The Dealer says

When I bought a new 2010 Highlander Toyota in December 2009 the dealer said to always use Synthetic oil . My sister bought an identical Highlander same engine etc., in May 2011 wih 15000 miles on it and the dealer told her it was okay to use regular oil.?? What gives?

What gives is that the only legitimate source of information is the vehicle’s manufacturer, not the people at the dealership.

Fortunately, the manufacturer has provided the correct information regarding the oil specification–as well as everything else regarding the vehicle’s operation–in the Owner’s Manual.

Open the glove compartment, take out the manual, and read what the folks who designed and built the engine have to say on this topic. Disregard what you are told by the people at the dealership–on this topic, as well as anything else that they tell you–unless you can verify it via the manual.

As VDCdriver said, follow the instructions in the owner’s manual. It would be a good idea to read the whole thing. Lots of important and useful information.

Further proof that auto salesmen don’t know as much about their products as do many of their customers.

The only people at the dealership who actually know anything about the cars they sell are the ones you will probably never get to speak to: the technicians in the service department. Please note that technicians should not be confused with service writers, service advisers, or service managers, as these people are often little more than salesmen and often know little to nothing about auto repair, maintenance, or the cars the dealership sells. They often only know how to get people to buy filters and fluid exchanges and anything else that will get a customer to empty their wallet.

But seriously, read your owner’s manual. Even just spending 15 minutes reading it will tell you more about your car than you ever thought you would need to know, including what type of oil to use, when your fluids need to be changed, what all those weird looking symbols on your instrument panel means, how to get your defroster to work best, and lots more. Use it as bathroom reading if you have to. A couple sessions with your owner’s manual on the porcelain throne will educate you very well.

This is another vote for reading your owners manual. In over 40 years of driving I have never had an owners manual lie or mislead me about anything. The little manual was always there for me and is full of useful information. It can be your best friend when it comes to questions about your vehicle. It always speaks the truth.

The ONLY authority is the OWNERS MANUAL.

It’s in the glove box. I suggest you read it. It’ll spell out EXACTLY what to use and how often it should be changed.

I agree with " mark" on all of his points ESP. about best bathroom reading material. ;=) If one of the dealers differ from the recommendations made in the owners manual, it’s probably more profit motivated then stupidity…assuming that both will be dealer serviced. The sales pitch continues well after the sale.

As to the longevity of your engine I don’t think the type (dino or synthetic) will make one iota of difference.
The big issue is changing what’s in there regularly enough based on driving habits, environmental conditions, state of tune, and so on.

The downside to synthetics is that it promotes the ill-advised idea that using synthetic oil means you can go 10k miles between changes, that it stays cleaner, oil consumption is nil so one never has to raise the hood to check the oil level, and so on. This leads to the common, “my engine is trashed/sludged/fill in the blank and I’ve always used synthetic…” complaint.

Keep in mind that when you say “the dealer says” what you mean is that a service writer or service manager says. What those mechanically inept people say is often at odds with what a mechanic may say.

I do disagree that the owners manual is always the a final authoritative source for what’s correct. If that’s the case then bad recommendations about not having to change the trans fluid, checking valve lash, lifetime fuel filters, and so on would not be printed.
Probably the most embarassingly bad recommendation I’ve seen is the one about valve lash checks and how it should be performed. If the engineers are behind this then they need to go back to school; if it’s the marketing department then it’s undestandable.

I had an owners manual lead me astray once. I bought a new 81 Horizon with a 2.2 engine and went merrily along for about 50,000 miles changing my oil and filter with the specified products. It turned out the Chrysler was having trouble with cam wear on this engine so they changed to a very small oil filter so the cam would get oiled sooner at startup. When my valve train became noisy I took the oil filler cap off and could see scoring on a cam lobe. I went to the dealer to get a new cam and found out about the change in filters, but the dealership told me there was a goodwill offer that they would replace the cam for $75 (much less than buying the cam) so I was happy.

Trust your owner’s manual. The guy at the dealership could have been telling the truth (if so the owners’ manual will agree) or he COULD have been telling you this so they’d rake in more money for oil changes. It’s possible that he even believes it…there are many people that believe that synthetic is superior, even where it’s not needed.

The real question is “what is required to keep my warranty in force?”

Surprised no one’s mentioned that.