End of season gas question

[Bompa]

I'm looking for some advise for putting my coach away at the end of this season. Yeah, I know it is only August 31.

My question is: What should I do? When I put my coach into storage at the end of last season, I filled the gas tank and added stabil. Due to a severe broken leg, we have not been able to do any trips this year with it. I rented a space at a local campground for the season and there it sits. The total driving this season will be 18 miles to the campground and 30 miles on the way home. I will be taking it a dealer on the way home to have its annual DMV inspection so that I can get it registered next year. I also start it a couple of times each weekend to open and close the slideouts. I plan to change the oil, and grease it when I get home. I am not sure what to do about the gas in the tank. Should I go for a long ride and use it up and refill the tank, or just top it off and add more stabil?

Any advise would be appreciated.

Larry

[pkunk]

Personally, I fill'er up and add some more Stabil. Full tank is best for storage and stabil should preserve it. You will probably lose some 'pep' (stale gas) but not worth going out to just burn it off. Next time out, after several hundred miles, fill up again with 'fresh' gas and it will be back to normal.

[kalynzoo]

Hi Bompa. Since you don't have a profile, I'm not sure where your storing the MH. In Southern California, I always have the gas tank full, or almost full, water on board, and 3/4 propane. During the 94 Earthquake, epicenter my house, we lived out of the MH for 6 weeks till other shelter could be arraigned. The generator was the only power on the block, and was shared will all the neighbors. Today the valley is surrounded by wildfire. It is far enough away that it will not affect my family. Although last year the fires got pretty close. If there were to be an evacuation I could either move out and relocate the MH to save ground, or I could use it as sleeping quarters for friends or family that had to evacuate.

We think of the MH when not in use as a large Emergency Box.

Truly hope you never need a full tank of gas, but it is nice to know it's there.

Happy Trails.

[Guest 2driftrs]

We always keep our tank full when the rig's not in use. Like kalynzoo said, you never know. In December of 2002 we had an ice storm that took out the power for 10 days. If it weren't for the coach and generator, we'd likely have frozen.

They say you should always keep your tank full when not in use to prevent condensation from forming then settling in the bottom of the tank, making rust. So they say - - I'm not sure how the moisture gets in the tank to begin with, but who knows? Back in the days of leaded gas and vented to the atmosphere fuel systems, this was a problem, but with today's sealed systems, I'm not so sure.

If you have to store your coach, the best advice we can give is run it at least once a month, and more often if possible. And by run it, I mean drive it at least a mile or so. When any vehicle sits idle for just a few days, rust forms on your brake rotors. Oil starts draining from vital engine and transmission parts. Grease is being forced out of the minuscule space between bearings and bearing races. Run the cab and roof air units for a few minutes. Turn on the water heater, the fridge, etc. That way, everything stays "fresh", and your coach will be ready to roll the next season.

Don't be like a poor sole I met back in the days when I did lots of boating - - he put his jet boat in storage for the season and on the first nice spring day the next year, filled the tank and took it to the lake, backed the trailer into the water, let the boat float off the trailer, tied her to the dock and then spent 2 hours (unsuccessfully, I might add) trying to get it started!

Jan and Barry

[wolfe10]

They say you should always keep your tank full when not in use to prevent condensation from forming then settling in the bottom of the tank, making rust. So they say - - I'm not sure how the moisture gets in the tank to begin with, but who knows? Back in the days of leaded gas and vented to the atmosphere fuel systems, this was a problem, but with today's sealed systems, I'm not so sure.

If you have to store your coach, the best advice we can give is run it at least once a month, and more often if possible. And by run it, I mean drive it at least a mile or so. When any vehicle sits idle for just a few days, rust forms on your brake rotors. Oil starts draining from vital engine and transmission parts. Grease is being forced out of the minuscule space between bearings and bearing races. Run the cab and roof air units for a few minutes. Turn on the water heater, the fridge, etc. That way, everything stays "fresh", and your coach will be ready to roll the next season.

