The real deal regarding synthetic oil change intervals

Dear Car Talk:

When I bought my 2011 Toyota Camry, the dealer told me that the synthetic oil didn’t need to be changed so often, say only about every 10,000 miles or so. Since I had free service at the dealer initially, I took it there for regular maintenance, and despite what they told me, they kept changing the oil and filter much more frequently than they said was required. I didn’t care, since I wasn’t paying for it. Once my free service visits ran out, I started taking it back to my regular mechanic, who changed the synthetic oil every three months. Since the synthetic oil is more expensive, when my husband asked about this, one of the other guys at the shop (not the head mechanic) told him, “The dealer just wants you to ruin your engine and buy another car!” The head mechanic suggested I could go 5,000-6,000 miles between oil changes, depending on the type of driving. Yet the reminder sticker they put on my windshield is again for 3,000 miles. I pointed out that the mechanic might want us to pay extra, more often, for the more expensive oil changes that aren’t necessary. What’s the real deal with synthetic oil? – Susanne

RAY: The dealer is right. Unless you drive the car extraordinarily hard – like using it as a taxi in Phoenix in the summer – synthetic oil is designed to go about 10,000 miles between changes. Changing synthetic oil every 3,000 miles is far too often.

As mechanics, it takes us a while to catch up with reality. Oil changes used to take place every 1,000 miles. And it took years before mechanics accepted that 3,000 miles between changes was OK. So there’s a lag in acceptance among mechanics that synthetic oils are really far superior to conventional oils.

If you want to be extra safe and err on the side of caution, I’d say you can change your synthetic oil every 7,500 miles, which is the typical service interval for lots of cars anyway. But I wouldn’t hesitate to recommend that most of my customers go 10,000 miles. While changing it any more frequently than 7,500 won’t harm anything – except your bank account – it’s really not necessary.

So buy a bottle of Wite-Out, Susanne, and keep it in your glove box. And then every time you drive away from an oil change, just change the mileage on the reminder sticker.

How to evaluate a used car

Dear Car Talk:

I am trying to buy my first car. I decided to save up and pay cash for it. I found a possible car here in town. It is a 2004 Lexus IS 300 with 64,000 miles. What are your thoughts on it? I went to test-drive it, and it drove well. The only major repairs that I could see in the future would be a new key fob, tires, brakes and some hail and paint repair. – Rafael

RAY: It’s a nice car, Rafael. In general, Lexus makes good cars. And – in general – a Lexus with only 64,000 miles on it should have quite a bit of life left.

However, you don’t buy a used car in general – you buy a specific used car. And you don’t know whether it was driven by a little old lady to Gamblers Anonymous on Sundays, or by her 21-year-old grandson, who took it racing three times a week.

So, how do you evaluate a used car? You have a mechanic do it for you.

Sure, if you test-drive a used car and it squeaks and rattles and thumps and smokes down the road, and smells like Edward R. Murrow’s ashtray, you can determine it’s not the car for you and move on. But if you drive a car for 15 minutes and it “drives well,” there still could be lots of hidden problems.

And you need to be careful right now, because you’ve probably already fallen in love with this car. You haven’t given it a name yet, have you?

If you’re seriously interested in the car, take it to a mechanic you choose and trust. If you need help finding one, do a search at You’ll have to pay the mechanic for an hour or two of labor, but it’s well worth it.

Ask him to check everything. Have him check the compression, pressure-test the cooling system, look for leaks, check the brakes, the exhaust system, the steering components, the tires, the suspension and anything else he can think of that’s expensive.

Ask him to tell you everything he finds wrong with the car – which of those items are urgent, which can wait, and what the costs are for each repair. Then once you have the whole story, you can decide whether you still want to buy the car. Or you can decide if you want to buy it, but at a lower price because of the repairs it needs. And you can use that list of repairs to negotiate a fairer price with the seller.

By the way, buying a car with cosmetic damage, like hail and paint damage, is a great way to save money on your first car. Not only does it decrease the value of the car, but it’s also the kind of repair that can wait indefinitely, or at least until after you bang it up a few more times while you’re learning to drive – which most new drivers do.

But get it to a mechanic first, and make sure the transmission isn’t full of overripe bananas before you fork over your hard-earned savings, Rafael.

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