Synthetic OIl

The statement from Toyota Customer Service about not switching from synthetic to conventional oil is not new. It has always been there.

I do not know the reason for the recommendation.

Doesn't make any sense. It may have been good advice when synthetic oil first was used for street use in the early 70's but, in 2005? Come on!

My dad is a chemist, who helps make some of the synthetics (he is in his mid

Many moons ago someone who wrote drivers manuals for Toyota wrote that clause in just to be safe. Ever since then the younger generation of manual writers have come across this and thought that it was probably put in for a reason, although they had no idea why, and thought it probably safer to leave the advice intact just in case there was a good reason for it. Strange but possibly near the truth. Of course it could just be that once a high priced oil has been used then the benefit [if any] would be partly squandered if the engine was subsequently relegated to using dyno. Who knows?

Huw

While it probably doesn't matter if you put in natural oil, your Toyota dealer should put in the oil you specify. Mind does. My dealer recommends if you want something other than what they use (Havoline, in the case of my dealer) that you bring in a jug of the oil you want, as that will be cheaper than paying the dealer for the oil.

For example, I use Mobil 1, which I buy at Walmart for about $4 a quart ($20 for a five-quart jug). The dealer would charge me $7 a quart to put in Mobil 1, if they provided the oil.

Merritt

Is Wal-Mart a good place to get oil changes? I used to get my Tercel changed there before the Wyman'ing.

Now that I'm going to buy a Camry, though, I would like to be sure Wal-Mart gets the okay sign.

I would suspect that just about all dealers stock synthetic oil and will use that if you pay extra for the oil change.

I don't have an answer to your question, but I wonder if it has anything to do with the seals and how they would react to different formulations or chemicals between the oils. This is just a guess.

Changing the oil is not rocket science. If they put a good quality oil and a good oil filter and put the drain nut back on tight, it doesn't make a difference where you have it done, IMHO, of course. If they put some kind of house brand oil and filter, I'd run to a good garage instead.

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Although it was the case in early 70's, synthetic oils contain seal swelling additives.

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As far as I know, it shouldn't be a concern since synthetics and dino are compatible.