oil change and reprogramming questions

Pretty accurate. 5,000 miles maximum. Fine if mostly freeway driving. Maybe a shorter interval if mostly city driving / short trips (4,000 miles I'd say, if you have a '97-'01 Camry... guys, what's your input?).

What year Camry do you have?

Maybe, but even if there is, you realize, fuel economy will suffer...?

If it's performance you want, there are plenty of V8 Cadillacs from the '80s to be had at a reasonable cost... they'll beat any rice rocket for sure. But you get only, what, 10 miles per gallon out of them.

Why not an ethanol-powered rocket? Ha ha ha

Michael

Because of the lack of precise information on exactly how long those sludge effected cars went between oil/filter changes, we have to err on the side of caution. I suspect 5000 miles or 8000 ks is probably safe,..but because its a simple exercise to change your own oil and filter, why not do it at a shorter interval and have the added satisfaction that your engine is going to last longer due to cleaner oil ? If you do decide to stick to 5000 miles intervals, monitor the oil condition. Provided it doesn't turn black, you should be safe. .

Also, I saw a show on the History channel about

There are some after-market software or in the case of later cars, reflashing of firmware facilities, which are supposed to improve engine performance. Personally, unless the ECU changes came with a bullet-proof garentee that they actually do improve performance *without* an increased risk of engine damage, they may be worth the $1000 or so,..but they would have to be *very* convincing, supplying dynomometer readouts etc and with verifyable engineering certification :-)

Jason

If you use a full synthetic, 5000 miles is no problem, and sludge is out of the question.

Is 100% synthetic oil capable of breaking down into sludge or in any other way? Or does it just get overloaded with carbon etc if you left it in for say, 30,000 miles. BTW, i worked at a petrol station as a second job for some years. One night the boss towed in a Holden (GM product in Australia) 6 cylinder which had no oil-pressure. Turned out the oil-pump drive shaft had sheared off. The old couple who owned it had never had the engine serviced in the 5 years they owned the car!! The oil came out as a thick gooey black syrup. Would have liked to see a mass-spectrometer analysis :-)

Jason

I cannot say for sure what would happen after 30,000 miles with synthetic oil. But believe it or not, it might not be in such bad shape if you had a really good oil filtration system.

The only time I challenged the dealership to answer on the sludging problem, they claimed that it occurs because the owners do not properly service the cars (oil changes)... In that series of Camry, the book said to change at

(Resolution of the class action recently ended up with Toyota having to accept responsibility, IIRC)

The other side of the story was that the PCV system was different on those cars......that the vacuum levels were lower and thus that the gases, water vapor, etc were not removed from the crankcase as efficiently as necessary. If this is the case, then synthetics would not likely fare any better than dino oils.

Ester synthetics are NOT inherently more stable than hydrocarbon oils under all conditions. Esters, when wet, warm, and catalyzed by either acids or alkali, can break down (hydrolyze).

And the last point in this discussion is that I have heard that the oil passages on some of these engines were rather small, making them more susceptible to blockages if there were problems with sludge.

The truth may be an admixture of some or all of these points.

Before you purchase a car the dealer/manufacturer want you to believe that a long oil change interval is needed (to look good against the competition). After you buy the car, they want you to think a short interval is required to reduce warranty claims and to increase service revenue. The truth probably lies somewhere in-between.

If you use a full synthetic at 7500 mile intervals (if your model year allows that), you will not have any sludge problems.

Perhaps you are right.....perhaps not.

I do not know, in the case of Toyota, but agree that the answer probably lies between the extremes.

The sludging issue is almost like a debate in Congress or like the "blind men and the elephant"...each has a view of the whole, but the whole is not necessarily totally revealed to anyone.

I certainly have no problems with synthetic oils, in particular. I had a new Passat a few years ago, and it "seeped" synthetic from day one and never stopped. Still, it was not intolerable.

If the warranty demands synthetics, then I use them. If not, I normally use a high quality petroleum oil and change frequently. I know all the arguments pro and con.

And maybe someday I will change my mind.. But not today.

Interesting about your experience with synthetic on a VW. Did you use synthetic very early in the life of the car (or was in factory fill), or did you wait until about 5000-10,000 miles before switching to synthetics? It is often recommended that you wait so the rings will seat properly with conventional oil (synthetic oil does not allow enough engine wear for the rings to seat properly). When Corvettes came factory fill with synthetics, they had this same problem.

It was a factory fill, Mark. This was a company car, so the vehicle was always serviced at the dealership in Europe. The EU rules are a lot stricter than what we see here and the seepage was put on official watch.

As an aside, the quality of mechanical work there was spectacular. When in for service and inspection, the car was taken into a workshop that was cleaner than most cafeterias in the USA. Service was by appointment, and technicians in white laboratory coats spent their entire time (not flatrating) testing and servicing the car. EVERYTHING was noted in an official report that followed the car.

And the law was such that if they didnt service or repair the car properly, they could be held legally responsible.

Clearly this level of service is not cheap but you get what you pay for.

I am completely sold on using synthetic oil for many reasons (including that it is cheaper than conventional oil in the long run), but the factory fill is a problem. It is really better to wait until at least 5000 miles before switching to synthetics.

The fact that factory fill synthetics have caused problems with failure of the rings to seat properly is a clear testament to the fact that synthetics are much better than conventional oil in preventing engine wear. Unfortunately, engines need a bit of wear in their first 5000 miles.

Maybe... I dont really know. When rebuilding an engine nowadays, the wear-in period is very short. Less than an hour, certainly. Now, I don't know what Toyota does to its factory engines.

I never had any problems with oil consumption in the Passat, so rings and compression were not an issue. Other than the troublesome little synthetic seepage, there were no issues.

I saw no particular benefit to the synthetic, but neither did it hurt anything. It was slightly more expensive than using dino oil, because I do not use long change intervals in any case.

When my new Avalon is delivered (about a week away), I will follow the manufacturers recommendation for oil quality and type, but will in no case go longer than about a 5,000 mile change interval. The cost of oil changes over the life of a car is inconsequential.

If you change your oil at 5000 miles, and that is the manufacturer recommendation, then you will save a little money up front with conventional oil compared to synthetic. But some people like to change at 3000 miles, and switching to synthetic at 5000 mile intervals instead will be better for your engine at about the same cost.

The long term cost savings of using a synthetic could be substantial in some cases , but it depends on a number of factors, including how long you keep the car. If you try to sell the car yourself, and you have documented oil changes using synthetic oil, I would bet that you can get at least $500 more for the car than otherwise.

conventional

I keep a logbook. We normally keep a car a fairly long time. The Buick we are replacing is some

I really doubt that the use of synthetic will have a big impact on resale value, but this is total speculation.. Would like to hear the opinions of others on this subject.