Heater core?

[ChaseR]

Ok so My heat doesn't seem to be working, every once in awhile I notice the temp pick up for a bit but then it goes away quickly. Most of the time there is no temperature change even with the fan on full blast. Any ideas as to what could be the problem? heater core bad maybe? or should I just do a good cooling system flush?

[codyJDM]

Same problem, and I flushed my cooling system maybe 3 weeks ago and made no difference. I think it's my heater core.

[2oodoor]

sounds like the thermostat to me

[nswst8]

There is a valve on the heater hose just before the fire wall, this divert the coolant away from the heater core when not in use. ensure this valve is operating properly. The cable could need minor adjustment or have come off entirely.

[nswst8]

This cable attaches to the air mixture lever at the bottom right of the heater unit. Check thse attachments.

[nswst8]

Ok so My heat doesn't seem to be working, every once in awhile I notice the temp pick up for a bit but then it goes away quickly. Most of the time there is no temperature change even with the fan on full blast. Any ideas as to what could be the problem? heater core bad maybe? or should I just do a good cooling system flush?

You need to replace the thermostat ASAP.

[Dr_Snooz]

I used Alumaseal in my radiator once and my heater stopped working after that. I think it sealed up the heater core better than it did the holes in my radiator.

?!?!?!

[ChaseR]

Its a brand new thermostat! I replaced it when I rebuilt the engine.

[nswst8]

If the temp starts to spike then all of the sudden drops to normal. I would suspect bad/faulty thermostat. Air in the system.

My dad had a Plymouth Acclaim that you could only put an OEM thermostat in. Use anything else and it would do the exact same thing you described, then blow the head gasket. I had to replace the head gasket for him twice. We could watch the temp gauge climb with a aftermarket but as soon as I put in a OEM you could see exactly where the thermostat opened and closed.

Could be air or a faulty thermostat. The only aftermarket I would consider putting in these accords is a failsafe thermostat.

[nswst8]

Did you put the heater valve cable back on the valve body?

[2oodoor]

is the temp guage operating in the same range as usual? I read the first post thinking temperature change meant on the guage,you must mean air tem in the cabin.
check the coolant level, bleed air out, and see if it makes any difference by moving to defroster, panel, floor, a couple of times.
Also if you have done any radio changes you may have unhooked something or moved something in the dash.

last but not least, new thermostats fail too, but check everything else we said....and make sure your radiator fans do not stay on all the time, that is not good in the cool weather.

[ChaseR]

Well I have tried everything, looks like im taking apart the dash to replace the core.

[Dr_Snooz]

Before you get that drastic, check that your fan doors are not malfunctioning. Could be a problem with your control switches or the solenoids that operate the doors inside the dash to redirect air.

I always thought heater cores failed by dumping coolant all over your floorboard, but maybe not.

[russiankid]

Sounds like you have a big air pocket.

[lostforawhile]

are you sure the thermostat isn't in facing the wrong way?

[ChaseR]

Yes I am certain of that. It only fits one way.

[Toneloc5145]

Try the easiest and cheapest way of fixing it first. I would make sure you have enough coolant, bleed the system, and if that doesn't work, change the thermostat. I had to do that 2 weeks ago because my heater wasn't working either, and those steps solved the problem.

[ChaseR]

Yeah man I have topped off the cooland and changed the thermostat. It has to either be the valve or the core.

[evil88accordLX]

seem ironic you are worried about heat living in El Paso!

[ChaseR]

it still gets cold as fuck here, in fact let Me tell you the coldest I ever think I have been was in Iraq.. Don't be fooled the desert gets cold as fuck and I grew up in flagstaff Arizona.

[lostforawhile]

he's correct, at night theres nothing to hold the heat there at all, so it all radiatates out and disapates into the air.

[2oodoor]

valve is a hella lot easy to get to on the firewall, the shaft in those can break or freeze.
You can try removing both heater hoses from the core out there too and try flushing it with a gardon hose.
This would be a good time to use an infrared thermometer to see the temp on those hoses in and out.

Also if the engine fans run too much it really cuts the temp down for winter.. not good