Sully2
Cincinnati
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Joined: 01/20/2003
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wolfe10 wrote:SunflyerA wrote:...still I don't understand why an engine that is not started would have condensation.
The engine is NOT a sealed unit. As temperatures rise, air moves out of the engine crankcase(gas or diesel). As temperatures drop, air moves back into the crankcase.
EACH TIME the temperature drops to the dew point of the air in the crankcase, condensation occurs.
Prove it to yourself. Take a cheap disposable water bottle. Fill it on a warm, humid day. Stick it in the freezer. You will notice two things: there will be moisture droplets inside and when you remove the lid, it will suck in more air from the outside.
Your analogy is dead on target but let me ask this..??
When MY coach goes into storage..its WINTER time... So how much "humidity" is in the air at 35 degrees F..?? And then the temp drops to say 20 or 15 above zero F..? I think if you check real close your see the amount of moisture that gets squeezed out of the air at those temps amount to about "1 human tear drop".. (i.e. not a whole heck of a lot!!)
I might not be exactly correct but if ( poor memory) memory serves me 1/2 way...that below a certain temp ( which I think is 26 degrees) the chance of SNOW is about "point squat" because the vast majority of moisture has already been squeezed out of the air!!!
So the concept of an engine "breathing" like one of those fake antihistamine bottles in a TV commercial.."aint quite right"!....
2000 Country Coach Allure; Cummins ISC 330 HP; 71/2 - 8 MPG regardless
2002 Jeep Liberty
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topflite51
In The Desert of Nevada
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Joined: 05/13/2004
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I was taught that one should change the oil in the fall, thus removing any contaminants that may have gotten in during the usage season, especially if they were to sit unused till spring. You never know how much or little unburnt fuel makes it past the rings into the crankcase, or for that matter how much condensation has entered during the usage season.
 David
Just rolling along enjoying life
w/F53 Southwind towing 87 Samurai looking to golf or fish
Simply Despicable
Any errors are a result of CRS.
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7bobw
Granite Bay. CA. USA
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Joined: 01/17/2005
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Use the coach all year and you won't have to decide.
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SKIPPERS_1
INDIANA
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Joined: 07/29/2007
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69RoadRunner wrote:SKIPPERS_1 wrote:69RoadRunner wrote:Well, I try to drive the MH a few times out on the highway during the winter if there's not salt/snow/ice on the roads to circulate oil to parts that need to be lubricated, and reduce flat spots on the tires.
So, I change it in the Spring.
I like your toad.
Thanks!
I'm one of the few who have a toad that gets the same mileage as the motorhome and has much more power than the motorhome. 
I know what you mean I have a 68 vett, the old foot gets heavy from time to time
1999 DUTCHSTAR DP
38`
8.3 ISC CUMMINS
SPARTAN CHASSIS
1994 TRACKER 4X4 TOAD
BLUE OX TOW BAR
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427435
Rochester, Mn
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Joined: 11/12/2005
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As Sully points out, the amount of moisture in cold air is quite small. And the amount of air that moves into today's closed crankcase system is very small on top of that. In any event, the water itself isn't the biggest concern. However, water combined with combustion by-products will form acids------which is what can be bad. An engine stored after a fresh oil change will have little if any combustion by-products in the oil------and there will be plenty of additives available to deal with what little is there.
It's your engine, but mine gets changed before storage.
Mark
2000 Itasca Suncruiser 35U on a Ford chassis, 65,000 miles
2003 Ford Explorer toad with US Gear brakes,
Ready Brute tow bar, and Demco base plate.
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wolfe10
Texas
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Joined: 10/08/2000
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Sully2 wrote:Your analogy is dead on target but let me ask this..??
When MY coach goes into storage..its WINTER time... So how much "humidity" is in the air at 35 degrees F..?? And then the temp drops to say 20 or 15 above zero F..? I think if you check real close your see the amount of moisture that gets squeezed out of the air at those temps amount to about "1 human tear drop".. (i.e. not a whole heck of a lot!!)
Gary,
Enclosed engine volumes certainly vary. There are many gallons of "air" in your engine and mine (crankcase, passages for push rods, etc, space between head and valve cover, etc). Gasoline engines do have lesser volumes.
Clearly, there are many different climates in the U.S where coach's sit all winter.
In many areas, the temps and humidity cycle over a very wide range. Certainly in Texas (even north Texas) as well of many areas south of the Mason Dixon line we get winds from the South and then Southwest BEFORE cold fronts. So Gulf of Mexico moisture streams north and then the temperatures PLUMMET.
As an example, in our area when the cold fronts arrive, there is condensation in the INSIDE of our stick home windows. That is moisture condensing!
You may live in an area where this doesn't occur-- I have no first hand information. Remember, Dianne and I head SOUTH from Texas in the winter!
As an ex-Yankee once told me when speaking of climates he liked, "If an orange tree is happy, I'm happy".
But, we digress. You are going to change your oil once a year. I certainly change mine before storing it.
Brett Wolfe
1993 Foretravel 36' U-240
Cat 3116, Allison 3060
FMCA Forum: www.community.fmca.com/index
Caterpillar RV Engine Owner's Club: www.catrvclub.org
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stevelv
Living on the island
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Joined: 05/24/2006
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Seems real simple to me.
1. Old oil is contaminated - over time those contaminents are going to cause corrosion to metal parts especially in areas where the oil film breaks down as it all drains into the sump.
2. IF the engine breathes in moisture as some have alluded to, as soon as it gets to temperature when it's restarted in the spring, that moisture will evaporate anyway. It's going to be a miniscule amount anyway.
If you can afford to change oil when you park it AND when you bring it out of storage then go for it - it won't hurt anything other than your wallet.
Otherwise change it before your store it away.
RV Park Finder
Ex Fulltimers
Restored a 1984 Monaco Regent - now with new owner
DH,DW,Jake and Indie
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