Author Running engine temperature in cold weather  (Read 1069 times)

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  • Offline aeroden   au

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    Offline aeroden

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    Running engine temperature in cold weather
    on: September 14, 2022, 07:24:15 am
    September 14, 2022, 07:24:15 am
    Good day guys,

    I noticed when it's 7-12C outside the engine temperature gets down to 65C when I'm cruising on a freeway at 100km/h. Is that normal?

    It didn't go below 65 when it was both 12C and 7C so I would assume thermostat is shutting off radiator flow to the engine warm?

    When it's idling, the fan keeps at around 100C. But on the other hand I would've expected thermostat to shut off the radiator when cruising in cold weather to keep the working temperatures close to 80-85 - to narrow engine operating temperature range (wrt metal parts expansion/contraction, etc.)

    What's your experience?

  • Offline Antares   gb

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    Re: Running engine temperature in cold weather
    Reply #1 on: September 14, 2022, 01:01:25 pm
    September 14, 2022, 01:01:25 pm
    *Originally Posted by aeroden [+]
    Good day guys,

    I noticed when it's 7-12C outside the engine temperature gets down to 65C when I'm cruising on a freeway at 100km/h. Is that normal?

    It didn't go below 65 when it was both 12C and 7C so I would assume thermostat is shutting off radiator flow to the engine warm?

    When it's idling, the fan keeps at around 100C. But on the other hand I would've expected thermostat to shut off the radiator when cruising in cold weather to keep the working temperatures close to 80-85 - to narrow engine operating temperature range (wrt metal parts expansion/contraction, etc.)

    What's your experience?

    65 sounds a little low, mine only gets down to like 75c even on cold winter days

  • Offline Salem   nl

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    Re: Running engine temperature in cold weather
    Reply #2 on: September 14, 2022, 04:38:23 pm
    September 14, 2022, 04:38:23 pm
    Seen from another angle, this 165bhp bike can do 250kph. Very simple calc, just air resistance alone with no respect to mechanical & tire losses & electrical load & wet clutch cooling implies if you are cruising at 100kph you are using 100^2 / 250^2 or just 16% of its power. Also the reason why you get that great tank mileage at that cruising speed. A BMW 310 does that speed  easily, 1000cc is an overkill.

    Thermostats have a weep hole to aid in getting air out. That gives a tiny coolant flow thru the radiator. As the flow is tiny, it gets cooled down  to (too cold) ambient. Just this, and the normal cold air flow might explain it. Radiator is not hot, so cold air hits both the exhaust pipes (not very hot either) and engine block. Might thus be simply too cold and too low of a load on the engine. 

    Simple test would be trying to block the radiator off with carton or plastic  If you have a (BMW) radiator protection not too difficult with tie wraps. 65C coolant is too cold for efficient engine operation, you want 85 or so

    You'd want the oils at 100 C+ plus so it can boil off any condensed water and blow the steam out thru the carter vent. Just my old school thinking

  • Offline Mareng1   gb

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    Offline Mareng1

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    Re: Running engine temperature in cold weather
    Reply #3 on: September 14, 2022, 05:42:02 pm
    September 14, 2022, 05:42:02 pm
    *Originally Posted by Salem [+]
    Seen from another angle, this 165bhp bike can do 250kph. Very simple calc, just air resistance alone with no respect to mechanical & tire losses & electrical load & wet clutch cooling implies if you are cruising at 100kph you are using 100^2 / 250^2 or just 16% of its power. Also the reason why you get that great tank mileage at that cruising speed. A BMW 310 does that speed  easily, 1000cc is an overkill.

    Thermostats have a weep hole to aid in getting air out. That gives a tiny coolant flow thru the radiator. As the flow is tiny, it gets cooled down  to (too cold) ambient. Just this, and the normal cold air flow might explain it. Radiator is not hot, so cold air hits both the exhaust pipes (not very hot either) and engine block. Might thus be simply too cold and too low of a load on the engine.

    Simple test would be trying to block the radiator off with carton or plastic  If you have a (BMW) radiator protection not too difficult with tie wraps. 65C coolant is too cold for efficient engine operation, you want 85 or so

    You'd want the oils at 100 C+ plus so it can boil off any condensed water and blow the steam out thru the carter vent. Just my old school thinking

    What?  If there is entrained water in the oil, then it will boil off at 100c (not on the oil pump discharge side - as the pressure will elevate the evaporation temperature.   The last thing you want is that foaming oil in your sump.   

    Oil should not have a bulk temperature of >100c.

    That’s just my old-school thinking.

    Back to the OP - I think that some further investigation, and possibly a new thermostatic valve.   They are cheap units, and DO jam.

  • Offline Salem   nl

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    Re: Running engine temperature in cold weather
    Reply #4 on: September 14, 2022, 06:09:42 pm
    September 14, 2022, 06:09:42 pm
    (funny with a few answers and 100+ no comment views), i think I disagee with you. These people seem to agree with me. As you stated you can not boil of water on the pressure side. It needs to happen non pressurized in the sump. And that requires 100C+

    edit error in link:

    https://www.verus-engineering.com/blog/informative-8/oil-cooling-a-deeper-look-29

    Last Edit: September 14, 2022, 06:14:28 pm by Salem

  • Offline smithy   au

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    Re: Running engine temperature in cold weather
    Reply #5 on: September 14, 2022, 08:24:07 pm
    September 14, 2022, 08:24:07 pm
    *Originally Posted by Mareng1 [+]
    Back to the OP - I think that some further investigation, and possibly a new thermostatic valve.   They are cheap units, and DO jam.

    Difficult to get at though... :164:

    Smithy.
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  • Offline aeroden   au

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    Offline aeroden

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    Re: Running engine temperature in cold weather
    Reply #6 on: September 20, 2022, 01:15:29 pm
    September 20, 2022, 01:15:29 pm
    Did some tests - to my understanding radiator should stay cold till engines goes to 80+C.

    Well, my radiator heats up quicker than the engine  :087: (started the engine was 22C cold): https://imgur.com/a/VxzFMjk

    Is it highly probable that the the thermostat valve is stuck open?

  • Offline Mareng1   gb

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    Re: Running engine temperature in cold weather
    Reply #7 on: September 20, 2022, 04:48:10 pm
    September 20, 2022, 04:48:10 pm
    If the coolant is being directed to the radiator from start up- I think it is safe to say that the TV is jammed open to it.

     



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