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Synthetic Oil Vs. Regular Oil?

11K views 27 replies 12 participants last post by  FruityOne 
#1 ·
Ok, i got a 1992 325i. Which oil is best to use? Synthetic or Regular? Any specific type my car will like better? Im not gonna sweat price's. I just want whats best. Thanks in advance.
 
#3 ·
It all depends on the miles on your car, and the type of oil it is using already. Usually they say if you are over 30,000 miles do not switch to synthetic. You can still use a high grade regular oil.
 
#6 ·
just wow....*shakes head at responses*

definitely synthetic it will keep your engine cleaner
 
#8 ·
Originally posted by ///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.
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please explain to me how synthetic oil would make you have trouble with your engine internals?
 
#9 ·
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.
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please explain to me how synthetic oil would make you have trouble with your engine internals?
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[/b][/quote]

I wanna hear that too.

There are no arguments that hold for using regular over synthetic other then maybe cost of the oil.
 
#10 ·
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.
 
#12 ·
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.
 
#13 ·
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.
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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.
 
#14 ·
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.
 
#15 ·
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.
 
#16 ·
Originally posted by CountChuckula@May 3 2005, 02:39 AM
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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With 195,000 miles on the car do not switch to synthetic. It will cause your car to leak. The build ups that were reffered to in earlier posts are reffering to impurities in the oil that actually end up clogging leaks. When you switch to synthetic it will break down the "cloggs" and then your engine will leaks oil. With the mileage yours would pretty much leak about as fast as you could keep oil in it. Unless you are very luck. If you can't tell which you had, synthetic or regular, then just put Castrol GTX in. It is a great oil.
 
#17 ·
I bought my 98 M3 and it had 62,000+ miles on it. I have no idea what oil was used before but I immediately changed it and always change it myself using
Mobil 1 synthetic oil. I have no run, and at time very hard, 15 thousand miles on the car and I have no found one leak. I also have a 1986 735i with over 227 thousand miles on it. It is now finally starting to smoke some white smoke, but then again it sat for 18 months without running too. I prefer and reccommend Mobil 1, but to each his own. Anyone have a recommended oil filter???? I am curious!
 
#18 ·
why would you want your engine gaskets and seals to be held together by impurities? i mean really so what you use synthetic oil and it cleans out deposits and you have to replace a few gaskets...i dont see what the big issue is with replacing a few gaskets that were being held together with engine deposits unless you guys are some seriously cheap bastards.

someone please enlighten me
 
#19 ·
Originally posted by Fruityone@May 4 2005, 02:30 PM
why would you want your engine gaskets and seals to be held together by impurities? i mean really so what you use synthetic oil and it cleans out deposits and you have to replace a few gaskets...i dont see what the big issue is with replacing a few gaskets that were being held together with engine deposits unless you guys are some seriously cheap bastards.

someone please enlighten me
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ive never had issues with synthetic oils in my bmws, i purchased my bmws with 145k, 135k, and 189k respectively and switched to castrol syntec 10w30 the second i purchased them and i never had any leaks.. ive seen alot of mustang owners have leaks after switching to synthetic, but never had an issue w/ any of my bmws...

i also run in arizona, and run hard... temps in the summer are in the 120's... never a problem.


and, if you do leak due to using a higher quality oil, and dont switch out your leaky gasket, you are cheap.. go buy a honduh.
 
#20 ·
the pros: cleaner engine

cons: gaskets need to be changed due to deposits being removed

i dunno makes sense to me...unless you guys are talking about synthetic oil causing your engine block and cylinder head or something to leak...in which case your block and head are cracked and deposits wont hold that together.
 
#21 ·
Ok so what I'm seeing here is someone telling me that engine deposits are good, because they plug holes in leaky seals. That's like saying that termites aren't a problem because the cancer causing lead based paint is holding the goddamn wall up.

Look, I don't know what planet your mechanic comes from, but I'll be damned if he's coming anywhere near me or any BMW or Porsche that I'll ever own. Engine deposits are bad. Very bad. Why do you think we have oil filters?

Just to drive the point here home, let me quote you directly from the motor oil bible (my latest read)

If an engine does not remain clean, it doesn not remain efficient. Deposits within an engine gum up the works and reduce fuel efficiency while robbing your engine of performance. In addition, contaminants within an oil that are left "unguarded" can cause incalculable wear within an engine.

Any particle larger than 5 to 20 microns in size (depending on the vehicle) will seriously damage an engine if not removed. To give you an idea of how small this is, a human hair is 100 microns thick. Although filtration plays a big role in this area, the oil also has to play it's part by keeping deposits from forming within the engine and by holding contaminants in suspension until they can be removed by the oil filter.
So in other words... if you think that engine deposits are helping you, you're a fucking moron. 5-20 microns thick... do you think that's enough to stem the flow of oil from a fucking leak? No.

To settle the regular oil vs. synthetic oil dillemma, I refer you again to the first chapter of the Motor Oil Bible:

In fact, the relationship between [synthetic and petroleum basestocks] would be similar to the relationship between a big rock and a hammer. Both can be used to drive nails, but one will be far more effective than the other. A hammer which is designed for driving nails will do so far more efficiently than a rock.

In addition, the hammer will be able to drive nail after nail without any significant loss in integrity. The quality of the hammer will degrade very little over time. However, the rock will be easily chipped and cracked when used to pound nails. In fact, you would probably find that after only a few dozen nails, you would need to go find a new rock to pound nails with.

You see, the rock was not designed to pound nails. Of course you could fashion it into something that looked like a hammer if you like, but it's still a rock. It will work in a pinch, but it is not the right tool for the job.

But along comes "Nail Drivers Inc." with a novel idea. They decide to first determine what the qualities of a good "nail driver" would be. Then they fashion a tool that is specifically designed to have these qualities.

Doesn't it make sense that the new tool will accomplish the job far better than the old rock? The same is true of a synthetic oil when compared to a petroleum oil.
Ok. Get the idea? A fucking expert on oils who wrote a book called the "Motor Oil Bible" thinks that synthetics are better. What the fuck more do you want to know?
 
#22 ·
no no no jason oil filters are so people can make money selling parts and to decorate your engine bay.

in case no one picked up my thinly veiled sarcasm...i was being sarcastic
 
#24 ·
hmmm mine must be special edition...it has rhinestones and sequins and glitter on it....maybe i should get the filter chromed?

again refer to my previous statement about thinly veiled sarcasm...theres too many idiots on this forum that might take me seriously and blame me when their engines blow up from doing something like what i was JOKING about.
 
#25 ·
i had an old range rover i off roaded for years and put the old mobil 1 oil from my audi S4 into it (after it had done about 10k in the audi), bearing in mind, that old v8 rangie had done 150k miles when i started using it, i never changed the oil again and never had any leaks or problems for many years of revving the bollocks off it, overheating it, swamping it under water etc etc and its still going strong today.. so i had no second thoughts about putting mobil 1 into my bmw as soon as i bought it! and touch wood, i aint seen no leaks yet! :driving
 
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