Synthetic for old Celica?

You should be fine with synthetic. The leaking problems went away as the oil makers changed their formulas.

jeff

How long do you want to lengthen the oil change interval?

The synthetic should not cause leaks.

IMO, it is possible that synthetic oil could allow more oil to slip past the rings if you previously used conventional oil and your car has a lot of miles on it (with the associated engine wear).You might want to use at least a 10W-40 synthetic to lesson the chances of this happening.

But there is also now a Mobil 1 High Mileage 10W-40 oil that you may want to consider since it contains a special seal conditioner to help recondition seals and prevent leaks. The slighter higher than normal weight will also minimize the oil from slipping past the rings.

I think you could go up to 10,000 miles with Mobil 1 if you use a very good oil filter. But I would do my first change at 3000 miles after initially switching to a full synthetic, since it might loosen up some existing sludge in your engine (unless you are certain it is clean as a whistle).

Ha-ha. Whatever ppl say + manufacturer's recommend then take the longest of all suggestions. That was my plan anyways. :)

There are people who post in this group who know little about cars, lubricants, and automotive lubrication systems. If you want the engine to last, follow the automaker's oil change interval recommendations.

Since you do not work for a company that makes synthetic motor oils, and as I recall you don't use a full synthetic in your own cars (and generally think it is a waste of money), I don't think you are in a position to comment on the knowledge of others on the subject of oil change intervals for synthetic oils.

It is certainly not correct that an oil change interval would be the same for a conventional and full synthetic oil. The only possible exception "might" be the oil filter, but if one uses a high quality filter (I typically use a Mobil 1 filter) and don't go crazy, one can go a bit beyond the manufacturer's recommendations for oil change interval (which are generally designed for conventional oils). Obviously, one would not recommend this while the car is still under warranty for purely contractual reasons.

I am convinced (after much study of this subject) that anyone who drives more than 3000 miles on conventional oil (even if the manufacturer specifies

5000 mile intervals) is subjecting their engine to much more abuse than they would by using a full synthetic with 10,000 mile oil change intervals (if they use a high quality filter).

No my experience is not with an oil company; it is with the automaker. Do you have work experience with an oil company or automaker?

I do use synthetic in our three personal vehicles, but not because it saves money. I use it because I prefer to use quality parts and materials in my vehicles and follow the automaker's recommended oil change intervals, which for our vehicles is 5,000 miles.

I am a little leery of "studies" by the oil companies, which have something to gain by showing an advantage from using their product. I would believe a long-term study of vehicles in a controlled and consumer use environments by an independent testing agency, automaker, or API but have yet to see one. The studies I have seen from sources that I consider credible without a hidden agenda do show performance and wear benefits from using synthetic oil, and that is why I use synthetic oil. From a cost standpoint, even at double the oil change interval, the math doesn't seem to work out with synthetic oil at triple the cost of conventional motor oil. Bottom line, I use synthetic oil because it is good stuff, not because it saves money.

No. But I do have experience working for NASA, although that does not make me a rocket scientist. Likewise, your experience working for an automaker was not as an automotive engineer.

The automaker you worked for does not recommend synthetic oils (although I don't think they recommend against it). A person who is knowledgable about motor oils could reasonably conclude that if the automaker specifies conventional oil, then their oil change interval is for conventional oil, and not for synthetic oil (it is not practical for them to differentiate, becasue it would be almost impossible for the automaker to know for sure what the customer used). Likewise, if one was using synthetic oil, one could theorectically go a bit longer between oil changes. Most auto makers in Europe have much longer oil change intevals than in the US, even for the exact same cars as sold in the US.

That is strange (to put it mildly) since I don't recall you ever recommending synthetic oil. Is this a fairly recent turn of events?

I never said the study was by an oil company. I don't even see how it is in the best interests of an oil company to advocate prolonging oil changes. The other thing to remember is that the vehicle in question has 300,000 miles on it, all with conventional oil (I am presuming from the OP). If someone really, really wants to extend there oil change interval on a car with

300,000 miles, and they are using a full synthetic, I don't think 10,000 miles is unreasonable. I would not use a 10,000 mile interval on a newer car, but that is just my opinion.

True, which is why I got information from the automotive engineers that designed the cars and engines.

I've been using synthetic oil for about two years. Although I use it for the reasons I stated, I don't actually recommend it because all those years of working with engineers has made me think like them. The recommendations I make in this group are very conservative. If I don't have personal knowledge or experience about a subject, I either do not make any recommendation or preface the recommendation with "in my opinion" or "I think." The customers who came to me for advice or information were looking for expert advice, and expect that advice or information to be correct and with a basis of knowledge far above what they get from their friends, relatives, neighbors, auto service chain, auto magazines, and even their dealers. In order to meet those expectations, I very quickly learned to differentiate what I *know* and what I *think* and if I didn't know, to go to the people in the organization who did know for information.

