1999 no heat?

[cjben]

My son has a 1999 galant. The heat will only blow warm for a couple seconds,then goes cold or lukewarm. I replaced the thermostat and that didn't help at all. Would it be the heater core? I noticed one hose is hot and the other is barely warm on the heater core after the car has been running for a long time. Would it help to flush the heater core? How hard would that be? the heater core isn't leaking but I guess it still could be not working properly? This is my son's first car. He loves it besides the fact it's getting cold here and heat would be GREAT Thanks for any help!!

[FooseGalant]

Hello cjben,
I had a heater core failure on my 2000 Galant V6. Not a nice job having to remove the entire dash from the car to get it out. I would suggest flushing the core first if it is not leaking. The inlet and outlet ports are on the firewall inside the engine bay under the intake and EGR valve. drain the radiator and remove the hosed from the bulkhead connector and flush both. Watch the pressure so you don't stress a worn core and cause a leak. Reverse the flush if you do not get sufficient flow on the first attempt. If that does not fix it, the next step is checking the temp control. Let us know how you make out.

[cjben]

I have had time to do more research on this problem. seems the control motor/valve under the dash is a big failure point on these cars. Is there any way to determine if this is the problem before I buy the part and it wasn't the problem. I guess the cheaper route would be to flush the heater core and see if that fixes the problem. I just don't have a lot of time to work on it. We both work different hours and it's getting colder here.

[deeznutz]

99-01 didn't have the control motor its cable!!! If one hose is hot and the other is warm there is a blockage or the cable is screwed up your not getting complete full flow

[kylecanthurdle]

let that thing run with the front wheels suspended with the rad cap off and the heat on high. if you can, go to harbor freight and buy a cheap laser thermometer and shoot the thermostat housing and make sure its getting up to 190-200 degrees F. put a funnel on the rad where you took the cap off and keep topping it off until the rad fan turns on a few times.

[cjben]

I do believe it is getting as hot as it is going to get. We drove to the town he lives in(25 miles away) at 75 mph and both the top and bottom radiator hoses were hot and weren't under a lot of pressure.

[kylecanthurdle]

does it get warm when you rev it up? i had a problem with a customers galant where the car would blow warm when you were driving but when you came to stop and let it idle for a little bit it would get cold and it was a faulty head gasket.

[cjben]

no,it doesn't get warm ever. Idling,when you rev it up,never. I am going to try to flush the heater core out and see if that helps the next time I have time to work on it. One of the heater hoses is cold and the other is hot even after the car has ran 25 minutes at 75 mph. I did change the thermostat and now both the top and bottom radiator hoses are hot after it runs awhile. Is anyone sure this year car had the cables instead of the control motor/valve?

[kylecanthurdle]

the cables from your heater control go right to the heater box. try to crawl under the dash and find where the cable connects to it and see its its actually moving. i dont think its possible but you may need to see if the blend door is moving. maybe its just stuck on cold. ideally if both of the heater hoses are hot that means youre getting hot water flowing through the core so i doubt you have a restriction. (although it wont hurt to shoot some water both directions and see if there is any restriction)