Hi i posted a while back about having heater issues in my 1992 loyale. So i put the oem thermostat in and in made quite the difference my cars temp barley got above the operating temp now it gets to almost halfway on the gauge. So the heater works a little bit better but its still not hot... now im looking for input on where to look next, maybe heater core? it gets warm (keep in mind its 4 degrees where i am.) but just not hot. thanks!

If the engine is at normal temp-  Heater core coolant flow partially blocked, or something with the blend door / mice bringing crap in and blocking air flow.

If you bring the car up to temp, turn heater full blast. Is it significantly hotter when you Rev the engine to 2500 vs idle? The heater core can get clogged with scale. Let it cool, the disconnect the coolant lines that go to the firewall such that the hoses connect to the firewall but you can still hook a hose. A pulse of air or water on the intake hose followed by a flush usually cleans this up enough to allow the heater core to work better.

Double core radiators run cooler than single core radiators and are hard to bring the heating air up in the Idaho winters.  You might block off a portion of your radiator, so that air is not flowing through it, in order to increase the heating air temperatures.  Tie a piece of plywood in front of the radiator and behind the grill.

Sorry took so long to get back but I got a new thermostat now the car heats up.... but if I leave the heater off than turn it on full blast it's hot for one second then cold again

Probably still air trapped in the system...

 

Jack up the front or park on a steep hill or ramps whatever the case -the radiator neck needs to be Higher than the Heater core- run the rpms up to alteast 2,000 and keep squeezing the top hose a little bit at a time until the coolant drops... when it gets up to normal operating temp:thermostat starts to open; you may have to rhis episode a couple hundred thousand times 'Just kidding' fill up the radiator slowly lower rpms to about 1,000 if and when it stops belching air past the fluid you should be full..put the cap on, fill recovery tank to full, ya dont want air getting back in the system and you should be good = that's what I did/do...

perhaps your radiator is clogging up.. I only say that because I bought a junkyard radiator it worked fairly well for the winter and put out minimum heat.. but when the summer came... I had overheating issues plus it bad bad bad for the water pump!

Make sure both hoses going to the heater core are hot. If they aren't, the heater core could be partially clogged.