wsearl Posted January 28, 2008 Posted January 28, 2008 I have been reading the various posts about the appropriate time to make the change from mineral engine oil to synthetic, but haven't seen discussion about why it is necessary or desirable to do this. I asked my dealer what oil they use in hexheads (Castrol Activ4T) and, if and when they start using synthetic - the answer was that they continue using the mineral based oil. What is BMW's take on this issue and what do other owners think about it?
Mr_Ed Posted January 28, 2008 Posted January 28, 2008 You do not need to use synthetic but many do (myself included) after 18K miles. Since I follow the 6K interval for changing the engine oil I feel like using the synth adds a little piece of mind.
Ken H. Posted January 28, 2008 Posted January 28, 2008 Oil is a bit like religion, everyone has their strong opinions, so you will likely get a wide variety of responses, but my .02 - No.
Paul Mihalka Posted January 28, 2008 Posted January 28, 2008 I had a K75 with 200K miles, a K75RT with 130K miles, a R1100RT with 170K miles, a R1150R with 76K miles. All of them in perfect running condition when sold or disposed of. Non of them ever needed the cylinder head removed. All of them only with regular dino oil in the engine, but synthetic in the gear box for better shifting.
Boffin Posted January 28, 2008 Posted January 28, 2008 The only real advantage to using synthetic is its better tollerance of high-temperatures. If you live in a hot climate with heavy traffic and local laws that forbid splitting then synth is a good idea. I know Cairns would seem d@mn hot to a Pom like me, but as long as you can keep moving, synth may be overkill and an unnecessary expense. Andy
smiller Posted January 28, 2008 Posted January 28, 2008 No, it's not necessary. As Andy noted it may be a good idea if you operate in a climate or conditions where your oil temperature runs high as the Group III/IV (aka 'synthetic') oils do hold up better under prolonged high-temperature conditions (the other advantage being easier to pump at very low temperatures, but this is not usually much of a factor with motorcycles.) Many use synthetic regardless though just as a belt-and-suspenders safety net, whether that be real or imagined.
Boffin Posted January 28, 2008 Posted January 28, 2008 Translators note: US: Suspenders hold up Pants = UK Braces hold up trousers = Oz? UK: Suspenders are frilly ladies undergarments for holding up stockings [/hijack] Andy
Mister Tee Posted January 28, 2008 Posted January 28, 2008 I'm a huge fan of synthetics, and I use them in cars, motorcycles, and aircraft. How much of a benefit they are depends on the type of engine, and how hard you run it. Synthetic oil is probably the main reason why my gsxr 750 engine is still in new condition after 45,000 miles, having been run at near redline during much of its life. I suppose that a big, low-stressed boxer engine probably doesn't "need" it but I certainly plan on using synthetic oil on the RT once I have 10,000 miles or so on the engine. With synthetics, wear just stops. The only real dis benefit, except for the cost, is for engines that sit weeks or months at a time without running. Full synthetics tend to drain completely from metal surfaces over time, after which they offer no protection from corrosion. In fact, for that very reason, no full synthetic aircraft oils are made anymore - semi-synthetic oil is a compromise which offers some degree of corrosion protection. This isn't normally an issue for a car or motorcycle.
smiller Posted January 28, 2008 Posted January 28, 2008 Full synthetics tend to drain completely from metal surfaces over time, after which they offer no protection from corrosion. In fact, for that very reason, no full synthetic aircraft oils are made anymore - semi-synthetic oil is a compromise which offers some degree of corrosion protection. Everything I've ever read on the subject states that the primary issue when using synthetics in aircraft engines is a difference in the solubility of lead compounds, resulting in a higher possibility of lead deposits ending up in the wrong place and perhaps causing a stuck valve, etc. (not an issue in automotive applications of course since automotive fuels do not contain lead.) I've never seen anything to the effect that synthetic oil drains so completely that surfaces can corrode, or at least any more so than mineral oils. If so it's interesting... do you have any links that describe this effect?
Mister Tee Posted January 28, 2008 Posted January 28, 2008 Full synthetics tend to drain completely from metal surfaces over time, after which they offer no protection from corrosion. In fact, for that very reason, no full synthetic aircraft oils are made anymore - semi-synthetic oil is a compromise which offers some degree of corrosion protection. Everything I've ever read on the subject states that the primary issue when using synthetics in aircraft engines is a difference in the solubility of lead compounds, resulting in a higher possibility of lead deposits ending up in the wrong place and perhaps causing a stuck valve, etc. (not an issue in automotive applications of course since automotive fuels do not contain lead.) I've never seen anything to the effect that synthetic oil drains so completely that surfaces can corrode, or at least any more so than mineral oils. If so it's interesting... do you have any links that describe this effect? Ahhh that's correct too - I forgot to mention that. But yes, I can dig up links on the corrosion protection properties of synthetics as well.
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