Two silly oil change questions...

[98G]

I change my oil about every year to year a a half. I don't put on enough miles for that to factor in at all. Rotella 15w40 is my go to with a Wix filter. Fram is well proven to be trash.

Your fresh oil change will be black within two minutes of idling so don't worry about it.

I don't run my M998 in the winter here in Massachusetts because of the huge amount of rock salt we use. I do start her up and warm it to temp every three weeks or so. Just my 0.2 cents.

Mark

I'm not so sure starting it and warming it is a good idea.

Despite the fact that coolant reaches operating temps, without a load on it the internal components don't really get hot. In generators, this practice causes wet stacking.

My MV's also hide from salt over the winter. I put them away with a trickle charger on them and don't touch them again until after the first good spring rain.

 

[87cr250r]

Wet stacking isn't the problem here. That's mostly a generator issue where they run full speed no load.

Condensation is the problem. Every pound of diesel burned produces a pound of water. Exhaust has tons of water in it and any blow-by into the crankcase results in condensation. If the oil isn't hot enough to cook out the condensation the you may accumulate water. Engines without oil coolers or engines with air cooled oil coolers are more prone to accumulating water.

If you want to do the best layup for your engine there are VCI or vapor phase corrosion inhibitors that you can add to your oil for storage.

Vpci-326™ Corrosion Inhibitor Oil Additive 32 Oz | Aircraft Spruce

Vpci-326™ Corrosion Inhibitor Oil Additive 32 Oz An approved Lycoming engine oil additive for prevention of oxidation of all metals. Designed for use in engine oil at 1:10 concentration, VpCI (Vapor Phase Corrosion Inhibitors) wil

www.aircraftspruce.com

 

[98G]

Wet stacking isn't the problem here. That's mostly a generator issue where they run full speed no load.

Condensation is the problem. Every pound of diesel burned produces a pound of water. Exhaust has tons of water in it and any blow-by into the crankcase results in condensation. If the oil isn't hot enough to cook out the condensation the you may accumulate water. Engines without oil coolers or engines with air cooled oil coolers are more prone to accumulating water.

If you want to do the best layup for your engine there are VCI or vapor phase corrosion inhibitors that you can add to your oil for storage.

Vpci-326™ Corrosion Inhibitor Oil Additive 32 Oz | Aircraft Spruce

Vpci-326™ Corrosion Inhibitor Oil Additive 32 Oz An approved Lycoming engine oil additive for prevention of oxidation of all metals. Designed for use in engine oil at 1:10 concentration, VpCI (Vapor Phase Corrosion Inhibitors) wil

www.aircraftspruce.com

What's your opinion on warming it at idle to operating temp every 3 weeks vs letting it sit untouched all winter?

 

[Mogman]

IMHO everyone is over thinking this, many of these sat for 10 years or more with no preparation and some even had well used oil in them.
just keep the batteries charged.
I do not think idling them is a good idea, as others said everything does not get hot enough to burn off the moisture created by this.
If you do want to run it bundle up and take it for a 20 mile or so jog.
BTW I will be taking the DuraVee out with no doors or rear curtain out tomorrow in short sleeves

 

[87cr250r]

What's your opinion on warming it at idle to operating temp every 3 weeks vs letting it sit untouched all winter?

Don't do it. The oil is in the pan, away from the heat generating parts of the engine. If you're just idling it, the oil doesn't get hot and accumulates moisture.

The only reason to start a vehicle regularly is to keep the battery charged. Better to do this with a battery charger.

Engines with carburetors are another story.

 

[MarkM]

I do it to bring the batteries up as I don't have power where my truck is at. If you let the truck Idle for 20min it gets hot enough to get rid of any moisture in the oil. A five or ten min run won't be enough. I have worked on equipment that would run for maybe 5 min to get a job done and after a couple months of that nonsense the oil would look like coffee.

Mark

 

[87cr250r]

That really depends on your oil cooler type. With an air to oil cooler, the oil will not get to an adequate temperature while idling to remove condensation from the crankcase. Without an oil cooler the same is likely true. With an oil to water cooler you can get your oil hot enough while idling to remove condensation but this case is only true if the cooler is on the hot side of the radiator or in the closed loop when the thermostat is shut.

 

[Coug]

For comparison's sake, I work on home standby generators.
This area is kind of damp a lot of the year, and even worse if you live near a body of water.
A typical standby generator run for about 12 minutes once per week (some are set to every other week, and some once a month)

It's very common for me to do maintenance on a generator and find the valve cover, upper dipstick, and a few other places covered in oil/water mix that looks like margarine (literally hydrogenated oil, exactly the same as margarine)

Because these runs are under no load the engine just doesn't heat up enough for long enough to get rid of the moisture. It will typically take a minimum of 30 minutes and sometimes 60 minutes under zero load conditions.

That's with aluminum block air cooled engines, that heat up a lot faster than most cast iron block liquid cooled engines do (they also cool down faster)

The problem isn't just getting the engine oil up to a temp where the moisture can evaporate out of it; you have to maintain that temp while at the same time pulling the moist air out of the engine block. Even if the oil and block are up to temp, if there if a lot of moisture in the air inside the block, it has nowhere to go and will start condensing on the first piece of metal/plastic that drops down in temp. In my example above, it's the dead end passage of the dipstick tube/dipstick and the valve covers.

So to reiterate, it isn't just a matter of getting everything hot enough to evaporate the moisture, you still have to get it all out of the block which takes time.

 

[87cr250r]

This has been a problem for a very long time.

NOTES ON CRANKCASE CORROSION

There is almost unanimous agreement that water in the crankcase is responsible for corrosion in internal-combustion engines. The quantity of water present in the products of combustion of the fuel is dependent upon the hydrogen content of the fuel, the mixture-ratio and the humidity of the air that

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