View Full Version : cold weather operations, engine oil

11-05-2002, 07:18 PM
For people flying in cold weather, what grade of engine oil are you running? I have heard some say they switch to straight mineral oil in the winter.

11-05-2002, 08:52 PM
I have switched back entirerly to straight weight oils. 30 weight in the winter and 40 or 50 weight in the summer. I am just not sold on the 15/50W Shell. Everyone I know has said their oil comsumption went up after switching to it. Mine did. The shop I just had my engine rebuilt at said not to run 15/50 in it. Said to only use straight weight, so I am. Crash

Paul Persinger Jr.
11-05-2002, 09:13 PM
We run straight 30w in all of our aircraft (I work for a 135 op) in the winter here in Western Alaska. I have heard very favorable reports regarding the Exxon 20W50, especially the corrosion protection that it offers. I am considering putting it in the aircraft that I fly. I would not recommend the mineral oil.

11-05-2002, 09:44 PM
Aviation Consumer recently rated Aeroshell 15/50 one of the best oils out there and was not as impressed with the exxon for some reason I can't remember. I was running 100+ in the summer, but switched back to 15/50 for the winter, although it only gets down to 15 below or so here on a bad week in January.

I have been pretty pleased with the items I have chosen that Aviation Consumer has rated well, but an interested in other experiences - probably on another thread!


11-05-2002, 09:53 PM
I would recommend straight mineral oil 30W for winter 40 or 50W for summer. I DO NOT LIKE EXXON 20W-50. I worked in an engine shop and of all the engines that came in that did not make TBO used this oil. I know other factors come into play whether an engine makes TBO but the easiest
part to control is if you operate the engine and change the oil every 25 hrs without a filter and 50hrs with.


11-06-2002, 08:14 AM
I run 100 plus summers and 15-50 winters. This combo seems to work well especially during the transition months ( early spring, late fall). A long time midwest overhaul shop has taken issue with the 15-50 or any multigrade and will not warrant his engines with that oil usage.........but only in the high compression big bore engines.

Dave Calkins
11-06-2002, 03:41 PM

M1, do you really mean that you heard of switching to MINERAL oil for winter, or do you just mean STRAIGHT WEIGHT versus MULTI-GRADE?

AND.....get it right supercub 37! Unless alot has changed since the election, "...straight mineral oil 30W..." doesn't exist. A "W" preceding the weight means "ashless-dispersant" oil. Mineral oil is NOT "ashless-dispersant", and is most-commonly used as a break-in oil.

I do agree with your filter and oil change interval recommendation.

I'm guessing you guys just made some typo's, right?

By-the-way. I'm a straight-weight user, and recommend it for everyone.

With our temperature ranges, W100 (SAE 50 weight, ashless-dispersant) for summer. And W80 (SAE 40 weight, ashles-dispersant) for winter. For colder periods or areas, W65 (SAE 30 weight, ashless dispersant).

For break-in....manufacturers recommendation, or overhaulers recomedations, when a warranty is at risk.

Otherwise, for break-in, mineral oil until consumption has stabilized, then straight weight ashless-dispersant suitable for the temps.

In Anchorage, we could probably get away with straight-weight ashless-dispersant SAE 40, year-round, in Cubs. But Beaver's and the 6-cylinder Cessnas should run 50 weight for summer.

Check your engine manufacturer or builders recomendations, and stick with them. You don't need to second-guess the guy you trusted to build that thing.

Dave Calkins.

11-06-2002, 03:49 PM

I run 15W50 year round, but it does not get that cold here, -15C is coldest. This seems to work fine for me, oil consumption 5 to 6 hours per liter, running 180F to 200F engine oil temps. Oil change with filter change every 25 hours.

I was told some people running straight grade W100 not mineral oil in cold areas (as I first posted).

I thought the main reason behind the multi grades was to get an oil that would work well over a large temperature range.

11-29-2002, 11:17 PM
Straight wt. oils are the way to go in the high-cam lyc. engines. 40 or 50wt. in the summer and 30wt. in the winter, depending on temps of course. multi-vis doesn't leave a good coating of oil on the cam when hot at shut down, it is not as viscous as a straight wt. Depending on how often you fly, you may not have sufficent lubrication on the cam at start which has to wait for splash oil for further lubrication.

Dave Calkins
12-01-2002, 01:15 PM
Good point, Nanook.

And Welcome.

It will be nice to hear some opinions from another far Norther, along with Paul P. Jr.

Don't be shy.

Dave Calkins.

12-01-2002, 03:22 PM
The question I have is this: If you can maintain normal oil temp say 180-200 F while flying in the winter which oil should you use. Is 30wt better because you can have fluidity at a lower start up temp.pak

12-01-2002, 08:50 PM
OK just my 2 cents worth. If you can always preheat your engine (when it is cold), it probably doesn't matter what oil you use as long as you change it regularly and use the proper weight for the temperature(except mineral oil of course). I've used every kind in the book and have never had a problem with a Lycoming that was used regularly. Even 15-50 won't completely wash off a cam if you use it more than once a month. In fact that oil had the additive Lycoming added to the H2AD engines so it probably lasts a lot longer than that. I ran one engine for about 3500 hours on 15w50 and never had a problem with it. Even had to start it at 10 below quite a few times with no preheat. (it just happened to be an engine that would start at that temp. the ones I have in now won't). I finally weakened before the engine. It was running as strong as the day I overhauled it when I removed it.. I would never start any engine at that temperature with ANY other oil. However I have become a cheapskate and now use mostly Phillips 20/50 or a straight weight in the summer and switch to the 15w50 only during the coldest months of winter. The savings alone every 25 hrs almost pay for the overhaul if you can go 3000 hrs. I do agree that on 100 degree days the 15w50 would run closer to the redline.

12-23-2002, 10:00 PM
A point worth noting: If your engine ran on mineral oil all its life (after break-in), stay with it. DO NOT switch to detergent type oils.

12-26-2002, 07:02 PM
Aircraft oil isn't "detergent" but is ahless dispersent. AD oil keeps contaminants in suspension so they won't deposit in the oil pan and form sludge. According to Phillips' website, AD oils will not dissolve existing sludge, and it IS safe to switch from non-AD oil to AD oil at any time in the engine's life.

12-26-2002, 07:05 PM

I have been running 15-50 for years in 0-320's and have run several beyond TBO- the only problems encountered were unrelated to oil. The frequency of use is most critical and making sure that the oil gets up to temp. the 160hp I have now used to burn a quart every 8-10 hours and and that would increase when oil time got up around 20hrs. I have since added a spin-on filter and have run the engine another 100 hours. The oil stays much clearer (cleaner) and the oil consumption has averaged 10+hrs per quart. and I am changing it at 50 hours and maintaining 6qts in the sump.

Note: we get seldom into the 20's around here and in the summer the range is between 50-100f.

The biggest challenge I have seen is for those that seldom fly and then on occassion go out and "spin her through a couple of times" THERE LIES THE PROBLEM OF WIPING OIL OFF OTHE HARD PARTS!

Same goes for starting and "running for awhile" on the ground (frozen in on floats"?? This just causes the condensation level to dramatically increase and then rust to form!


Pre-heat if below 25F, Start- warm till oil comes up into the yellow, lean to best power, run at higher rpm, don't shock cool on decent, and fly more then everyone else you know!