Removing oil cap after flight.

[Rookie50]

.....read this (couple places) if done immediately for 15-30 minutes may allow boiled off water to escape as steam. Reduction in sitting corrosion.

True or false?

[Prodriver]

That is why there is a breather and you get belly oil on your plane. The engine vents over board.

[Chris M]

Per Mike Busch (I'm paraphrasing): Not a bad idea. Anything that helps that moisture escape is good for the engine.

I usually pop it open after a flight while I refuel and tie down. Just make sure you don't leave the plane like that.

[photofly]

Some enterprising person could invent a thing that twists onto the oil filler and gently blows in dessicated air, exhausting via the breather.

EDIT: like this: http://www.aircraftspruce.com/catalog/e ... gsaver.php

I suspect this and opening the oil filler will remove some of the water vapour from the engine voids and prevent condensation but without data I'd guess the water dissolved in the oil would have too long an equilibrium time with the air surrounding it for 20 mins with the cap off to do much good there.

[Broken Slinky]

Just make sure you don't leave the plane like that.

I leave a piece of paper towel or something hanging out of the oil fill door as a reminder the cap is off. Seen guys put something on the yoke to remind them too.

[digits_]

Just make sure you don't leave the plane like that.

I leave a piece of paper towel or something hanging out of the oil fill door as a reminder the cap is off. Seen guys put something on the yoke to remind them too.

Isn't the chance of damage to the engine due to dust/dirt particles entering the oil/engine while doing this bigger than the possible gains you could get from having some moisture exit the system ?

[photofly]

Seeing as some engines run for decades with chunks of metal turning up in the oil filter I don't think a tiny bit of lint will do much. Just don't push a whole rag inside and leave it there

[Rookie50]

Just make sure you don't leave the plane like that.

I leave a piece of paper towel or something hanging out of the oil fill door as a reminder the cap is off. Seen guys put something on the yoke to remind them too.

Isn't the chance of damage to the engine due to dust/dirt particles entering the oil/engine while doing this bigger than the possible gains you could get from having some moisture exit the system ?

I'm not sure I'd do it outside. Only in my hangar.

[crazyaviator]

ASAS item is a good idea but in Canada we need to remember to block off the hole in the breather above the exit

[digits_]

Seeing as some engines run for decades with chunks of metal turning up in the oil filter I don't think a tiny bit of lint will do much. Just don't push a whole rag inside and leave it there

Probably, but will the small amount of moisture in the oil do more or less bad stuff to the engine ?

[Broken Slinky]

Just make sure you don't leave the plane like that.

I leave a piece of paper towel or something hanging out of the oil fill door as a reminder the cap is off. Seen guys put something on the yoke to remind them too.

Isn't the chance of damage to the engine due to dust/dirt particles entering the oil/engine while doing this bigger than the possible gains you could get from having some moisture exit the system ?

I wrap the paper towel around the stick to allow it to vent and block some of the possibility of dirt. I also put the cowl plugs in. Haven't seen any weird spikes on the oil analysis to say excessive dirt is getting in.

[Therewewere]

The possibility of inadvertently leaving the cap off negates any positive results from the minuscule amount of moisture. Besides don't you think that the engine manufacture has taken this into account?

A very experienced AME once told me never leave anything undone that can be done up. Its just a recipe for disaster.

In over 23,000 hrs of flying, this is one of the dumbest "Myths" that I have ever heard of.

[5x5]

+1 for Therewewere. Risk vs reward simply doesn't compute favourably. Sometimes what seems to make "common sense", just doesn't.

[cgzro]

[quote]That is why there is a breather and you get belly oil on your plane. The engine vents over board. [/quote]

The breather is not there to vent water vapour, its there to vent combustion blow by gasses otherwise you'd blow out the oil seals as the crankcase pressure built up. Of course some water vapour does get vented but not much once the engine stops.

Its very common to leave the dipstick out in the homebuilt/acro crowds but I've never been very convinced as to how useful it is. I think it would be more useful to remove the dipstick and then put air through the breather to force an exchange of air in the crankcase but if the air you put in is humid you may not be doing much good. An exchange of dry air through the engine is probably not a bad idea though.

However by far the BEST thing is to fly a lot ;) ... and drain and replace the oil regularly.

[Zaibatsu]

+1 for Therewewere. Risk vs reward simply doesn't compute favourably. Sometimes what seems to make "common sense", just doesn't.

+2. Fly your plane often, and you don't have to worry about moisture. You've already got a breather tube.

[Heliian]

This oil cap gets opened to check and add oil. That's it.

I would even suggest that you will draw more moisture in as it cools.

[cgzro]

Or blow helium into the case, displace oxygen around the lifters etc. Wonder how quickly it would leak out..

[photofly]

Nitrogen is about 100th the price and just as good.

[PilotDAR]

Nitrogen is about 100th the price and just as good.[as helium]]

... and won't cause a weight and balance change either!

I agree with just fly the plane often, or, preserving oil and desiccant plugs.

[jetmechgm]

I find it difficult to imagine that in the age of human factors and all we have seen on this matter. Poor habits and practices as this exist.
Shame on the the AME that knowingly creates a chance for a inflight engine failure, I can not imagine that would be defined in an MPM or MCM and would create personal liability if an event occurred.