Why is my heater not hot enough

Hi Rendy,

First thing to check is your antifreeze. Make sure the coolant level in your radiator is topped up to the proper level; if it's too low there may not be enough in the system to circulate through the heater core.

After that, there are some mechanical things that can cause your heater to not get hot. There's a temperature regulating valve that controls how much coolant flows through the heater core; if that's broken, disconnected or corroded it may not be opening far enough to let sufficient antifreeze through. Of course, the controls that work that valve could have problems anywhere along the line from the knob itself to the cabling or linkage that actually moves the valve.

You'll want to check the heater hoses inside the engine compartment for any kinks or blockages that are going to keep the coolant out of the heater core as well. If the heater fan isn't blowing, then only the amount of air forced through when the car is moving will got to you, so make sure you've got good airflow from the fan.

Generally there are some baffle doors in most modern cars that allow for mixing air from outside and from the air conditioning evaporator that can get jammed or broken so as to not allow the air to mix properly so those will need to be checked.

Finally, the heater core itself could be congested with rust or contaminant such that it's blocking the proper flow of coolant in exactly the same way a clogged radiator does.

As you can see there's no one single answer to your question and diagnosing the problem means working through them one at a time till you determine where the problem is coming from.