I was checing out the owners manual of my sister´s car, and it said very specifically that the oil now should not be changed as often as with other older models, but rather every 18000 Kms. (A little over 11 tousand miles, which is almost 4 times the ammount of miles allowed on older cars). The car performs really well. Now, is it because of the engine or because of the quality of the oil? It is just a European thing, or the newer cars n America have the same thing? Just curious to know!

You didn't say what car your Sister has. I'm assuming You have the 1997 RAV and wouldn't be asking that question 10 years later. I'm not an "expert" but I've heard from dealerships and other mechaniacs that the newer car these days can go way much longer than the 3k miles before an oil change. Newer/redesigned engines make this happen. IF this is what the manual says to do , then that's what I would do. The last vehicle I owned was a 2000 Dodge and up till then I was ALWAYS changing my oil every 3k miles. My 07 YARIS can go 5k before an oil change (according to my manual and dealership). I'm just wondering though, I just put synthetic in and do I have to change it again at the next 5k or can I go longer????

sambo42xa
New Hampshire
USA

Hi Sambo! I just left you a question in your introduction about the change of oil. Thanks for answering. My sister has a Citroen Xara Picasso, I think the year is 2003. I already talked a lot about it in the "Other cars" section, because I am on vacation and staying with her, finding out about that car... Thanks!
And yes, I had a RAV4 1997... but not anymore since I moved to Germany. because I sold it (still sad about it! I loved that car more than my first husband!)
Anyway, welcome to the board!

I never really had engine trouble. But I drive mainly 4 cyl. vehicles, and use 20w50 at least 10 months a year, and I am not really interested in anything that I cannot get at least a 1/2 million miles on. When I get a 100k on something, I add the first three numbers off the odometer together. If I have 1-5-6, then I get 12 and it is divisible evenly by 3, then my oil needs changed. That way I am always between 3 and 4,000 miles. Oil is cheap, and I buy Toyota filters by the case, and together that is cheap engine insurance.

Oil changes are cheap enough to either do yourself or have done so I'm a stickley about doing it
at least everything 4000 miles. Can't hurt!

I have also heard every 6 months if you don't go over the mileage limit...but I really never followed that rule.

Not to jump off topic, but the oil never breaks down. The detergents wear out though. Technically your oil would be good for a long long long time. I havent changed the oil in my explorer in 20,000 miles now. I have only added 2 quarts since then. I only do this cause its at 242,000 miles though and I dont really care about it. But I would go with what the manual says, and keep receipts to prove the work was done.

Wow ...20K and no change. Don't you wonder what that oil looks like? Kinda gunky?

Na, I dont really care that much. But in my camaro, I change the oil every 3-5k. If it makes it that long without me pulling the motor.

I'm just wondering though, I just put synthetic in and do I have to change it again at the next 5k or can I go longer????


I think all newer Toyotas are going 5K miles btw oil changes. It all depends on how you drive, alot of stop and go, will require more frequent oil changes. They recommend not running synthetic oil in the car till after your breakin period to let the gaskets seat properly(go figure). And unless your car's a Porsche, Ferrari, Corvette or some other high performance car it doesn't need synthetic at all. Just tryin to help some peeps save a dollar. (IMG:style_emoticons/default/460.gif)

The oil itself deosn't wear down but it gets contaminated with all the metal shavings inside the motor. The oil serves several purposes, one to lubricate the motor, two to cool the motor and three to suspend and capture against FOD(foreign object damage). (IMG:style_emoticons/default/beer.gif)

The only way to find out if your oil can go longer between oil changes is to do an oil analysis.

http://blackstone-labs.com/

That's a cool site ...especially for those of us who are curious about every damned thing (IMG:style_emoticons/default/grin.gif)

Ive always wanted to do one of those tests, maybe on my old oil from my exploder. I think that would be a funny sample to send in.

Yes, I would like to see the results from that sample. They may ask for more samples from you (IMG:style_emoticons/default/clap.gif)

Even with my older car, I always stayed close to 5000 miles. I really wouldn't feel comfortable going to 11000, even with a new car, but if the manual says to.... I would just suggest checking the oil yourself ever so often to make sure it doesn't need to be changed more often.

I change mine every 3,000 miles. Im not a believer in extended drain intervals. No matter how good the oil or filter is, oil still gets dirty and you need to change the oil often to drain the dirt out of your engine.

Synthetic lubricants make wear and tear on gears far less than on the petroleum based lubricants, reduced the incidence of oil oxidation and sludge formation, and allows for extended drain intervals. Today, synthetic lubricants are used to lubricate nearly all lubricated components often with superior performance and longevity as compared to non-synthetic alternatives.

Instead of making motor oil with the conventional petroleum base, "true" synthetic oil base stocks are artificially synthesized. ("Commercial" synthetic oils are in fact Group III mineral base oils.) True synthetics include classes of lubricants like synthetic esters and polyalpha-olefins. Higher purity and therefore better property control means Synthetic oil has good mechanical properties at extremes of high and low temperatures. The molecules could be made large enough and "softer" to retain good viscosity at higher temperatures, yet branched molecular structures interfere with solidification and therefore allows flow at lower temperatures. Thus, although the viscosity still decreases as temperature increases, synthetic motor oils have a much improved viscosity index over the traditional petroleum base. Their specially designed properties allow a wider temperature range at higher and lower temperatures and often include a lower pour point. Because the viscosity changes much less with temperature, synthetic oils need little or no viscosity index improvers that are used with the traditional petroleum based oils. The viscosity index improvers are the oil components most vulnerable to thermal and mechanical degradation as the oil ages and wears out. Because synthetic oils have little or no viscosity improver content, they do not degrade as quickly as traditional motor oils. However, they still fill up with particulate matter like the conventional oils do, so the oil filter still fills and clogs up with time and must still be changed periodically. Synthetic oil should still be changed periodically because the particulate matter builds up at the same rate as in regular oil; but some synthetic oil suppliers suggest the intervals between oil changes can be longer, sometimes as long as 10,000 - 15,000 miles between oil changes.

Some tests have shown that true synthetic oil is superior to conventional oil in many respects, providing better engine protection, performance, and better flow in cold starts than petroleum-based motor oil.

Interestingly enough, a test by Consumer Reports showed that taxi-cabs exhibited the same amount of engine wear regardless of which oil was used.

Personally, I use a full synthetic because:
a. time between changes is longer
b. i live in a +30 to -40 degree climate and i get superior starting

Somebody called SS..something said that oil doesn't breakdown. The additives go first, and they yes, the oil breaks down. Many synthetic motor oils are rated as if they were a multi-grade motor oil containing a polymer-additive because they have the broad temperature range of polymer-enhanced oils but those polymers are not actually present. Thermal breakdown of the polymer-enhanced products can occur at high temperatures and can contribute to carbon build-up.

I do apologize for the length of this post folks. I don't get to the