I was just wondering if anyone could explain to me why Synthetic oil is not recommended for brand new vehicles, but only once break-in has occured.<p>If I understand the vitues of synthetic oils correctly: longer effective life, better dirt absorption and removal, less likely to cause hard buildup, more easily transported to critical areas during cold starts, friction reduction, etc....<p>With all those things going for it, why would you not use it at break-in time when a majority of heavy friction heat reduction and dirt collection is most called for. Wouldn't the same qualities that make it such a good lubricant for post break-in use be doubly important at the very start?<p>

Synthetic is not recommended during the break-in period because a certain amount of controlled wear is necessary to allow the piston rings to seat. The properties of conventional oil are much better suited to piston ring seating and allowing gaskets to "swell" for a perfect fit. <br>

...just follow your advice below, voice of reason.

Dino oil will allow some wear to occur between the rings and the cylinder walls, allowing the rings to perfectly match the walls (much like new brake pads seating against a brake rotor; have to wear them down slightly to get the pad totally following all the little contours of the rotor). id this doens't happen, get blowby past the rings and heavy oil consumption.<p>That's my understanding.

But now it's you who doesn't get it. I am just trying to understand the nuances of different oils and why one is supposed to be better than the other. Not how often I should change them or how thin or THICK (in your case) they ought to be. <p>Go pick a fight somewhere else....

Ray Calvo is right.. but if that doesn't satisfy your curiosity, I suggest you visit the API website. They are the governing body of motor oil - they set the specs, they coordinate on the tests, etc. They have a bunch of consumer-oriented publications which will tell you way more than you ever wanted to know. In addition, all the motor oil websites have FAQ sections and "contact" areas where you can email in very specific questions about m.o.

Yes, I get it. I provided information that you were not looking for. You did the same thing below (I did not ask for a lecture about oil change intervals, cost or performance increases). Glad to see that you do not like that type of response either.<p>I can't answer your question directly other than to say that Corvettes and Porsches do come from the factory with Mobil 1 in them. So in some cases it might be alright to use synthetic oil during break-in. Maybe it depends on the engine design/manufacturing process/materials. Maybe the manufacturers are not willing to test or certify that using synthetic during break-in is OK. I just don't know the answer. I believe Julia works in the oil business, and her explanation is the one I have always heard. The following link has some information on the properties of synthetic and conventional oils that might be of some help to you:<p>http://www.vtr.org/maintain/oil-overview.html<p>There used to be a FAQ about Mobil 1 on their www site, but I was not able to find it there now. I remember there being a statement in it regarding using Mobil 1 during break-in.<p>Personally, I never understood the argument that with synthetics that the rings would not seat. If not, then why not throw in some conventional oil next time to let the rings seat then switch back to synthetic after that?<p>Sorry, but I'm really not trying to pick any fights.

Not to sound like I'm picking a fight, but my take has been to follow the manufacturer's recommendations to the letter for the first change - i.e. don't second guess the engineer's recommendation - even if the local oil jockey has been changing oil for 20 years and says otherwise.<p>Then switch to synthetic after the first change.<p>Often is the case that manufacturers will add break in additives to the factory oil when shipped (whether this is the case for the A4 has been argued here before). You won't be helping your engine any to loose these additives to switch to synthetic early. <p>** A little aside: I read a test drive article about the MB SLK. The SLK has a engine oil analysis system that recommends when to change the oil (based on oil quality, driving conditions, etc.). Based on its recommendation, the *first* change was at 12000+ miles. The oil at this point was found by a lab to still be within spec. This would cause the local oil jockey to have a fit. However, he only wants your money... and his "wisdom " is based from a time when cars didn't always have oil filters and oil quality was no where near what it is today.<p><br>Your mileage may vary,<br>Dwayne<br>94 S4

