Northern Lights coolant pressure

[Dave_E]

Hi All,


I have a Northern Lights M643. Recently did a complete service on it (hadn't been used in many years). The unit did not come with a coolant recovery system, just an overflow tube from the radiator cap. Anyway, starts right up, runs like a kitten, but after not even 5 minutes of running, there is coolant coming out of the overflow tube. The unit is no where near it's 180 deg thermostat range yet. If I let it run, the coolant really starts to come out. What is causing this? I replaced the cap because the old one was rusty and the rubber was looking old and weak.


Dave

 

[rslifkin]

With no overflow tank, it'll spit some coolant if it's filled to the top. I'd say let it warm up until it stops spitting, then shut it down and let it cool. See where the coolant level ends up. If it's down about an inch from the top of the heat exchanger, that'll be about the full point.

If you're concerned, you can always add an overflow tank so that the heat exchanger can stay 100% full.

 

[DavidM]

Sounds to me that your old and new cap are both leaking coolant at less than high temp/overpressure conditions. Look at the seat where the cap fits. It may be damaged or rusty, letting coolant out before it should.


David

 

[syjos]

Add a coolant recovery reservoir. They are available online and from auto parts stores.

Northern Lights and most other generators usually come with the reservoirs to be mounted outside the sound shield.

 

[wwestman]

I would add an overflow bottle. Mine has one. This allows for the expansion of the coolant when the motor heats up, then when it cools the coolant returns to the motor. The added benefit is that no coolant goes into the bilge. It is normal for coolant to expand and come out of the tube under the cap, that is why most systems have overflow bottles.

 

[Pete Meisinger]

Water, and antifreeze expand when they are heated, of course you will have overflow. Add a bottle because when the coolant cools and contracts it will create a vacuum and suck the overflow back into the engine.

Pete

 

[Began]

Is the coolant getting lighter and lighter in color as if being diluted by seawater? The heat exchange has 2 rubber "boots" one on each end- tighten up the clamps and see if the flow stops or becomes less. The boots separate the coolant from the seawater and if they are loose your WP pressure could be pushing seawater into the cooling system. You say it sat so hopefully it is just time for new boots. If that doesn't help- stick the end of the overflow hose in a jar filled with water and look for bubbles coming out of the overflow hose- head gasket issues may push compression air in to the coolant and out the overflow.

 

[Ski in NC]

Second the above. Could be leaky boots allowing sea water into coolant. Would also explain the rusty cap. Boots are not that expensive and should be replaced when ever the cooler core is removed.