Oil has been talked to death, but I couldn't find anything to help me with this particular question.

I've been taking my G37 to the dealer to get the oil changed regularly and I have no idea what they put in it. I know it is 5w30, but I don't know if it is synthetic or not. They once told me it was conventional Mobil, but I thought Mobil only made synthetic... so who knows. Then the whole Ester oil fiasco happened and they put Ester oil in once or twice (free of charge because it was related to the TSB).

Well now I want to start taking my own oil to the dealer to save money until I move somewhere where I can change it myself. Costco has Mobil 1 5w30 synthetic on sale right now so I'm thinking about having that put in... but my question is... does switching around from whatever the dealer used (possibly synthetic?) to Ester to synthetic again cause any problems?

Please don't turn this into a thread about which type of oil is better - I just want to know if switching to/from ester <-> synthetic <-> conventional and/or back will hurt anything.

 

The "ester" oil at the dealership is nothing more than conventional 5w30 with an ester additive package (which synthetics also have certain types of esters). So in a short answer, no...it will not hurt your engine to make the move to synthetic (and Mobil 1 synthetic is just highly refined/purified "dino" oil (conventional 5w30)).

But you SHOULD try to pick an oil and stick with it. I'm doing the same thing and bringing my own oil to the dealership at my next service and will probably do so from now on, unless I start doing the service myself.

 

You can switch types and brands as often as you please. All oils are fully compatible.

 

Thanks guys! *whew* I was a little nervous about what to do now not knowing what they had put in previously...

 

That is the complete opposite from what I've always heard when working at various vehicle service shops with seasoned mechanics. You should not switch brands and/or type back and forth because different brands use different detergents which CAN have little chemical reactions inside your engine, reducing the life of the engine. Granted, you may never see the result of it. You might get rid of the car before something happens related to that, but you SHOULD stick to the same brand/type oil. I've always been told by mechanics that have been in the business for a long azz time that it's also not good to go from synthetic blend to conventional, synthetic to synthetic blend, or synthetic to conventional either. You should never go down, only up.

Let the arguments begin

 

Your seasoned mechanics should stick to turning wrenches. Part of API oil specs since the beginning of time is that all oils have to be fully compatible. You are not going to have any reaction in your engine. You do realize that synthetic blend oil is just that - synthetic and conventional oil mixed together in the bottle on the shelf. How do you suppose such a product could be sold? Not only can you switch at each change, but you can GASP mix oil together. You could even mix 5 different quarts together at your next oil change with no ill effects.

There is just a bottomless pit of oil misinformation and OWT.

 

Well have fun mixing your 5 different brands together. I'll stick to one and we'll see who's engine has the longest life.