Where is the “Ice Hole” on the Ovation breather tube??

[William Munney]

Hello all:

Installed an Engine Saver engine dehumidifier on my Ovation.  It works by pumping dry air at low PSI through the breather tube, through the crankcase and cylinders and out the exhaust valve(s) through the exhaust.  The tube from the machine goes into the breather tube and has rubber gaskets attached to it to prevent air from coming back out the breather tube.  This only works if the gaskets are above the ice hole in the breather tube.  Otherwise i am pumping dry air out the Ice Hole.

The tube seems navigable with the hose/ gaskets for about 8” or so and then runs into a bend or obstruction that prevents further insertion.  I am asking so I don’t have to de-cowl the airplane…..which i will do if I have to but I am looking for the short answer if anyone has it.

The Engine saver is supposed to lower internal engine humidity to 5% or lower and it’s super simple to use so i would like to keep it.  But, I can only do that if I am above the ice hole with the dry air tube/ gaskets.

 

[Scott Ashton]

I have the same one - on the IO360 it’s quite a ways up the tube and you have to give the supply tube a good shove to get up past the ice hole.    I have the tube marked so I know how far to put it - I did that when I changed the oil.

Buy a few jugs of dessicant in order to swap it out when it’s turns pink, so you can bake the used stuff at your leisure.

baking the dessicant is a pain.   I probably should have gone for the Drybot instead.    Those guys were in the booth next to me at Oshkosh for the last two or three years and it’s a nice product.   

 

[William Munney]

Thanks for getting back to me.

I have an oil change on Friday so i will locate the hole and mark the supply tube.  I looked at the Drybot and Black Max and both required sending the entire unit back to the manufacturer every few years plus replacement parts.  And, the Drybot was 3-4 times more expensive.  I did buy the extra canister of desiccant.  In the summer (humidity) the canister should last 3-4 months.  In the Winter….you might get 7 months out of it.  Might have to bake the beads once or twice a year.

I just ordered a humidity probe. I’ll place it in the exhaust a ways up there and that should tell me a lot about what’s going on inside the engine.

Overall, seems like a small investment for an expensive engine.  Most of the data says the engines are not wearing out before they are rusting out.

The engine in my airplane at the time of purchase was rusted internally from flying 30 hours in 6 years.  I ordered a factory new IO-550 the same day i bought it.  Trying to keep it in good shape with regular flying and now this de-humidifier.

[Rick Junkin]

20 hours ago, William Munney said:

The Engine saver is supposed to lower internal engine humidity to 5% or lower and it’s super simple to use so i would like to keep it.  But, I can only do that if I am above the ice hole with the dry air tube/ gaskets.

I insert the tube in the oil filler neck instead of the oil breather tube.

I had the same issue with my Bravo and decided to get a silicone stopper that fit the oil filler neck opening and drill a hole in the center of it to fit the Engine Dehydrator tube. I remove the dip stick after every flight to let the moisture escape while the engine's hot, and then insert the stopper with the dehydrator tube. That gets the dehydrated air to the top of my Lycoming where it's needed most, and logically makes its way through the rest of the case. If I'm going to be down for an extended period I have dehydrator plugs to replace the top plug in each cylinder.

6 hours ago, Scott Ashton said:

baking the dessicant is a pain.

I use a toaster oven at the hangar with two stainless steel baking pans. It takes about an hour at 250º to dry a batch of desiccant. I store both the used and dried desiccant in separate large flat tupperware-type containers. It's easier to empty the dehydrator jug and the baking pans into the larger plastic containers. And then when the time comes to dry or change desiccant I use a Solo cup to transfer the desiccant from the plastic container into the oven pans or the Engine Dehydrator jug. Sure it takes a little effort but it's easy and the drying doesn't have to be done all in one visit to the hangar. Having an air-tight container to store the dried desiccant is the key.

Cheers,

Rick

[Slick Nick]

I think Rick has the right idea about going in through the top. If internal moisture is an issue, an exhaust ball might help. 

[Schllc]

Seems like a lot less hassle to just fly regularly…

[Rick Junkin]

2 hours ago, Schllc said:

Seems like a lot less hassle to just fly regularly…

No doubt, and my preferred approach!  

But sometimes mx and health issues got in the way of that. And now I’m stuck because our runway is closed until December while they rebuild it and I wasn’t able to get The Beast moved before construction started. For those times I can’t get the airplane airborne these measures are prudent and work well.

[Gee Bee Aeroproducts]

On 9/10/2025 at 6:27 AM, William Munney said:

Thanks for getting back to me.

I have an oil change on Friday so i will locate the hole and mark the supply tube.  I looked at the Drybot and Black Max and both required sending the entire unit back to the manufacturer every few years plus replacement parts.  And, the Drybot was 3-4 times more expensive.  I did buy the extra canister of desiccant.  In the summer (humidity) the canister should last 3-4 months.  In the Winter….you might get 7 months out of it.  Might have to bake the beads once or twice a year.

