[Blue Bowtie]

Welcome Aboard!

"Warm" and "cool" are relative terms. "Warm" in my area would probably be considered "cold" in some places, like Florida or SoCal. Today it was about "warm" enough to snow. Much cooler and we wouldn't get any.

As for the radiator hoses, the hot coolant leaves the engine via the top radiator hose whenever the thermostat allows it. The lower hose should be cooler, since the radiator is supposed to extract heat from the coolant. Again, these are all relative terms.

If the ambient temperature in your area is below 40ºF, the radiator hoses should have a significant difference in temperature. If both heater core hoses are hot, we can presume that the coolant is being pumped through the core, at least in some volume. If you suspect that the core is clogging, you can reverse the hoses so the coolant flows in teh opposite direction through the core - The core really doesn't care which way it goes.

If the core is being heated, it is also possible that the air control dampers in teh ventilation system are not operating as they should. If the heat/cool door is not closing fully, the hot air from the heater core will be diluted by the cooler air bypassing the core.

If the car has a temperature gauge, there may not be numbers, but there should at least be markings. If the temperature registers at least 1/3 of scale on the gauge, the coolant should be hot enough to make heat for the passenger compartment.

Another piece of information which might be helpful is the temperature rating of the thermostat you installed. AFAIK, the stock rating for both L99s and LT1s is 185º (not 195º). Anything lower than that could be contributing to the problem.