)
But when she wants heat, it just acts like the vent.
It is very possible that the heater core is blocked with rusty debris.
When was the last time that the cooling system was flushed?
When was the last time that the coolant was replaced?
With engine running and heat ON, carefully feel both heater hoses (the 1" hoses going to and from the firewall). If one is hot and the other just warm, the coolant isn’t getting through the heater core.
Im quite a novice.
Firewall and heater core are words over my head. Haha
Even if you are a novice, you could check your maintenance invoices in order to answer the questions that I posed earlier:
When was the last time that the cooling system was flushed?
When was the last time that the coolant was replaced?
Firewall=the metal partition separating the engine compartment from the passenger cabin.
Locate the two 1" diameter hoses running from the engine to the firewall (probably closer to the passenger side of the vehicle than the driver’s side), and do what insightful suggested in order to determine if–as we both suspect–there is a blockage in the heater core.
Is the coolant level correct?
Is the engine getting up to proper operating temperature . . . is the needle getting to the 1/2 - 2/3 mark, for example . . . ?
You might be right, just a vent door problem like you speculate. But try to address the questions posed above, that will get you to the solution faster probably.
It’s a little murky as to whether the air flow is coming out of the proper registers or not, IMO
First Thing!
As @db4690 has recommended, the coolant (anti-freeze solution) level in the coolant reservoir and the radiator (if it has its own cap) needs to be checked when the car is COLD For Safety Reasons (burns from hot liquid).
If this car is low on coolant (a possible cause of “no heat”) then engine damage could occur, if it hasn’t already. Also, be aware that the temperature gauge/light may not work properly to warn of overheating if the coolant is too low. And believe it or not, the engine can be over-heating when in fact there is no heat available for passenger comfort.
Do Not run this car until you check!
Check it/get it checked and come on back and let us know what you find.
CSA
I believe that vintage Neon had frequent headgasket problems.
I believe that vintage Neon had frequent headgasket problems.
That is a myth, any (water cooled) car engine can develop a head gasket failure if driven without coolant. This engine has a multi-layered steel head gasket that is just as durable as others.