New car, new issues..

Discussion in 'Chevy Express Forum (GMC Savana)' started by Kelmannen, Nov 15, 2013.

  1. Kelmannen

    Kelmannen Member

    Hello evereyone!

    I recently bought myself a Savana conversion -2003 and now when it gets cold i cant get heat from the front heater, the rear heater works fine but not the front one, first i thought i was iar i the heater (and it was!) i managend to bleed it and the air got a little bit warmer, but nowhere near hot.

    Today when i was turning the dials for the heating i notice that even tho the fan doesn't change speed the airflow drops radically when i go from cold to hot on the dial, so guess there is some port/actuator thats not opening!
    i found something on a site (gmparts east) which i think is the failing part, but it would be wery nice to hear if someone had the same problem and solved it?
    All the different modes work, no problem with changing modes, it just drops all airflow when i turn the dial on red! (exceps for the rear heater which gives a lot of heat so that makes it for nothing wrong with the dial, it's the same dial for both front and back heater)

    heater-asm-tx08006801 värmepaket fram.jpg
    i think the failin part is number 21 (marked with red circle) it's name is "ACTUATOR TEMP VLV,(INCLS BRACKET & CAM)" so i guess thats the one controlling the temperature.

    Iwould like to know if there is a way to test it so that i know if it works (if the controller/relay doesn't) or if it's broken.

    Last edited: Nov 17, 2013
  2. RayVoy

    RayVoy Well-Known Member 2 Years 1000 Posts

    The first thing I would do, is make sure the engine coolant is moving through the heater core. Under the hood, find the two hoses going to the heater. Both should be hot.

    If both are hot, the core is letting the fluid flow freely and there should be lots of heat available inside the cab. To get it to the passenger area, the blower air must pass through the core and be able to exit a vent.

    So, does the blower appear to be blowing sufficient air?
    - can you change the blower speeds?

    If blower appears good, then the air mixture door (temperature) may not be working. On your truck, the door is moved by a small electric motor called an actuator (the part you identified in the drawing).

    You should be able to hear it operating. Engine off, but key on, moving the temp control should produce enough movement for you to hear it.

    If it sounds like it moves, you might be able to reset the actuator. Try pulling the HVAC fuses (or just disconnect the battery) and the darn motor may reset it'self.
  3. Kelmannen

    Kelmannen Member

    thank you RayVoy
    Yes i've checked the hoses and they're hot and i can feel that the vent are lukewarm but theres no airflow on hot air, if i change it too cold the airflow increases a lot and as soon as i turn it back to hot i feel the airflow dissapear, all this time the fan have the same rpm but i think i can hear it "bein shut in" if you understand what i mean?

    And i can also change the speed of the fan without problem, but i can hardly make out any difference between the modes if i have the dial in warm, if i have them on cold i can tell every mode apart by the airflow so thats why i think it's the mixer actuator that doesn't work, that it keep all that nice hot air for itself :)

    so it might be possible to reset it? gotta give that a try :)

    - - - Updated - - -

    i did check the actuator today and guess what, it works! So now im back to scratch again, what can it be? can i be a clogged heater core? is anyone else of the actuators doing anything with flow or heating?

    If someone know anything about this topic please please help me, we need the heat working, it's not full winter yet and already -10-20 celcius :(

    - - - Updated - - -

    Have anyone in here flushed their heatercore? Feels like that's the thing I hven't tried yet :( that seems however like a major thing to do, that's why I'm asking for advice... Would really appreciate all the help i can get!
  4. RayVoy

    RayVoy Well-Known Member 2 Years 1000 Posts

    If both hoses are hot, the coolant flow is probably good.

    If the air flow is being shut down when you switch from cool to hot, there must be an air flow restriction. You suspected the door and now you think it is working, then there must be something in the air flow in deeper than the door, maybe a rodent nest around the heater core. Can you borrow, rent a hand-held scope, a camera with a 2 to 3 ft flexable lens: (I only picked this one because of the picture).
  5. Kelmannen

    Kelmannen Member

    hmm... didnt even think of that =P can't check for sure now about the hoses (sick in bed atm) but will try that idea for sure!
    is there some kind of filter in these cars? havent found anyone so i guess not :/

    the reason why i think it's cloggd is becuse this car, until i drive it as been used in summer only and the heating package little/never used :/
    Last edited: Nov 18, 2013
  6. Kelmannen

    Kelmannen Member

    Hmm, haven't had the opportunity to check the hoses yet but have noticed that it's coming a lot more hot air if I drive around town compared to driving highway, Guess it's because the engine work/revs alot more? Is there anyone with experience in the area?
  7. RayVoy

    RayVoy Well-Known Member 2 Years 1000 Posts

    Usually if the engine cools off when highway driving, the t-stat is to blame. The thermostat has only one job, which is to stop coolant flow when the temp of the coolant is below "normal operating temperature". When the coolant reaches NOT, the t-stat opens.

    However, you say the rear does not cool off (I assume this is also true on the highway); therefore, the t-stat must be keeping the engine at NOT. Then, the front must have more outside air flowing through the core than the rear (which it does, the outside air flows into the vehicle from the cowl area through the front HVAC. And, when driving on the highway the forward movement is forcing greater amounts of air into the truck, the faster you go.

    So, the reason the air feels cooler on the highway is because the heater core is not heating the additional air.

    We are back to a temp door problem, air flow blockage, or water flow blockage in the core.
  8. Kelmannen

    Kelmannen Member

    did take a video when i tried it out, seems working to me.
    I havent had any more time with the car, i hope i get next weekend to try fiddling with the hoses =/ Im living in a apartment and the garage that i use is ~30-40 miles away from home, can't get much done without it -20 celsius outside now, dont want to be outside if i dont really have to =P
  9. RayVoy

    RayVoy Well-Known Member 2 Years 1000 Posts

    Yep, the actuator appears to be moving correctly; but can you tell if the temp door is being fully moved by the actuator?
  10. Kelmannen

    Kelmannen Member

    well, i dont know what i should be looking after, so no, i can't tell.

    i dont know if it's possible to get a ispection camera inside without aking it apart and if im taking it apart i dont need a inspection camera... :p
    But i just realised something, maybe i can go trought one of the vent ducts? can't go from the fan end without removing the fan but i didnt think about the other end... need to borrow it again next weekend if i can get hold of it again (i can borrow it from a customer of mine if they're not using it themselfs atm.)

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