Heat is cold at idle

Discussion in '8G Lancer - General Information' started by cykotic247, Nov 29, 2011.

  1. cykotic247

    cykotic247 New Member

    okay well as the title says during warm-up and at temp while at idle my heat is cold. now when i raise it a couple hundred rpms or even just start driving it blows nice hot air. Now i did already check my coolant level and it was perfect level both in the overflow and the radiator. my only thinking was i either have air somewhere or something is going on with my thermostat. Is there a bleeder valve in our cars? mitsu wants 60 bucks to flush and use "their machine" to make sure they remove the air pockets. any ideas?

    edit: i have a 2009 lancer gts.
     
  2. lancer2quick

    lancer2quick Well-Known Member

    Try this.....
    1) remove rad cap with engine cool.
    2) start car and turn heater on high, full temp
    3) run car at idle until normal operating temp
    4) watch coolant level and add as needed

    What this does is opens the cooling system and lets air out the radiator. Any air pockets that are in the heater core will bleed out after about 10 minutes. To speed up the process, have someone hold high idle (2k-2500k) as you watch coolant level.

    If this does not work, it may be a weak H20 pump or failing thermostat. The description leans more toward this, but try the flush first...it cost less.
     
  3. cykotic247

    cykotic247 New Member

    okay well i did do that first but the coolant level didn't hardly move...not like in past with other vehicles when the thermostat opens. i did notice that the of the two hoses going into the firewall the top one was alot colder than the bottom one. hmm... i don't know. i wish we had a bleeder valve but i guess the cap does the same thing..
     
  4. SoulEater13

    SoulEater13 Well-Known Member

    you could possibly have a clog somewhere in the upper system or it could be at the thermostat location. or a failing thermostat. i dont like to do anything to the radiator myself because its a very sensitive system. i dont wanna fry my engine, so i would say take it into mitsu.
     
  5. bakwoods

    bakwoods Guest

    Bad thermostat usually will also reflect in the temp gauge. Gotta purge the system of air. It's a classic "air in the system" symptom. You gotta "burp" the car. Quite literally speaking.

    To add to Lancer2Quick's tutorial:

    Here is my experience:

    Removed radiator cap while engine was cool.
    Topped off overflow to max level
    Started car up and let it run until the thermostat opened up.
    Water started blooping out the top sporadically (must have been the air that was in there?)
    I then stepped on the gas a little and noticed the water blooping out even more from the radiator and the heater got extremely hot.

    I let off the gas, cold air again

    Anyway.. after each rev I did, I got out, topped off the overflow to the max level and got back in and repeated pressing on the gas until it quit blooping out the radiator as violently as it first did.

    I continued doing all this for a total of about 15-20 mins.

    NOTE: It seems that I had to drive my car a bit to get all the air cycled out fully for the heater to finally start working correctly after I had burped it.
     
  6. 03 ES GUY

    03 ES GUY Well-Known Member

    It's the thermostat. My lancer did the same identical thing. I can't even stress enough how easy the thermos are easy to change. And flush your system while your at it. Seasonal flushing also helps the core

    Sent from my ADR6400L using Tapatalk