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Thread: E36 won't blow hot air

  1. #1
    Join Date
    Feb 2019
    Location
    ca
    Posts
    56
    My Cars
    1998 bmw 328i

    E36 won't blow hot air

    This e36 is my first bimmer and I'm new to diy car projects but I'm willing to do mostly everything myself. I changed the water pump, thermostat, water pump pulley and tensioners and bled the system correctly (I'm guessing I did it correctly because it was blowing hot air). Unfortunately I didn't realize that I didn't tighten the hose tight enough on the thermostat side and there was a huge coolant leak and the car overheated, the hose didn't come completely off but I fixed it when i got home. I'm assumed I needed to rebleed the system so that's what I've been trying to do for the past couple of days but I'm not getting any hot air so I'm not sure what I'm doing wrong. I've been told if the system isn't bled, then it could lead to the car overheating but I've driven it to work and taken it for drives to see if there were any issues and there weren't, no overheating or anything. I'm pretty confused and would appreciate any tips you guys have to offer.

  2. #2
    Join Date
    Jan 2005
    Location
    Japan
    Posts
    54,613
    My Cars
    11/88 E32 750iL+98 E36M3
    Welcome here, thread moved from Forum Software Questions & Suggestion to E36 forum. check this first, DIY-Video-Bleeding-the-air-out-of-the-cooling-system https://www.bimmerforums.com/forum/s...cooling-system
    Last edited by shogun; 02-14-2019 at 06:43 AM.
    Shogun tricks and tips for the E32 series are HERE!

  3. #3
    Join Date
    Dec 2013
    Location
    People's Republic of MD
    Posts
    2,291
    My Cars
    22 doors and 4 tops
    park your car on a steep hill, nose up (steeper the better)
    remove the overflow cap
    fill to the line
    start the engine
    turn the heat on full hot and full fan
    have a mate rev the engine back and forth from idle to 2k (this will suck the coolant into the system)
    continue to top off until the coolant will no longer dip below the line.
    let the engine idle
    put the cap on, allow the engine to reach operating temperature
    release any remaining air from the system with the bleed nipple
    allow the system to completely cool
    remove the overflow cap and top off as needed.

    If all that fails then your heater control valve on the firewall is not opening the plungers to allow for coolant to move. However their default position is open so if they fail coolant will flow. When they fail you will always have coolant flowing to the heater core and thus a hot radio and lack of true AC in the summer.
    Last edited by 66 6; 02-14-2019 at 03:41 PM.

  4. #4
    Join Date
    Feb 2019
    Location
    ca
    Posts
    56
    My Cars
    1998 bmw 328i
    Quote Originally Posted by shogun View Post
    Welcome here, thread moved from Forum Software Questions & Suggestion to E36 forum. check this first, DIY-Video-Bleeding-the-air-out-of-the-cooling-system https://www.bimmerforums.com/forum/s...cooling-system
    This is actually one of the videos I’ve watched, maybe I missed a step though. I’ll try again thank you!

    - - - Updated - - -

    Quote Originally Posted by 66 6 View Post
    park your car on a steep hill, nose up (steeper the better)
    remove the overflow cap
    fill to the line
    start the engine
    turn the heat on full hot and full fan
    have a mate rev the engine back and forth from idle to 2k (this will suck the coolant into the system)
    continue to top off until the coolant will no longer dip below the line.
    let the engine idle
    put the cap on, allow the engine to reach operating temperature
    release any remaining air from the system with the bleed nipple
    allow the system to completely cool
    remove the overflow cap and top off as needed.

    If all that fails then your heater control valve on the firewall is not opening the plungers to allow for coolant to move. However their default position is open so if they fail coolant will flow. When they fail you will always have coolant flowing to the heater core and thus a hot radio and lack of true AC in the summer.
    I’ll be trying this method next, thank you I appreciate the help!

  5. #5
    Join Date
    Dec 2013
    Location
    People's Republic of MD
    Posts
    2,291
    My Cars
    22 doors and 4 tops
    No, Flyfish covered it. I prefer the rev method only as it appears to move more coolant through the system.

    In reality it's probably the hill that helps the most. In fact I often place only the front wheels of the car on a lift and then raise the front until the muffler pipes are almost touching the ground. This along with the rest of the steps seems to clear out the air quickly.

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