coolant - reservoir full but radiator half-empty

Discussion in '1st & 2nd Generation 1983-1989' started by chuntera, Aug 4, 2013.

  1. chuntera

    chuntera New Member

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    My limited understanding of automotive cooling systems says the radiator should be able to pull coolant from the reservoir when the radiator level drops.

    What conditions would this not happen ?
    - pressure leak in a line (ie. is the reservoir pressurized ?)
    - thermostat blocked ?
    - radiator leak ?
    - radiator cap blocked ?
     
  2. friedleyjr

    friedleyjr New Member

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    Is the hose clogged by chance?
     
  3. friedleyjr

    friedleyjr New Member

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    The fluid goes in and out by air pressure so also a crack could cause the issue.
     
  4. squirrelman

    squirrelman Member

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    Loose or cracked line from rad to bottle will do that as well as a bad cap. Just why i'm always advising that the best check of coolant level is under the rad cap, NOT the bottle. Loosing too much fluid from rad brakes the liquid connection between it and overflow. So, yes, if certain things are not working right, your radiator could be empty while the bottle is full.

    First thing to try is a new rad cap :cool: and close inspection of the rubber line.
     
  5. friedleyjr

    friedleyjr New Member

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    Calcium build up could be causing the issue too. You can fix this by removing the hose and soaking it in hot soapy water. Then blow the hose out with air, also try filling the fluid all the way up and draining the overflow container to about a quarter of the way. Make a mark with sharpie to get a starting level. Ride it for a weekend, let it cool down then check you level in the reservoir. if there is a increase in fluid get a tech to look at it as this could be an internal engine problem. With cars generally means blow head gasket. Like squirrel said the cap could be bad also, pay close attention to the gaskets in the cap look for tears or cracks. GL fixing problem and I hope it is simple like replacing a hose or cap.
     
  6. Scubalong

    Scubalong Official Greeter?

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    All good advise here :thumbsup:
     
  7. chuntera

    chuntera New Member

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    I replaced the thermostat and rad cap. I refilled coolant at the radiator. I confirmed the thermostat is opening.

    Now the overflow reservoir puking after every ride. The radiator coolant level gradually runs down and needs to be refilled periodically . The reservoir basically stays full.

    I am guessing the system has to be pressurized for the reservoir to overflow, so I am not sure there is a leak in a coolant line. Maybe the new rad cap is faulty ?
     
  8. Lobotomy

    Lobotomy New Member

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    on my 85 there is a bleeder screw on the thermostat housing. I had a problem after changing
    fluid because of air in the system. I bled out some air and coolant and it was much better. it still
    was not perfect but after a bit of riding and topping up at the rad cap everything is working fine.


    Garry
     
  9. jugornot

    jugornot New Member

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    Pressure is contained in the radiator by the cap. Once pressure exceeds the pressure rating of the cap it is forced out through the hose to the hose to the overflow. All under normal air pressure. WHen the bike cools a vacuum forms in the radiator. This pulls the fluid back into the radiator. The spitting out fluid could be overfill and the engine getting warm. If it has a line for cold fill to that line. This leaves room for expansion when hot. This sounds maybe OK. The fact that you have to add to the radiator makes me believe you have a pinhole leak that allow air in the radiator as the bike slowly cools. Or you have a blown head gasket that is pressurizing the radiator. And allowing air back in not letting the vacuum pull the fluid back in. I suggest pressure testing the cooling system. That will let you know if you have a leak.. You may be able to check compression to find a blown gasket or cracked head or such. If you have a leak you could pull the radiator and pressurize it under water. May also be hoses or the water pump. Good luck.
     
  10. jaripetteri

    jaripetteri New Member

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    Old thread but I have exact same symptoms on my -04 Vtec. Did you find out the reason? I have changed the cap and reserver tank hose. Now waiting pressure tester to pressurize the coolant system and find out the leak. Just hoping it is not head gasket...
     
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