Winter oil weight

Huckster79

Huckster79

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Huckster79
get the popcorn!

I fly a 47 Cessna 140 with a c85, but principle should fit most GA pistons I would think:

This spring I switched to shell 100 plus... I like it as I’ve found it “sticks” way up my dipstick.. that I can check it cold it’s at 6, wipe it off redip will show 5, preheat it and it’ll show 5 3/4... so I interpret this as that thick 100w stuck to my dipstick higher than the sump level and stayed there...and when I preheat and get it hot it drips more down from all over for the increase...

When I used the multi weight oil level was same on stick when checked cold even after a wipe and redip.. I’m thinking it didn’t so much stick around...

If I’m a religious preheater, there’s no reason I can’t run the 100w all winter is there? I am in MI so it’ll get cold...
 
100 in Michigan in winter is not a good idea. If you are going to use a single grade 60 is what you should use, but multi grade is better. When you start you want that nice warm oil circulating freely in the engine.
 
When you "redip" it are you screwing it all the way down?

When I was researching it I found a report of a test that the residual film thickness on vertical surfaces was the same (.001") for single and multi weight oils. I was using W100+ in my O-290 since I don't fly when it's below 40° but now that you can get it with the Lycoming anti-wear additive I'm going to switch to 20W50 with Camguard at the next oil change.
 
I've been using xc20w50 for years. When I had my engine overhauled, the shop commended the use of this oil. Plus I don't have to give it a second though when the weather changes.
 
In climates with temperature extremes, just go with multiweight oil, Aeroshell 15W50 or Philips 20W50 and don't worry about temperature changes. Optionally add CamGuard to suppress corrosion. Preheat below 30F or so. It is not recommended to run heavy weight oil in winter temps.
 
Engine manufacturers publish oil viscosity recommendations for different temperatures. Read them.
 
Of course we all understand that Shell W100 and W100 plus are SAE 50, not 100, right?
 
wrbix said:
Of course we all understand that Shell W100 and W100 plus are SAE 50, not 100, right?
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Yup, and SAE 50 is pretty thick stuff.

Do what I used to do in my aircraft systems class. I took quart containers of several different oils such as 80, 100, 15W50 and put one of each in the freezer overnight and another of each in a pan of hot water and kept it simmering on the stove to get the oils up to about 210°F or so. Another of each oil was at room temperature. Then I'd take the 80 room-temperature oil and pour some out on an aluminum ramp in a pan so they could see how it ran. Took the hot 80 and poured it out and it ran like water. Took the cold 80 and poured it out--barely--so they could see how low temps vastly increased the viscosity. The real shocker was the cold 100: like molasses in January, and that was only at freezer temps, which are typically only about -10°C, warmer than some cold days. I'd ask the class how easy it would be to suck that stuff up a 1/2" straw like a milkshake, and told them that's what the engine had to do in the winter, and why we didn't run heavy oils in winter. The 15W50 thinned with heat and thickened with cold, but the changes were much smaller, as they should be. It acts like a cold SAE 15 when cold and a hot SAE 50 when hot.

In cold weather the oil temp might not get high enough to keep 100 (SAE 50) thin enough for the pump to keep the engine happy, no matter how much preheating you give it. Cold air doing 100 MPH sucks the heat out of stuff real fast. Lots of engines have been trashed by the wrong oil at lower temps.
 
What I've been told is this: "run a mineral based 20W50 in the cold months and Aeroshell W100 the rest of the time. If you're flying long enough and often enough to keep your engine clean and you keep your airplane hangared when not flying, corrosion worries are likely pretty low, and you can run multi-vis year round."
 
IK04 said:
W100 blows a lot of oil mist in cold weather on the C85, unless you have the case vent mod.
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So in your experience you agree with the 20w50 in the c85 in cool temps?

In winter even with winterization Kit I rarely can get 180 degrees, it’s north of 150 but south of 180 if I recall right from last year
 
OK... time for another whole can of worms...

