Originally posted by Fruityone+May 2 2005, 11:56 PM--><div class='quotetop'>QUOTE(Fruityone @ May 2 2005, 11:56 PM)</div><div class='quotemain'><!--QuoteBegin-///M Power@May 2 2005, 02:26 PM With such an old car, probably a decent amount of miles, and probably not wantign to replace or start having troubles with the internals.....
...regular would be ideal. Check it often and make sure to change it regularly.
please explain to me how synthetic oil would make you have trouble with your engine internals?
I wanna hear that too.
There are no arguments that hold for using regular over synthetic other then maybe cost of the oil.
Ok. Some of you here are very confused about the difference between synthetic and regular oil. Instead of just telling you that you should probably run regular oil, I'm going to tell you what oil and why.
First of all. Those of you who think that all synthetic oils are actually synthetic, you need to shut the hell up right now. The fact of the matter is that many of the cheaper synthetics are actually regular oils that have been processed so much that they are closer in their properties to a synthetic oil than a regular oil, but they were still refined from crude. Many "synthetic" oils and many "blended" oils are just highly refined crude oil. Now don't read this to mean that they are low quality. The hydrocracking process is so good at removing impurities and creating a good base that it meets the minimum quality standard of synthetic oil.
Now as for the specific properties you're looking for in an oil in a super high mileage engine:
1. Start up protection in cold weather. This is directly related to the pour temperature and the viscosity of the oil. For this, you want a double weight oil that has low viscosity at low temperatures and a very very very sub zero pour temperature, so that the oil still flows well enough to get distributed while the engine is turning over. Keep in mind that most of the wear that your engine will recieve internally will be during start up. This is about the only time (aside from a gunshot in your oil pan) that you are going to have metal to metal contact, so you want to keep that to a minimum.
2. Clean burning properties. Plain and simple, no synthetic burns off clean. Ever. It just doesn't happen. If synthetic burns at all, it burns into sludge. It's designed not to burn, so pretty much no engineering thought went into how it would burn. You want a good high quality natural oil (aka certain blended synthetics) or a synthetic that's so high quality that there's no chance in hell it'll burn. You really only need to deal with this problem once your engine crosses the magical 200k miles barrier. Once that happens, you can expect that your rings aren't sealing as well as they used to and from time to time oil will sneak into the combustion chamber. If you use a synthetic, chances are it will make a deposit of some kind, whereas a regular oil will just burn off and make your exhaust smell like ass.
This pretty much eliminates all regular oils that aren't marketed as "blended" or "synthetic." Castrol GTX is the best regular oil for older cars out there. If you can afford it, though, a super high quality synthetic is the best. I reccommend Lubromoly since it's a BMW motor and I've personally had very good luck with it. Now if you run GTX, remember that it's a regular oil, not really a blended synthetic. It's just very highly refined. On a motor oil like that, it's great for when you're driving around town not pushing hard, but it won't adequately protect your motor if you're going to be racing it around all the time. It's resistance to frothing is not very good so high RPMs for sustained periods of time are a no no. If you're going to do that, switch to a heavier high quality full synthetic and go on about your business.
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The main thing I have been told by numerous people is that a synthetic typically has more detergents in it or stronger ones. This can be a problem when switching if you have higher miles because of oil buildup that may get "cleaned" out and cause leaks. It seems to me that as long as you choose the right type of oil for your driving, weather, and miles you will be fine with regular oil or synthetic.
Originally posted by jshearer@May 2 2005, 06:08 PM The main thing I have been told by numerous people is that a synthetic typically has more detergents in it or stronger ones. This can be a problem when switching if you have higher miles because of oil buildup that may get "cleaned" out and cause leaks. It seems to me that as long as you choose the right type of oil for your driving, weather, and miles you will be fine with regular oil or synthetic.
if im not mistaken...getting rid of buildups is good. and as far as cleaning out buildups causing leaks...that just means you had a problem waiting to happen if you had gaskets that were being held together by engine deposits.
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Use synthetic then, I personally will listen to the BMW mechanics and my old Porsche mechanic. If you get the right kind of oil it doesn't really matter. I am just not going to switch to synthetic after 80,000 miles on regular oil.
Switch to ethanol blend gasoline while you are at it, it is supposed to be cleaner too.
Thanks a ton everyone. I really apreciate the feedback and explinations. Is there anyway to tell what kind of oil the previous owner used? I know this may be a STUPID question, but its got 195,000 miles and I dont wanna switch it to anything bad. If it comes down to it, and theres no way to tell, can i get it flushed and switched to the best? Thanks again. I love you all.
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