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Oil - summer vs. winter.

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  • Oil - summer vs. winter.

    I know a lot of owners use straight 100W oil in the summer and switch over the 20w50 in the winter. Here in Maryland where the summers are pretty mild, I just use Aeroshell 20w50 all year round. Any thoughts or experiences on weights or brands?

  • #2
    We use 100W in the summer and 80W in the winter.

    I assume there's a viscosity difference but don't really know much about it.


    • #3
      Up until now, I've used Aeroshell 100+ in the summer and Aeroshell 15w50 in the winter.

      However, both the Tcraft and the Citabria have had minor oil leaks with the 15W50 that seem to dry up when I switch to 100+. Consumption (or more likely venting out the breather) was always a little higher in the Summer. Since the engine in the 170 has absolutely no leaks now, I was afraid to switch over to the Aeroshell 15w50 this winter. I've heard very good things about Phillips 20w50, and have spoken to several A&Ps who run it in their own aircraft year round. So, when it was time to change the oil last week I swapped to the Phillips.

      We'll see what happens. Regardless, I don't plan on going back to the Aeroshell 15w50.


      • #4
        We use AeroShell 15W-50 multigrade in the winter months and switch to AeroShell Oil 100 (perhaps PLUS) single grade in the summer months.
        I just use Aeroshell 20w50 all year round
        BTW, are you sure you use Aeroshell 20W-50? I'm not sure they have a 20W-50 oil for piston engines.

        Here's some related info from the Aeroshell website regarding the 15W-50 vs. 100:
        Do AeroShell Oil W 15W-50 and AeroShell Oil W 100 perform the same in an engine?

        The oils are similar, but there are some differences. The biggest difference is in cold flow characteristics. AeroShell Oil W 100 is up to 10 times thicker at cold temperatures than AeroShell Oil W 15W-50. However, at normal operating temperatures (around 200°F), both oils will have the same thickness or viscosity. Another major difference is that AeroShell Oil W 15W-50 and AeroShell Oil W 100 Plus have an antiwear additive which is not in AeroShell Oil W 100. This additive, along with the semisynthetic base oils, helps reduce friction and improve flow in AeroShell Oil W 15W-50. These additives improve lubrication and reduce oil consumption past the oil rings. Conversely, the improved flow can increase oil loss through leaks or loose intake valve guides. So your oil consumption may go up or down if you switch from AeroShell Oil W 100 to AeroShell Oil W 15W-50. The improved flow and reduced friction characteristics of AeroShell® Oil W 15W-50 will also help reduce oil temperatures as opposed to using AeroShell Oil W 100. This is particularly important in engines that run hot, like turbocharged, high performance or aerobatic aircraft engines. Pilots should always remember to monitor oil temps to ensure that they’re not too hot. In cold weather, you should also make sure that the engine temperature is high enough to boil off the water that naturally accumulates in the crankcase. Temperatures in the 180° to 200°F range are recommended for most applications. Finally, if you have a marginal or slipping starter clutch, the antiwear additive in AeroShell Oil W 15W-50 may cause it to slip more than AeroShell Oil W 100. Understanding these differences can help you select the grade of AeroShell that's right for your plane.
        Last edited by Jeff S KDTW; 11-16-2005, 14:34.


        • #5
          There are some reported problems using the the Aeroshell semisynthetic 15W50 with the Lycomings. This oil flows so well, that it will completely drip off of the cams on the lycomings and cause excessive wear on startup. Unless you operate your aircraft several times a week, I would recommend Phillips 20W50 over the synthetic oils. The Plus in the Aeroshell, and Avblend are good additives to help reduce startup wear.


          • #6
            100 in the summer 50 in the winter for me.


            • #7
              AeroShell 15W-50 year 'round...


              • #8
                After the initial application of mineral oil, I've used only 15w50 (you're right Jeff). But, I kept it in a heated hanger last winter and will probably do so again this year as well so cold starts haven't been an issue. If I'm starting up after it's been sitting out in the cold a while I'll manually turn it through a couple of turns before cranking it.

                Also, thanks for posting the Aeroshell note. That jives with what I knew about multi-viscosity oils as well including the additives in the 15w50. So the question is, why would you run the straight 100w in the summer if, as it says, the performance is about the same at operating temps? I'm guessing it's cheaper but is there any other reason?


                • #9
                  Originally posted by WesJones
                  So the question is, why would you run the straight 100w in the summer if, as it says, the performance is about the same at operating temps? I'm guessing it's cheaper but is there any other reason?
                  I'm no engineer, and I didn't stay at a Holiday Inn last night. That being said, the 15W50 leaked out of two differnt engines of mine (Lyc 0-235-L2C and Lyc 0-320-E2D). When I switched over to 100, the leaks dried up. Small leaks yes, but still annoying.

                  I can't explain it, but I don't like preventable leaks. That's why I switched over in the summer.


                  • #10
                    We used to run 15W-50 year around in the Grumman (O-320). Never had more than a few ounces of metal shavings in every oil change...


                    • #11
                      I use phillips x country 20-50. If I'm not mistaken that is what most of the major engine rebuilders and continental are recommending for the big continentals.

                      I know several people that have used it to break in and run to full TBO with it on o-470's and o-520's.



                      • #12
                        Originally posted by Mark Lander
                        100 in the summer 50 in the winter for me.
                        Thats what I did in my 172.



                        • #13
                          Ok, but not having any leaks that need stopping up in the summer myself, I'm still wondering if running 15w50 isn't better because of the additives.

                          On a separate note, I've seen independent analysis in Aviation Consumer that the Exxon Elite oil is actually the best for engines that sit up for longer periods in that it has an additive that keeps moisture in suspension and cuts idle engine rot substantially. I just can't bring myself to change having had really good results with Aeroshell for a lot of hours.

                          It might be interesting next summer to try the 100w for a few hours and see if it makes a difference on the oil pressure in zero G situations (flat spins for example).



                          • #14
                            100w plus year around. A cold winter for here dips into the 60's though.


                            • #15
                              Originally posted by JimJenson
                              A cold winter for here dips into the 60's though.
                              That's painful--I won't see 60's again until about March or April.