Jan and Barry

You make some good points. I will address two of them.

First: how condensation forms in the tanks was discussed here on another thread (concerning diesels). Using that as a basis, I will post it here:

First, let's look at what happens if you park your coach with 1/3 tank of fuel -- assume total capacity 75 gallons.

As you burned the 50 gallons of fuel, that space in the tanks was replaced with AMBIENT AIR, at whatever temperature AND HUMIDITY the outside air is at that time. So you now have 25 gallons of fuel and, particularly, if driving in a hot/humid area, 50 gallons of hot HUMID air.

OK temperature drops to the dew point OF THAT HUMID AIR IN THE TANK. It CONDENSES. And since water is heavier than fuel, it goes to the bottom of the tank and contaminates the fuel and/or rusts the tank.

Each day, as the temperature rises, air and fuel in the tank EXPAND-- actually, air just goes OUT of the tank through the vent line/charcoal canister. This happens even if the 50 gallons of air in the tank was dry and/or cold.

Each night, as the temperature falls, air is sucked into the tank through the breather line. As temperature continues to drop, the water vapor CONDENSES and goes to the bottom of the tank.

Repeat 30-100 times. NOT GOOD!!!!!

And yes, even if you are a desert area, your tank WILL get down to the dew point and there will be condensation.

If you fill the tank before parking, there is a MUCH smaller volume of air to condense. Also, liquid (fuel) expands and contracts much less with temperature change than a gas (air) so there is far less "breathing" of the tank.

Second: If you start the engine while storing the coach, you need to run it long enough that the OIL gets up to operating temperature. This generally means 25 or so highway miles. The object of driving while stores is manyfold as you point out, but one of the primary things you are doing is riding the crankcase of moisture. This only occurs when the OIL (not just coolant) gets hot and stays hot long enough to "vent" the moisture (through PCV valve on gasoline engine and through crankcase breather on a diesel).

Brett Wolfe

[skyking8]

I have a friend who is a certified diesel mechanic working for a major airport where there is a lot of heavy equipment. Much of their equipment may sit idle for extended periods. They always keep the tanks full, but another trick is to use a small portable compressor to bubble some air into the tanks on occassion. This is supposedly a mold prevention issue. Any comments?

[wolfe10]

I have a friend who is a certified diesel mechanic working for a major airport where there is a lot of heavy equipment. Much of their equipment may sit idle for extended periods. They always keep the tanks full, but another trick is to use a small portable compressor to bubble some air into the tanks on occasion. This is supposedly a mold prevention issue. Any comments?

First, with a full tank, the amount of air in the tank will be limited.

Will it help to replace that air in the tank with DRY air-- well it sure won't hurt.

BUT, remember with temperature swings every day, the air "changes itself". Each day as the temperatures rise, the air expands. Since it is "trapped" in the tank, it flows out the tank vent (unlike gasoline tanks, diesel tanks ARE vented). Each night as temperatures fall outside air is drawn back into the tank. So like it or not, the air is constantly "changing". The temperature swing dictates how much moves in and out each "day cycle".

You can do this experiment to see how this works. Take a gallon plastic milk jug. Cap it tightly. Put it in the freezer. After a couple of hours take it out and remove the lid. It will suck IN air-- just like your tank. If made of thin plastic, the sides of the jug may even be sucked in when you remove it from the freezer. You could also place it in the freezer with the lid off. Cap it. Remove it and place in sink of warm water. Remove the lid and feel the OUT-RUSH of air. Kind of takes you back to Mr Wizard doesn't it!

This is the main reason for storing with full fuel tank-- to minimize the air exchange. Why-- because the air that is sucked back into the tank on cold nights is often at the DEW POINT and it introduces moisture to the tank.

Bottom line, "changing the air" in the tank sure doesn't hurt anything, but I suspect it is more of a "feel good" than significant improvement. Now, if the tank were only 1/2 full, introducing "dry air" would be more of an advantage. But, none of us do that DO WE?!!!

Brett Wolfe