Thread: Cooling systems

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  1. #1
    Member bloodman's Avatar
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    Cooling systems

    I would like to understand a 300 Verado cooling system just a bit. Another thread on a pro xs got me thinking about this. As victim to cold seize on my 250 xs some years ago, I tried to educate myself on the cooling system as best as possible. I know the 250xs temperature was somewhat dependant on water temperature at higher speeds since the poppit opens. I noticed my verado also has a thermostat and poppit. The engine does not care what temps the cooling water is. It runs around 143 no matter what the water or outside air temps are. Why?
    Thanks for any info

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  3. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #2
    A larger portion of the engine's coolant circuit remains on the Thermostatic side of the circuit, AND the oil temp is ALSO thermostatically controlled. Very different from the 2-stroke engine models.

    Also substantially less prone to cold-seizure (Note: "Less-prone"... this does NOT mean it's impossible). The thermostatic control systems (oil and coolant), combined with a cylinder sleeve that does not have open ports in it take credit for this.


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  4. Member bloodman's Avatar
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    #3
    Thank you.
    I know the verados have warning alarms for about everything including cold oil as I did get an alarm one time when I went to take off because the oil wasnt up to temp. I do not accelerate fast in cold water and had warmed the engine, so I thought. I was happy to see this alarm but surprised. Interesting stuff.