Sunday, September 20, 2015

Understanding Engine Pre-heat

Thanks to my friend Mike Fultz for providing all of the information (that I've merely explained) and for reviewing it for accuracy.

It's a good idea to be able to pre-heat the engine before you start it up in a cold environment.  To do this (in the Dutch Star and probably in others), there's a standard item listed in the brochures as "Engine block heat", meaning that a heating device actually heats the engine oil pan, thus providing heat to the engine.  For this to work, you have to open up the back of the Dutch Star and plug in the heater (there's a 110V outlet there with the plug nearby), then go to the inside console and turn on the Engine Heater switch.  This also requires the coach to have access to 110V power.  Often, when dry camping or parked in a storage lot, 110V is not easily accessed.

In addition to the Engine Block Heater, there's a switch on the Oasis control panel located in the console above the passenger seat that is marked "Engine Preheat".  Originally, turning this on caused a control valve in the Oasis Distribution box to open and circulate a liquid (diesel or shore/generator powered) through the Cummins engine water jackets to preheat the engine.

However, Newmar has changed the way this works.  The "Engine Preheat" console switch actually doesn't do anything anymore.  That's because they have routed the liquid (ethelyne glycol) through the engine water jackets all the time.  This serves two purposes:  it preheats the engine and it also uses the engine's waste heat to heat up water to use for sinks and the shower or to provide heat to the coach.

Because of this new method of plumbing, often referred to as "motoraid", the engine can now be preheated in subfreezing weather using only the Oasis and without having to use the generator or shore power.  This is possible because the Oasis can run on its own with its diesel fueled burner.

To use it without shore power or the generator, you have to make sure the Oasis is on (the switch is on the Oasis itself, but you probably already have it on if you're camping somewhere because you're using hot water all the time), and you have to turn on the Burner switch in the console. This causes the Oasis to "burn" diesel fuel to heat up the liquid.

All of this is standard.  There's nothing special to order.

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