I don't doubt that synthetic oil provides ample lubrication well beyond the

5,000 mile mark, but besides providing lubrication, motor oil has to suspend the by-products of combustion, some of which are not captured by the oil filter. Those by-products are what make motor oil turn black over time. I change the oil in my vehicles myself, and the used synthetic oil coming out is just as black as with conventional oil, and I'm not convinced that it is a good idea to keep circulating the dirty oil through out the engine and oil filter. For example, if you were comparing two different dishwashing detergents in two sinkfuls of water, and detergent A could wash 50 dishes and detergent B could wash 100 dishes effectively, that would mean that the water in the sink with detergent B would be twice as dirty, even if you were filtering out all of the solid particles in the water. In the case of whatever is turning the oil black, perhaps it doesn't do any harm to have twice as much of it in the oil, but I personally do not *know* whether that is true or not so I take the safe route and stick to the factory recommendations for oil change intervals.

I doubt that you talk to them directly, since the engines are designed in Japan, even if they are made in USA. But anyway, I get my information from the same people, but not necessarily just from Toyota engineers. Also, I get the "unofficial" and "off-the-record" opinion, and not the company policy.

This is not a very convincing reason for you to use synthetic in your own personal vehicles, but recommending conventional oil for everyone else. The obvious reason for your behavior is that Toyota does not specify synthetic, and you are toeing the company line rather than giving good advice.

Toyota does not want to specify synthetic because that will be competitors an advantage (the Honda sales person will tell you how much more money you will have to pay for synthetic oil changes).

Such hyperbole may be appropriate for a brand new vehicle, but is rather ridiculous for a vehicle with 300,000 miles on it.

Since I no longer work for the company, I no longer talk to them directly. When I did work for the company, the Japanese engineers often came to our office when they wanted to visit dealers to check out customer cars because I was one of the few people in a field office that could speak Japanese. When Toyota's engineers want to study real world perfomance of the vehicles they designed, they contact district service managers and ask them to contact their dealers and ask them to bring their vehicles to the dealership on the days that they are visiting in return for a free maintenance check It was a lot easier for them to just call me and explain what they wanted in their native language than to have their request translated and then arrive at the dealership and find that someting was lost in translation.

Yes, I'll admit that the information I provide does reflect Toyota's company policy. ;-)

When people are looking for technical advice, I suspect that they often want the automaker's company policy or opinion, more than unofficial and off the record opinions.

I think you are confusing my recommendations, probably because they are not always clear, and perhaps because you think that the only reason to use synthetic oil is to extend the oil change intervals. I am not saying that everyone should use conventional oil. I am saying that if one uses synthetic oil, one should still stick to the automaker's recommended oil change intervals.

I think we'll have to respectfully agree to disagree. I guess people looking for advice can decide for themselves whether your advice, which is based on your research from various sources, watcing the guy at the quick change place change your oil from start to finish, and unofficial and off the record opinion, is good or better advice than mine, which is admittedly based on Toyota's company line and the engineers who designed the engines and who don't want Honda to have an advantage over Toyota in oil change recommendations.

Why is it ridiculous? What is the difference in needing engine protection between a brand new vehicle and one with 300,000 miles?

Maybe you should re-read the OP. He has a "old Celica" with 300,000 miles. I think it is rather insulting to suggest he cannot read the owners manual with regard to oil change intervals. He wanted some "out of the box" advice for his particular situation.

IMO, especially on this forum, we welcome "unofficial" and "off the record" opinions form informed sources. At the very least, you should have disclosed a long time ago that you were using synthetic oil in your own vehicles, while recommending conventional oil to everyone else.

No, I have posted at least a hundred time on the subject of synthetic oil that there are many other benefits besides extended oil change intervals. Since most cars are still under warranty, it is usually a moot point anyway.

However, I have also said (many times) that if one is using conventional oil, they should be changing every 3000 miles, so perhaps if one goes 5,000 miles with synthetic that is an extended oil changed interval. Synthetic oil protection of engine parts is vastly superior at 5000 miles (or even 7500 miles) than conventional oil is at 3000 miles. In any case, one should always comply with the manufacturer recommended oil change interval (which for my Toyota is 7500 miles) for a car under any kind of warranty.

Well we agree on that. The rest of what you said is a complete distortion of my background and what I said on this subject.

An "old Celica" with 300,000 miles using conventional oil (I presume from OP) is out of warranty and has already had lots of engine wear, unlike a new car. Another factor is the value of the car and how much time and trouble one wants to put into it before it is scraped. I find your inability to comprehend the difference a bit shocking.

Anyway, if one goes 7500 miles on conventional oil (the Toyota factory recommendation for an "old Celica"), then 10,000 miles on Mobil 1 (with a high quality filter) is not out of line for a an "old Celica" with 300,000 miles on it.

Yes, perhaps I should have disclosed that I use synthetic oil.

You keep coming back, reinforcing your perception that I was recommending conventional oil. I do not recommend conventional or, for that matter, synthetic oil. My recommendation is that one does not extend the oil change intervals beyond the automaker's recommendations, regardless of the oil used.

You should note that I have not refuted any of your posts regarding the benefits of synthetic oil besides the benefits of extended oil change intervals. The only part that I disagree with you on is that extending the oil change intervals is a benefit, and perhaps I misunderstood your interpretation of "extended."

