420A Heat blows but doesn’t get very hot

[KalebW22]

My heat in my eclipse will blow kinda warm air, i live in wi so it’s always below 30 out my car will warm up a little but it’s still always cold in there, is this just a heater core or is there other things I should look into before just dropping money and time into a heater core

 

[jesse12345]

Are both heater hoses hot or is just one? If it's just one you could always try flushing the heater core.

 

[spyderdrifter]

Your inside heat is from air blowing through the heater core. If the air is cold, so is your heater core. You might have air pockets somewhere in the cooling system (if you've done any recent work on that system), or a coolant leak. If it's a leak, it may not be an external leak. Check your passenger side floor, see if the carpet is wet. You could also have a clog somewhere in the system and it's now reducing your coolant flow, which will lower the air temp as well.

 

[97egl]

My heat in my eclipse will blow kinda warm air, i live in wi so it’s always below 30 out my car will warm up a little but it’s still always cold in there, is this just a heater core or is there other things I should look into before just dropping money and time into a heater core

Could be the thermostat is stuck open and the engine is not able to get warmed up all the way. This would be my first thing i'd check.

You could also be low on coolant, have an issue with blend door movement, or it could be a plugged heater core but start by verifying that the engine is actually getting hot and the thermostat isnt stuck open.

 

[dwb]

Are your heater hoses hot to the touch when the engine is up to temp?
I'd start by flushing your heater core with a garden hose and see if that helps.

 

[BLACK'98DSM]

Given the modification level of the car, I'd start with removing the upper radiator hose and checking to see if it has a thermostat at all. Many including myself have completely removed the thermostat if the car is going to be run very hard for extended periods of time. It's not at all recommended for a daily driver or something that you expect to have hot heat, but does keep the coolant temp down low while revving to or past redline repeatedly. Once you've verified that there is a thermostat, move on with what everyone else has suggested. Removing the upper radiator hose will spill some fluid, prompting you to pour in fresh new coolant and bleed the system, which may eliminate another issue if there are any air pockets or low fluid level.

This is definitely the first 2G with S2K tail lights that I've seen.

 

[CKOPOCT]

Another possibility - the diverter door. The system has a diverter that changes where the air flows through. If that flapper door is stuck in the half-way position, you'll get a mixture of hot air from the heater core and cold air from the evaporator case. Turning the temp switch and watching the mechanism under the pass side should help you see if things are working mechanically. You should also be able to hear the door moving.

 

[TerminalTalon]

You need to make sure it even gets to operating temp first. I always say center gauge roughly. If it doesn’t even get to that point something is wrong. It could be a lot of things but making sure the thermostat works,the waterpump pumps and things aren’t clogged. If it is the heater core you can plug one end and put CLR in there. Let it sit and flush it. You need to have steady flow out of either end.

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[luv2rallye]

Here in cold Mn it's standard winter practice to keep cardboard in front of 1/2 - 2/3 of the radiator when outside temp is below 40F.