It was not my intent to lecture you (or anyone else) either. <p>I was just expressing an opinion - perhaps a bit too strongly. <p>I agree with you re: Julia. She makes alot of sense. <p>Anyway, a family friend is a mechanical field engineer/designer for an airplane manufacturer (Bombardier). He has a lifetime of experience (30 years) with these types of issues regarding engine wear. He influenced me with his experienced point of view regarding engines and oil. <p>Bottom line (his and now mine, I guess). Keep the engine clean by replacing oil (and filter, natch!) more rather than less frequently and it will serve you well for many more years. He does not think that synthetic oils are worth the extra cost if you replace the regular oil regularly (for most people this just happens to be around 3000 miles). However, that's not to to say that synth oils are bad or do not have appropriate applications. I am just trying to educate myself on their uses and benefits/characteristics without applying for a degree in chemical engineering.<p>Drive Safe.<p>

Oil, as you can see, is a very emotional topic to a lot of folks! Sorry if I was a little rash.<p>Since we're on this topic now, I agree with most of your and your friend's points, but I feel that there is a 'point of no return' in changing your oil more frequently (similar to the thought that spending more on synthetic is not worth it in some cases). What that 'point of no return' is depends on driving conditions, driving habits and the quality of the oil and filters used. I agree that if you are using conventional oil, early changes are cheap insurance. However, I feel comfortable extending my oil changes to 7500 miles/6 months (free service intervals under the Audi Advantage program) due to my use of synthetic oil.<p>From what I have read, synthetic oils resist viscosity break down much better than conventional oils, and they contain less additives (sometimes none) like viscosity enhancers and pour point depressants than their conventional oil counterparts. This is partly what helps them to last longer, as it is the additives that are the first to give up the ghost. The higher coking/flash points and lower pour point temperatures of synthetic oils are well documented (enter Mobil 1 dualing banjos commercial here). These are highly desireable benefits for a high-reving, hot-running turbocharged engine.<p>Now, for real-world experience in using synthetic oil, here is what I have noticed since I switched to Mobil 1 in my 1.8t:<p>- the engine runs a little more smoothly and quietly<br>- the engine seems to rev a little more freely<br>- during near freezing temperatures, the engine cranks much easier (meaning the the oil is flowing better, and getting to the turbo and overhead cams more quickly)<br>- the engine oil temperature has gone down several degrees<br>- the oil stays cleaner looking (does not darken as much as conventional oil does)<p>In addition, I have not seen a gas milage increase, but a friend that put Mobil 1 in his EB Expedition has seen a mile or so increase (but he is using a much lighter weight than 15w-50).<p>I am pretty much sold on synthetic oils, and fortunately the added cost is not an issue for me (given my experience with it I could justify the higher cost anyway, so I would find a way to afford it if it came to that). Now if I did not have a turbo or a high performance engine I might not use a full synthetic oil, but I would consider a synthetic blend. If I transfered to a cold climate I would use synthetic oil.<p>Hope this helps.

how often do you change your oil?<br>

My Audi sees a fair bit of track time, I change the oil 3 times a year. Once at the start of the spring track season (changing this weekend). Again half way through the summer (after about 8 days on the track). Then once in the fall at the end of track season with a lighter oil for winter. I likely don't need the mid-summer change and will probably have an oil analysis done to check out that theory. I run Mobil 1 10-30 in the winter, and 15-50 in the summer (will likely run 10-30 all year from now on). I only put about 20,000 km on my Audi per year.<p>On my other car (Legend coupe that my girlfriend drives to work), the oil is changed per Acura's recommendation every 12000km (7500 miles). However I use conventional oil in this car. 255000km and counting, all original, new clutch at 235000km.<p>Dwayne<br>94 S4

GM uses Mobil 1 in the Corvette because Mobil pays GM low seven figures each year for the privilege of saying that Mobil 1 is the factory fill on Corvettes!

nt<br>

<br>nt

...especially the fact that your oil temp has dropped with synth. It certainly says a lot about reduction of frictional forces. Add to that the better cleaning properties of synth which I have read about and I am convinced to try it on my S4 - if it ever shows up. I still think that 7,500 is too long to wait between oil changes so it looks like I'll be spending alot more on LOF in the future.... not that there is anything wrong with that!<p>Happy motoring.<p>

The views expressed in this series of postings are my own. I do not express, nor do I claim to express, the official or stated position of Mobil Oil Corporation (or of any other legal person) with regard to marketing structures, alliances. or business transactions of any nature.

This type of advertising is quite the fad now. The Mobil 1 arangement seems very similar in nature to me. And us consumers will be the ones who pay for it!