Winterization Plate

[GeeBee]

I have a mission that requires start up at 22 degrees F and landing at 46 degrees F. I will keep the airplane in a pre-heated hangar before start up. I have a factory installed winterization kit so I can install an oil cooler block off plate before departure. The AFM says I need to remove above 30 degrees. Can I safely fly the entire flight with the plate installed. I will be cruising around 10K and I am running 15W-50 oil.

[Fly Boomer]

16 minutes ago, GeeBee said:

Can I safely fly the entire flight with the plate installed.

If you will depart from a heated hangar, and arrive in milder temperatures, why not take it off before departure?

[Slick Nick]

You’ll be fine. I keep the oil cooler in my J half taped off in winter and it’s had no problem up to +10*C

[AspiringOwner]

My IO550 runs very cold. Even with the plate installed I see oil temps only reach around 150-160 in the winter (OAT -10 C).  For your flight I would definitely keep it in. I would consider switching to a different oil though. The semi synthetic 15W50 is actively discouraged by some, e.g. Savvy. 

[anthonydesmet]

17 hours ago, GeeBee said:

I have a mission that requires start up at 22 degrees F and landing at 46 degrees F. I will keep the airplane in a pre-heated hangar before start up. I have a factory installed winterization kit so I can install an oil cooler block off plate before departure. The AFM says I need to remove above 30 degrees. Can I safely fly the entire flight with the plate installed. I will be cruising around 10K and I am running 15W-50 oil.

GeeBee, you will be fine. I’ve had to do same for years when we go to Illinois or Iowa and Boston. I preflight, load bags, pax and dog in hanger then have line crew open doors and tow us out. The plane wont be cold soaked by the time you turn motor over. Worse thing about cold operations is engine start….(well besides, icing, temp inversions, etc)…..Oil will still be in the 50’s or above by the time you start.

[GeeBee]

Yes, I usually hangar, preflight and tow out my real concern was what happens when I arrive in the warm weather with the plate still in. 

As to the oil, I have heard those concerns but I ran a fleet of C-402's with never a problem with starter adapters or anything else on Aeroshell 15W-50. I know the "small sump" syndrome on the IO-550 but I rarely take the oil beyond 40 hours. What many including Savvy do not understand is all multi-viscosity oils are semi-synthetic including Phillips 20W-50, they just don't state it. They have to be by definition of the manufacturing process.

[McMooney]

at what temps do we need this winterization kit,  at some point i'm gonna fly where it's cold.  

 

[GeeBee]

For my R model is says remove it above 30 degrees. It does not say when it needs to be installed as it is optional except the AFM says:

For engine operation at outside air temperatures below - 25oC (- 13oF), the engine and

engine oil should be preheated to at least - 25oC (- 13oF) before the engine is started.

Continental says you need to pre-heat when below 20 degrees F for more than two hours. 

Lycoming says:

Engine operating temperature is another item that is not usually given enough consideration in cold weather. We usually are very cautious about high oil temperature which we know is detrimental to good engine health, while a low oil temperature is easier to accept. The desired oil temperature range for Lycoming engines is from 165˚ to 220˚ F. If the aircraft has a winterization kit, it should be installed when operating in outside air temperatures (OAT) that are below the 40˚ to 45˚ F range. If no winterization kit is supplied and the engine is not equipped with a thermostatic bypass valve, it may be necessary to improvise a means of blocking off a portion of the airflow to the oil cooler. Keeping the oil temperature above the minimum recommended temperature is a factor in engine longevity. Low operating temperatures do not vaporize the moisture that collects in the oil as the engine breathes damp air for normal combustion. When minimum recommended oil temperatures are not maintained, oil should be changed more frequently than the normally recommended 50-hour change cycle. This is necessary in order to eliminate the moisture that collects and contaminates the oil. 

[MarkD34M]

GeeBee:

 

I think you will be perfectly fine without the plate. I live in the cold northeast and do not run one. Temps get up to operating in the normal range without an issue.  Have a good trip!

 

Mark

[dkkim73]

For the Acclaim at least (with the cowl and baffling design), I've been surprised how robust it is either with or without the plate. I didn't have one for a while and, after reading a bit here, used metal duct tape on part of the oil cooler. Had a couple of wicked cold but needful flights where I had to run ROP, later on with this tape, to keep CHT's in the green (at least during descents or lower power settings). 

I was looking for a "winterization kit". Which sounded like a flat metal plate. At one point, my mechanic took pity on me and fabricated a little triangular plate when I was in for some other work. Does the job nicely. 

On the flip side, I left that plate on until the end of July; it just crept up on me, I think. All the #s were pretty good during this time, so it just occurred to me one day. Looking at a few Savvy and FlySto monitor logs just now, I see anywhere from a 10-30F difference before and after looking at a couple flights, but it's hard to compare apples-to-apples without doing some actual numerical analysis to account for ambient temp, transient changes during different flight regimes, etc.

My gut conclusion was that this installation is pretty robust either way. 

[Slick Nick]

I use tin tape on the oil cooler in my J. I put on a couple pieces, each subsequent one covering one more row of cooling fins than the last. Makes it easy to reach in and pull one or two strips off when I fly south in the colder months to keep oil temp in the ideal range. 

[Danb]

My acclaims heater in the winter is pretty weak at best, the Bravo was much warmer.

[Ragsf15e]

On 12/6/2025 at 12:05 PM, GeeBee said:

I have a mission that requires start up at 22 degrees F and landing at 46 degrees F. I will keep the airplane in a pre-heated hangar before start up. I have a factory installed winterization kit so I can install an oil cooler block off plate before departure. The AFM says I need to remove above 30 degrees. Can I safely fly the entire flight with the plate installed. I will be cruising around 10K and I am running 15W-50 oil.

@GeeBee, at least with my 252, it’s not really the ground temps that affect my oil temp, but the real cold temps aloft.  If you’re looking at -20c or so, Id put on the winterization kit.

[Will.iam]

In the winter even in texas i see -25 to -30 degrees when up in the teens most flights even though down at the ground it might be 45 degrees. When the air is as cold as 25 degrees there is no damp moisture in the air as it’s snow it it is. My dehumidifier never runs in the winter as the humidity never gets up past 35%. And if you are worried about your oil just put a dehumidifier on the engine after a flight to suck all that moisture out. My oil analysis is always the most dry from the oil samples i send in the winter. Summer are only a little higher unless i forget to put on my humidifier and take a sample this its the highest reading of the bunch. 

[GeeBee]

I arrived at my plane today and it was 18 degrees. So I put in the plate. I liked the way the airplane warmed up with it. Obviously it warmed faster but it stabilized quickly. Oil got right up to 180 and stayed there. Takeoff routine and after an hour or so at -10 oil went as low as 177 and as high as 183, but it was stable. It was too cold to run LOP. Landing temp was 37 but the oil stayed stable at around 177 to 180. I will use the plate again in cold temps, I think the engine is more stable thermally.