I just ordered a humidity probe. I’ll place it in the exhaust a ways up there and that should tell me a lot about what’s going on inside the engine.

Overall, seems like a small investment for an expensive engine.  Most of the data says the engines are not wearing out before they are rusting out.

The engine in my airplane at the time of purchase was rusted internally from flying 30 hours in 6 years.  I ordered a factory new IO-550 the same day i bought it.  Trying to keep it in good shape with regular flying and now this de-humidifier.

Nice install of my seals !

[Scott Ashton]

re: going up the breather tube, when I went to depart on Friday for MooneySummit, with I pulled on the tube to remove it, it separated inside the tube at one of the joints.   Not far enough where I couldn’t get it with a pair of needle nose, but enough to end that practice and putting it into the oil fill tube from now on!

[GeeBee]

The problem with the breather tube is as said, it can separate. The problem with going in from the top is you need to bypass the breather tube which connects at the top of the oil filler neck. I took a small skinny funnel, I put the tube. down the funnel until it was flush with the exit of the funnel. I then filled the funnel with "Flex Seal" liquid rubber and let it sit overnight. Now the tube is fixed in the funnel. I remove the dipstick, stick the funnel in which bypasses the breather outlet and nearly connects to the oil tube below with a seal. The funnel nicely seals around the oil filler neck and the dry air gets down into the crank case. I will post a picture of my unit.

[Rick Junkin]

18 hours ago, GeeBee said:

The problem with going in from the top is you need to bypass the breather tube which connects at the top of the oil filler neck.

Hijacking the thread a bit - is this only true for Continental engines? Best I can tell on my Lycoming TIO-540 the breather is on the accessory case. Granted, in any case I loose any possible pressurization of the case by attaching the dehydrator at the oil fill tube because the breather is not sealed. My fluid dynamics knowledge is really rusty but I think the dryer air will still permeate the whole case, just less efficiently/effectively.

[Rick Junkin]

Found this on the ACI website. They must have received complaints/questions about how to get the tube inserted in breather tubes with big bends and ice holes further up the tube. Looks like a reasonable solution for the issue:

https://flyingsafer.com/shop/ols/products/2065-2-folley-cath-adapter-kit

I may give this a try. A Foley is pretty durable, but I wonder how long they expect it to last before needing replacement.

[GeeBee]

8 hours ago, Rick Junkin said:

Hijacking the thread a bit - is this only true for Continental engines? Best I can tell on my Lycoming TIO-540 the breather is on the accessory case. Granted, in any case I loose any possible pressurization of the case by attaching the dehydrator at the oil fill tube because the breather is not sealed. My fluid dynamics knowledge is really rusty but I think the dryer air will still permeate the whole case, just less efficiently/effectively.

Yes. I was referring to Continentals. Lycomings are easy, get a holed rubber scientific flask stopper of the appropriate size, stick a piece of tubing through, put the stopper in the oil filler in place of the dip stick

Here is my Continental solution:

Use pourable flex seal to seize the tube in the funnel

Funnel sits nicely and seals the filler bypassing the breather tube. Much easier than snaking up the breather line.

 

 

[William Munney]

After the oil change I can confirm that for the IO550 installation in the Ovation the “ice hole” is way too far up the breather tube to make it possible or safe to use the breather tube method with this unit.  You are all correct going down through the oil filler tube.  How far down that tube is the breather tube entrance??  Or, how far down the oil filler tube do I have to insert the plastic tube from the dehumidifier unit??.

[Marc_B]

On 9/15/2025 at 11:58 AM, Rick Junkin said:

A Foley is pretty durable, but I wonder how long they expect it to last before needing replacement.

usually replace them once a month to prevent colonization 

[Rick Junkin]

1 hour ago, William Munney said:

After the oil change I can confirm that for the IO550 installation in the Ovation the “ice hole” is way too far up the breather tube to make it possible or safe to use the breather tube method with this unit.  You are all correct going down through the oil filler tube.  How far down that tube is the breather tube entrance??  Or, how far down the oil filler tube do I have to insert the plastic tube from the dehumidifier unit??.

Did you see @GeeBee's posts above? Looks like a pretty elegant and effective solution and answer to your question.

[William Munney]

I did see and ordered a thin funnel from amazon today.  How far down the oil filler tube is the entrance to the breather tube??

[GeeBee]

The breather tube is close to the top of the filler neck. The funnel will get you past that and seal with the filler hole to the case. When you are making your funnel, wrap electrical tape around the flex tube before inserting it funnel to create a seal so the Flex Seal does not leak out the bottom as it cures.