Volvo VNL 780 keeps overheating

Discussion in 'Volvo Forum' started by Ladytrukr, Aug 12, 2017.

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  1. Aug 13, 2017 #11
    Ladytrukr

    Ladytrukr Bobtail Member

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    I want to add a manual fan switch also, I've heard is much better and keeps everything way cooler
     
    Ladytrukr, Aug 13, 2017
    Ladytrukr, Aug 13, 2017
    #11
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  3. Aug 13, 2017 #12
    uncleal13

    uncleal13 Road Train Member

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    The fan can be turned by hand until the system gets low on air then you won't be able to turn it. Sounds like it is ok.
     
    Last edited: Aug 13, 2017
    uncleal13, Aug 13, 2017
    uncleal13, Aug 13, 2017
    #12
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  4. Aug 13, 2017 #13
    Ladytrukr

    Ladytrukr Bobtail Member

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    Ok so to check, should I pump the brakes until the air is low and then try to spin the fan?
     
    Ladytrukr, Aug 13, 2017
    Ladytrukr, Aug 13, 2017
    #13
  5. Aug 13, 2017 #14
    KB3MMX

    KB3MMX Road Train Member

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    Yes that's a great mod I've done to my trucks, highly recommend it
     
    KB3MMX, Aug 13, 2017
    KB3MMX, Aug 13, 2017
    #14
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  7. Aug 13, 2017 #15
    Ladytrukr

    Ladytrukr Bobtail Member

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    So I pumped the brakes until the low air warning came on... and the fan doesn't turn freely but it still moving. Is it supposed to move at all or no?
     
    Ladytrukr, Aug 13, 2017
    Ladytrukr, Aug 13, 2017
    #15
  8. Aug 13, 2017 #16
    me myself and I

    me myself and I Heavy Load Member

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    No, you most likely need new fan clutch. Should not cost more then 1k
     
    me myself and I, Aug 13, 2017
    me myself and I, Aug 13, 2017
    #16
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  9. Aug 13, 2017 #18
    Rob100100

    Rob100100 Light Load Member

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    That is normal. Fan will come on around 210 and stay on till temp drops to about 180 to 190. Fan should not move after turning off engine. Btw do not cook your engine by running it hot. Bad things happen, bad things.
    If it running hot you need to have it looked at very soon.

    Good luck post what happens please
     
    Rob100100, Aug 13, 2017
    Rob100100, Aug 13, 2017
    #18
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  10. Aug 14, 2017 #18
    nasriza

    nasriza Road Train Member

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    just turn on ac while on idle with hood up and yoiu should see fan cycle on and off if working properly, either your radiator is blocked or you might actually need a thermostat.
     
    nasriza, Aug 14, 2017
    nasriza, Aug 14, 2017
    #18
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  11. Aug 14, 2017 #19
    me myself and I

    me myself and I Heavy Load Member

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    Should she ba able to spin fan when its engaged?
     
    me myself and I, Aug 14, 2017
    me myself and I, Aug 14, 2017
    #19
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  12. Aug 14, 2017 #20
    KB3MMX

    KB3MMX Road Train Member

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    Let me confirm, you are talking about high coolant temperature right....?

    Bleed down all your air pressure with the engine off then try and spin the fan.

    If it spins by hand with no air pressure it's got a dead fan clutch.


    .
     
    KB3MMX, Aug 14, 2017
    KB3MMX, Aug 14, 2017
    #20
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