slt

iTrader: (2)

Study
This study is still ongoing, but they have already had some intesting findings. Their Mobil 1 study showed the oil lasting 18,000 miles before it needed to be replaced. Even more interesting to me is that they found that engine wear actually decreases as an oil ages a bit. That is to say that your engine actually wears more if you change the oil too frequently. They seem to be finding that 5-10k mile change intervals are more appropriate.

iodine23

iTrader: (1)

Wow, good find! I wonder if you can assume other engines will follow similar trends. I don't see why not.

CLeeEvo

The test vehicle is a 2002 Chevrolet Camaro Z28. It is a naturally aspirated engine and not a high-boost turbo car like an Evo. I would think that has a significant impact on the oil analysis.

jwtodd60

While I was poking around that site, I ran across a link to an oil filter study I had not seen before. Fairly in depth, but a little bit out of date (not too bad though, last update was 2002). Enjoy...

http://www.shoclub.com/lubrication-o...n-oilpart1.htm

JW

krzyray

How can changing your oil too frequently be bad for your engine?! This doesn't make sense. Somebody please explain! Thanks

slt

iTrader: (2)

Here is a quote from the study;

"Engine wear actually decreases as oil ages. This has also been substantiated in testing conducted by Ford Motor Co. and ConocoPhillips, and reported in SAE Technical Paper 2003-01-3119. What this means is that compulsive oil changers are actually causing more engine wear than the people who let their engine's oil get some age on it.

Based on the results we've got here, we'd recommend 8,000 miles between oil changes on an engine that uses no oil at all, perhaps 10,000 miles on an engine that uses some oil, and 15,000 miles or beyond with a filter change every 5,000 miles. This, of course, isn't any kind of guarantee, and you must evaluate for yourself what your engine requires. One thing we're pretty sure about though: 3,000-mile intervals is a huge waste of resources"

WINSTON

iTrader: (6)

On newer Porsches (97 & up) the factory recommends the oil should be replaced every 15,000 miles or one year which ever comes first. This is with the factory recommended Mobil One motor oil.

Here in Arizona we recommend to our customers (Porsche cars) to change the oil at 7,500 miles because of the high heat and dust issue.

Winston

camino cielo

I have always believed that when you change the oil and you first start up the car you dont have much pressure (or oil in various orifices), I always used to cringe when i see the oilpressure light be on for a few seconds which seemed like an eternity, hence, the extra wear on engine. I used to pour some oil into the filter to facilitate the circulating of oil the first few seconds, of course this was difficult with cars having filters sitting horizontal.
So this would be an answer to krzray.

iwantaskyline

europe has been doing 15k oil change intervals for years.

Creamo3

iTrader: (48)

This info. is interesting indeed, it must be the oil companies that are recommending such low mileage to change at in order to make their money. Conspiracy Theory

krzyray

I'm driving a Toyota Solara (4-cylinder), it takes 4 qt. I've been using Mobil 1 Synthetic since 10,000 miles, and I have over 50,000 right now. I usually change my oil somewhere between 3,000 and 4,000 - and I measure the amount of oil drained, I get about 4 qt back which is good.

I've changed it between 5,000 and 6,000 miles 1 time before, and I only got 3 3/4 oil drained when measured. Plus I also notice the car doesn't perform as well.

I do drive my car pretty hard (flooring at each light and freeway ramp). I'm guessing that's why I need to change earlier than most people, but also after draining the oil I can tell it's much darker than fresh oil - which shows that it needs to be changed.

Any comments?

nothere

iTrader: (23)

I have heard that the detergents are so aggressive they actually
etch the metal. That is why constantly renewing the oil has side effects.

colateralgees

howdy, Winston..."long time no see"!...

actually, the recommended oil change interval on my '89 928 S4 is also 15,000 miles...but like you in AZ, I wouldn't wait that long in West Texas, for the same reasons....I use Mobil 1 typically, and I'll change at 5k to 6k, or once a year, period...

en1gma19

iTrader: (23)

My pops' '03 911 has almost 7200 and hasn't been in for it's first oil change yet either.

colateralgees

I don't quite buy it...not yet anyway.

First of all, they don't offer any explanation as to WHY the oil supposedly protects better once it "gets some age on it." I have a couple questions: Sure, if you look at their test numbers for "0 miles" and then "1,000 miles," there appear to be some relatively notable increases in certain constituents such as copper, a wear indicator. Well, they tested "virgin oil" at "0 miles," which I take to mean right out of the oil container, before it's even been in the car. Note the car had almost 10,000 miles on it when they started the test. How well did they flush the engine when they added the "virgin oil" and started the test? Are the jumps in some constituents at the "1,000 mile" test an indicator of wear that occurred before the test oil was added, and remnant in the previous oil? I'm just asking, that's all.

To "prove" their contention that more wear occurs in the first 3,000 miles, they should have flushed the system after the 18,000 miles and then re-run the test with the same oil and overall regimen. If they are correct, then there should be another spike of wear indicators in the first 1,000 miles of the second phase of the test.

I'm not saying 3,000 mile oil changes are necessary to get the best protection, especially if you use quality oil and filtration and your engine is in decent shape. But combustion by-products include acids and other problematic compounds that need to be removed, and you do that by changing your oil and filter. Same goes for the insolubles...i.e., grit....that can etch bearing and other surfaces.

My 1989 928 calls for 15,000 mile intervals in normal use, and came filled from the factory with Shell dino juice. Maybe that's fine. But I don't believe that using a current, good quality synth like Mobil 1 and changing the oil and filter every 5,000 miles is doing any damage.

If I'm wrong, I'll be the first to save the money and change my ways. But I need more than this to convince me to "let my oil get some age on it."