Re: Motor Oil
Here are two questions that beg conjecture; I'm hoping they won't trigger opinions to the point that things start to slip, but if so, that's usually entertaining anyways...<br /><br />'89 4.3l cobra. Since I live in northern NC I tend to not winterize my boat (except for draining the water if there's any chance of a freeze) and running it occasionally throughout the winter. I make sure it doesn't sit for more than 3 or 4 weeks without running it.<br /><br />Given that I wanna have access to the boat throughout the year here are some of my thought/ questions. First off, this will be the first time I change the oil & outdrive fluid in the fall instead of the spring (learned the benefits of that from these forums). <br /><br />Specs call for 30w oil for temps >32F, 20w for 0-32F. I'll be running the boat occasionally in colder weather (probably 30-50F), but it also gets hotter here than many places during parts of the summer (air temps can get into high 90's & the water temp for the lake I live on can get up into the mid 90's). I'm thinking I might benefit from a multiweight oil to help with startup on some of those cooler days, and that a 'heavier weight' protection might be beneficial on those very hot days. <br /><br />I don't really want to change the oil twice a year as I put relatively few hours on the boat overall, very few during the winter. <br /><br />Say I went with a high quality 20-50. Seems like I would benefit during colder starts winter months. Also seems like the 'heavier weight range' might be helpful doe to the higher than normal air/ water temps in the summer.<br /><br />So much for possible benefits. I'm aware of the potential for polymer shear under heavy conditions with a multi-weight. But even if that happened, any guesses as to approximately what weight a 20-50 multi would 'settle' near if polymer shear should occur? Would it be near the high end, low end, or somewhere in the middle? <br /><br />If in the middle, seems like there would be little practical risk in using a multiweight for me anyways. First use would be during cooler weather, for very light use, presumably limiting risk of breakdown. Then into the summer months, where even if breakdown should occur, viscosity would be near recommended 30w anyways. Then new oil in the fall before it got cooler again. <br /><br />While we're at it, what about synthetic in an older engine? I saw a discussion about that on these boards, but couldn't relocate it when I tried to search. As I recall, there were questions as to the effect of a synthetic on seals & such in an older engine. I seem to recall someone saying that this was more of a problem when the synthetics first came out, & not as relevent any more, but that's just my impression (from a memory that is getting progressively worse as I age). Anyone willing to clarify that issue as well?<br /><br />Hopefully these questions won't spice things up TOO much, lol.