I guess we had a difference in interpretation of what constitutes an "extended" oil change interval. My interpretation seems to be narrower, since I had considered anything beyond the factory's recommendation, as opposed to whatever interval people were using, to be "extended."

Synthetic oil

My distortion is unintentional. I thought you said in previous posts that you have done research on the subject of syntheitic oil from various sources and that you take your car to quick lube places because they allow you to watch your oil being changed, while the dealers near you do not. I apologize if I left other relevant automotive experience or background out. I merely meant to summarize the OP's choices for sources of information and opinions.

An old engine with lots of engine wear will produce more blowby gases and therefore place more contaminants in the oil in a given mileage interval than an engine with less wear. While a good oil filter can remove the particulates, there are more particulates to remove in an older engine so the oil filter will theoretically reach its limit sooner, and so extending oil changes intervals seems to me to defy logic. I think synthetic oil will certainly help in an older engine, especially if it is not so worn that it is using oil and wasting the more expensive oil.

Another factor is the value of the car and how much time and trouble

I find your inability to

We obviously have different viewpoints on the matter, and you seem to take a difference in opinion or a correction or clarification of facts as a personal attack and respond with personal insults.

As I've said before, I think we should respectfully agree to disagree ;-)

Personal insults? I just said your inability to differentiate between an "old Celica" with 300,000 miles and the requirements of most other people who ask questions on this newsgroup is "shocking" and "ridiculous." I don't regard those as personal insults. I was criticizing your posts, not you personally.

However, now I will make a personal insult. I strongly disagree with your self-described "neutral" characterization of all your previous posts about synthetic vs. conventional oil. You should have disclosed that you use synthetic oil in your personal vehicles. That was a very serious lapse of judgment on your part, IMO.

Apparently we don't disagree about the benefits of synthetic oil (since we both use it instead of conventional oil). What we do disagree about is what kind of advice one should give on this newsgroup, and we apparently disagree about requirements of "full disclosure" so that readers can make their own informed decisions based on all the facts.

Of all the people on this NG, you go after the most competent and helpful poster?

How Dare You?

What the hell are you talking about?

You are making an arse out of yourself.....

"Mark A" wrote in message news:k9Krj.81119$ snipped-for-privacy@bignews5.bellsouth.net...

As I've admitted before, and I'll admit again, in hindsight, I should have disclosed that I use synthetic oil in my personal vehicles. At the time, I didn't even think about what type of oil I use because I considered it to be anecdotal and not relevant, and nobody asked. My mindset was still in "factory rep" mode, where I thought about the hundreds of thousands of Toyotas operating in our region rather than my limited experience with my personal vehicles. In hindsight, it would have appeared more neutral if I had disclosed that I use synthetic oil.

Fair enough! If someone wants the factory's advice or point of view, I'll provide it, and if someone wants "out of the box" advice, you can provide it!

I don't think the advice and information I provide is wrong, inaccurate, or not credible very often, at least I hope it isn't! Perhaps the people I've provided bad automotive advice to can pipe in so I can have an opportunity to correct that advice, and in the interest of full disclosure, the people I've provided good advice to can also share so I know if I'm on the right track. I didn't think anyone cared about what Ray O uses in his personal vehicles, but if anyone thinks that what I use is relevant to a discussion, ask away!

BTW, I use Castrol Syntec 5W-30 and Toyota OEM oil filters in our '97 Avalon with 130,000 miles, '03 Sequoia with 60,000 miles, and '01 LS 430 with

80,000 miles, changed at 5,000 miles intervals. I change the oil myself, and a friend brings my old oil to the dealership where he works for disposal. I use conventional straight 30 weight in the lawnmower and snowblower and change the oil once a season. I pretty much use only OEM parts because I know their quality, and the local Toyota dealer is open until midnight on weekdays so it is very convenient for me. I use aftermarket windshield wiper blades and refills (Exact Fit) because they have been "good enough," and the other aftermarket parts I can think of that I use are Weathertech floor mats, which last longer than the OEM Toyota mats I ordered for the Sequoia, where the seam split in front of the accelerator pedal from the driver's heel. Coolant is Toyota red in our vehicles and I have some Peak or Prestone in the garage for taking care of the people without Toyotas who ask me to look at their cars. Windshield washer fluid is the cheapest stuff I can find on sale to buy a case of in the spring. Tires are a mixed bag - whatever has the highest tread wear rating on display in whatever store I happen to shop for tires at in a brand I've heard of that isn't Firestone. I generally prefer Die-Hard batteries from Sears or Interstate from the local Toyota dealer, although I had a cheap no-name brand installed in the Avalon this month when it was below zero, my son had to get to class, and the local gas station was fast. I paid $97 for 1 hour labor to the gas station, which is about the same as the Toyota dealer. If I didn't have an appointment with a client, I would have swapped the battery out myself, saved the labor charge, and got a better battery.

I am talking about the fact that in all the posts he made about synthetic vs. conventional oil, he never once disclosed that he uses synthetic oil in his 3 personal vehicles. This is a fact that once would not have surmised by the content of his previous posts on this subject.

Whooosh. The sound of reality going right over Scotty's empty head.