I am going to the dealership tomorrow for my first oil change(1000 miles). When I first picked up my car I was told by the salesman that it had synthetic oil in it(mobile one)....I am not sure he knew what he was talking about. Is that common for the car to be delivered with synthetic oil from the start? More importantly if I have them put synthetic oil in tomorrow for my first oil change is that alright if regular oil is in it now or do I have to do anything special to change over. I do not want to do any damage to my car. Please help me with what I should do here...

 

I HIGHLY doubt it was synthetic. unless they drained the oil that came in it from the factory and replaced it themselves with synthetic. in which case, they are pretty dumb, as almost everyone agrees dino oil is best for breakin as synthetic offers TOO little friction, and nothing breaks in.

as far as switching; nothing needed; tho Id maybe suggest you stay with regular oil for another change; just to complete the breakin, then switch to synthetic at 3000 or whatever.

 

My dealer suggested for me to wait till 10,000 miles or so to switch over to synthetic. Regular oil is better for break-in so I am told. I will be changing my oil at around 9,000 miles at which time I will opt to switch to synthetic. BTW, just in case you were not aware, once you go synthetic you cannot go back to regular.

 

Thank you for responding........When I called the service dept they were not helpful with this. I am really trying to do what is best for the car as I plan to have it for many years...all your help is appreciated as I do not know very much about this.

 

350zluvr,

Can you explain why you can't go back to regular? I've heard this many times before but I never got an explaination as to why this is the case.

Thanks.

 

My service manager also said wait before using synthetic as the "valves are very hard and take awhile to seat-in" He said 12000 miles would be about right so I'm changing oil every 3,750 until 12,000 then going to Mobil 1 5w-30.

 

I was told 10K from dealer before going synthetic but then others have done it sooner. I'm just about there and I would only recommend mobile one. Just preference I guess since I've been using it for years.

 

You can go from synthetic back to regular oil...your engine will not blow or anything LOL.

 

I switched at 8500 miles. BTW, make sure you run 5W-30 during the cold months.

eachtau, my advise is to go back to the dealership and find the same salesman if you can. Have a frank conversation with him explaining that it is a big deal that you know what kind of oil is in your car for maintenance reasons. Ask him if he is 100% sure, he will hopefully say, no, I really am not sure.

This is because there is a 99% chance that this **ckin idiot lied to you like so many moronic retarded, wannabe know-it-all salesmen do. Chances are very good that you have regular petrolium based motor oil in your car now...as you should.

Maybe there is a way to test a small sample?

 

A BMW mechanic told me the same thing.

 

Eh, not to be a jack a$$ here, but it seems like no one really knows rather if you can go back and forth between synthetic and regular oil.
Yobri, did you ask the bemmer mechanic WHY?

ANY ONE KNOW WHY? AND HAVE A FULL EXPLAINATION? Preferably with some kind of chemistry back up.

Once again, not to be a dick, this is something I really wanted to know.

 

My future cousin-in-law works for SF BMW, so every time my g/f meets her family, me and him shoot the sh*t. One day, we were talking about my restoring my old Civ... well this one mechanic awhile ago had to replace a piston and cyl because of a CAI mishap (hydrolock ) and replaced the oil in the engine with regular oil (I had run synthetic in it since 7500+ miles).

He said it should be fine, doesn't see anything wrong with it. No, I didn't ask for chemistry specifics... was just a question pertaining to the fixing of an old beater. Now there would be more involved questioning if it had been my Z or something...

 

As soon as I posted about not returning back to regular oil after use with synthetic I asked a guy at work if he knows why. Of course he answered "no". This is just something I have always heard as a STRONG recommendation.

My friend drives a '93 Maxima which he uses for long hauls and now has over 165,000 miles on it. At one point he did use synthetic oil, but changed back to normal a long time ago. And MyZ4u2c is completely correct in the fact that his engine did not blow up or anything. My best guess would have be that it might have something to do with regular oil beginning to "burn up" earlier on than does synthetic. When you change oil, you still have some old oil left in the engine so when you drive the car synthetic oil and regular oil don't mix (like water and oil). This would be my best guess so I wouldn't try to argue this. I am going to the dealership tomorrow and will ask the service rep. if he knows. If he gives me an answer I will post it a.s.a.p.

 

Just another source - The Car Talk guys answered this question on the radio couple of weekends ago I believe. No problem with switching back.

Again, not chemestry, but a fair amount of experience.

Then again, they thought putting bigger tires on a car would increase the gas mileage.

 

http://www.bobistheoilguy.com/

 

I asked the dealership service rep. today and he told me that mxing regular and synthetic oil is not a problem. There really is not a mixing problem. He did mention to me however if a vehicle has like 100,000 miles and has had regular oil all this time then not to switch to synthetic. He explained that synthetic "cleans" the engine and in an engine that old the only thing that might be stopping certain leaks would be the grime buildup from regular oil use. Once synthetic is inserted into the engine it will clean all that grime away and the engine has a high probability of attaining leak problems.

In conclusion he mentioned that some oils come mixed already like blends of synthetic and regular oil, so switching back and forth should not be a problem as long as the engine in relatively young. I will still use only synthetic oil starting with my next oil change at around 9,500 miles.

Please don't disregard that this is the opinion and personal experience of only one person. Others may have a different explanation and facts to back up another method of reasoning. If I come across someone that has the opposite opinion I will post their reasoning for the belief.

 

thanks for your help...... the dealer admitted to "not really being sure"..........it was found to have regular oil. Maybe once I find out more about it I will switch over to synthetic at 10-15k.

 

my beater is a 97 prelude (pure stock), bought new...put mobil 1 in after 50 miles. has always used a lot of oil (even when new) but with 135,000 miles it will still kiss 140mph...did the same with the z but waited a little longer (500mi), maybe seat the rings a little more. was being followed by my uncle in his ws6 me in the lude, my uncle was pissed; he said he had to blow the carbon off his valves to come around me (90 to 125)...don't think mobil hurt the lude early. did the same run with uncle in the z, he out ran me but backed off at 145...said the bird felt unstable, the z was rock solid, i would have out ran him on top end.

 

You can change to synthetic oil at anytime, do some research, synthetics are used from the factory in many cars. Also, modern engines are "broken in" after about 30 minutes.

JMS in TX

 

that seems like a pretty controversial statement about break-in.