Heater won't work but AC blows super cold!

[bpark919]

Hi guys, I found a thread already but it was several years old and I honestly didn't understand most of what was being said. Just like my status says, I'm kind of a noob (just bought my first eclipse!) and a car noob in general. I'm down to learn more about cars, but I was wondering. What would make my heater not work but my ac work? As far as I can tell, my thermostat is in the middle, and my coolant seems fine. Could it be the "heater core"? How would I check that, and how much would that be to replace? thank you!

 

[dsmrollerz90]

Does the fan work?
Check your coolant levels.
What does the heater do?
Check relays.

 

[bpark919]

it blows very slightly lukewarm (i would say tepid), but the air blows out so fast (on max) that its cold by the time it gets to me how do i check relays?

 

[blkgst97]

If the fans are blowing there are no relays that need to be checked. If your coolant level is good then your heater core is probably clogged.

 

[bpark919]

NOOOOOO haha that sounds like a lot of money... are they expensive? or does clogged mean i just have to empty it out? when you say core im thinking like... nuclear reactor core? haha so noob sorry :/

 

[xXEclipse]

when you say core im thinking like... nuclear reactor core?

 

[bpark919]

hahaha i know our cars are not heated by nuclear reactors... but i've been watching too much iron man and stuff hahaha how much is it to replace?

 

[blkgst97]

Think of it like a baby radiator. coolant passes through it. the fan on the back pushes the hot air, get it?

 

[Joseph503]

A new heater core would probably be around $100.
But I believe you could just flush it out (not guaranteed to fix the problem though).

 

[bpark919]

got it! thanks guys. So how would i go about flushing it out? (where is it located, etc.)

 

[Absit]

Why don't you check, double check, read how to do it right, and then verify that your cooling system is filled properly before you go on about this?

 

[Chuck981]

id change the heater core for a new one

 

[Sandman817]

check your upper and lower radiator hoses at operating temperature, both should be hot.

I would purge the system of air and then go from there.

 

[Tanro]

Do you have an aluminum racing radiator? One of the local guys I know is running dual shrouded slim fans, a Fluidyne, and Mishimoto hoses. He has troubled getting his heater to blow out lukewarm air in winter.

If your running low coolant temps your heater core may not be getting warm enough to have any hot air. Just a thought.

 

[Absit]

Do you have an aluminum racing radiator? One of the local guys I know is running dual shrouded slim fans, a Fluidyne, and Mishimoto hoses. He has troubled getting his heater to blow out lukewarm air in winter.

If your running low coolant temps your heater core may not be getting warm enough to have any hot air. Just a thought.

If he's hot enough to get into closed loop, he's hot enough for the heater to work.

 

[AlaskanDsm]

id change the heater core for a new one

Unless you have changed out a heater core... SHHHH

I agree with Absit though. Check everything out first before assuming that it is the heater core. For example making sure that the cable to the temp selector is opening up the passageway for heat to be open 100%. Also, If the heater core really is the issue, I would try flushing it first. I know when my heater core was bad, I started noticing a coolant mist getting on the inside of my windshield friom the defroster.

 

[bpark919]

great! thanks guys. Just found out i got my hours at work severely cut so i have absolutely no money to deal with this problem for now guess it's going to have to wait until next winter

 

[AlaskanDsm]

Sorry to hear bro!

Don't get too down about it though. there are still lots of things you can do with your new "free" time to diagnose the issue so that you can still fix the issue at a later time. You may find that the issue is much simpler than everyone thought and may be just dollars to fix... you never know till you look.

Positive man, gotta think positive. otherwise my car would be in a dumpster by now

 

[bpark919]

Sorry to hear bro!

Don't get too down about it though. there are still lots of things you can do with your new "free" time to diagnose the issue so that you can still fix the issue at a later time. You may find that the issue is much simpler than everyone thought and may be just dollars to fix... you never know till you look.

Positive man, gotta think positive. otherwise my car would be in a dumpster by now

True that thanks for all the encouragement! As a new eclipse owner I knew what I was getting myself into from all the horror stories... but I'm going to make sure my car is properly maintained. Now time to go check the coolant/piping...

 

[Wildside22]

have you chcked it out yet? My brothers car is blowing cold too...he is checking coolant level and the hoses right now .

 

[comsoldier20]

If your heater core is clogged one of your heater hoses should be hot while the other one is cold. drain your coolant system then use a funnel to flow CLR (calcium lime and rust cleaner) into your heater core upper hose. Let it sit then use a hose to try to flush it out. If it is still clogged using compressed air will usually fix it.

 

[needbooost]

I would personaly just replace it. If it gets clogged enough it can leak coolant into your vehicle. Its a PIA to get to it just take your time getting everything apart so it goes back togather.

 

[SunDaeDryVuhh]

your plight reminded me of an issue i had with my subaru, however my issue was the opposite. it would blow hot, but not cold. in the end, the clip that connects to the cable, that actuates the hot/cold gate had broken. the solution was to melt a new hole in the plastic, and reattach the cable. taking apart the dash was the most complex part of the repair.

it can't hurt to see, and could save you the trouble of replacing the heater core.

good luck =]