Hi,
If the heater hoses don't get hot, either you have air in the system or it's plugged. If there is air in it and the system worked prior and wasn't opened or driven extremely low on coolant, the question becomes, how did it enter the system. Often times, it is a head gasket allowing compressed air to enter the cooling system. When you checked it, were there any bubbles in the coolant?
Also, I want you to try something. When the engine is cold, remove or loosen one of the heater hoses at the firewall. See if there is coolant coming from the hose. If there is none, have a helper start the engine while you watch to see if there is circulation. If there is none, tighten that hose and remove the other, and do the same thing. One is a supply and one is a return, so you may not see a lot from the return if the supply is plugged.
If you do have flow, with the return hose lose, see if you can bleed air from it. If there is no flow through the heater core, try flushing it to see if that helps. Basically, remove the return hose from the core and the supply line. Then using a garden hose, see if you can get water to flow through the heater core.
Let me know. I attached a general pic below showing what to look for as far as the heater hoses.
Take care,
Joe
Image (Click to make bigger)
Thursday, December 17th, 2020 AT 8:42 PM