Ex-partner (who is also an ace auto mechanic) insisted that synthetic oil was better for our engine (Lycoming 320), while my A&P cautions VERY strongly against using synthetic. I use Phillips XC 20W50 and listen to my A&P. My ex-partner thinks I'm nuts. What is the downside of using synthetic? My A&P's explanations were unclear to me... but a lot of things are... it ain't his fault.
 
You mean smi-synthetic? That's limited to Aeroshell 15-50 these days. It has better cold temp pouring viscosity than other oils including Phillips 20-50. The downside of synthetics was it can't scavenge lead. Google Mobil 1 in airplanes. Aeroshell is a blend of synthetic and mineral oil so it only sucks half as bad as Mobil did. ;) Semi-synthetic oils are more prone to oil leaks and blowby, too. Some will argue that but it's 100% true in my airplanes.

Aeroshell 100 and Phillips X/C are mineral oils with AD additives. Aeroshell's Plus oils add scuff and corrosion additives but the base product is still mineral oil.
 
Unless you live in a place that is always warmer than 60-70f, a multi weight oil is ALWAYS going to be better. The oil pumps faster to critical parts on start up. Most wear happens at start up. Unless your running 300f oil temps the straight 50w does no better that the multi weight oil.

Actually the multiweight protects better in slightly over temp conditions because the oil has viscosity modifiers so as it gets hotter it actual thins at a slower rate than the straight weight.


Sent from my iPhone using Tapatalk Pro
 
Stewartb said:
You mean smi-synthetic? That's limited to Aeroshell 15-50 these days. It has better cold temp pouring viscosity than other oils including Phillips 20-50. The downside of synthetics was it can't scavenge lead. Google Mobil 1 in airplanes. Aeroshell is a blend of synthetic and mineral oil so it only sucks half as bad as Mobil did. ;) Semi-synthetic oils are more prone to oil leaks and blowby, too. Some will argue that but it's 100% true in my airplanes.

Aeroshell 100 and Phillips X/C are mineral oils with AD additives. Aeroshell's Plus oils add scuff and corrosion additives but the base product is still mineral oil.
Click to expand...

When I managed the flight school maintenance we used to use 80 or 100 in the summer and 80 in the winter. Then we started using Aeroshell 15W50 in the summer, and then I decided to run it year-round. This was on the Canadian prairies, where summertime temps reached over 90°F and we'd take off in the winter down to -25°C (-13°F). That 15W50 was good stuff, and the engines (all Lycs) reached TBO without any trouble at all, compressions still in the mid/high 70s, and the oil consumption was low. Oil pressures were good even in the summer. I tried that 15W50 in my A-65 and saw the oil temperature drop as much as 30 degrees. It's slippery stuff. And those engines didn't leak.

Before that we had a couple of 150s and I found that the O-200 would use more multiweight than a straight-weight oil. No good reason for that, but there you go.
 
Be sure to also talk to your AP about swapping over to winter air for your tires too, saftey first!
 
MuseChaser said:
OK... time for another whole can of worms...

Ex-partner (who is also an ace auto mechanic) insisted that synthetic oil was better for our engine (Lycoming 320), while my A&P cautions VERY strongly against using synthetic. I use Phillips XC 20W50 and listen to my A&P. My ex-partner thinks I'm nuts. What is the downside of using synthetic? My A&P's explanations were unclear to me... but a lot of things are... it ain't his fault.
Click to expand...

He’s wrong, the molecular structure of fully synthetic and the lead in 100LL do not play nice together. It will not suspend the lead and it will deposit where you do not want it. The 15-50 has some synthetic in it.
 
In my planes (4 different engines) it appears semi-synthetic 15-50 allows more blow-by than X/C. 15-50 definitely drools more from the breather. It also changes color to dirty gray by oil change time. X/C reduces breather drool and oily belly and is much cleaner at change time. Test it yourselves.
 
I run 20w50 all year round and just pre-heat when overnight temps are below freezing.
 
Clean oil makes me nervous.
I want my oil to be cleaning engine deposits, thus getting itself dirty.
 
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