absolutely. right now though, it's not even on the radar screen, let alone being addressed.
i don't know for sure, but i suspect it's fairly common with some brands. i used to use honda branded filters for example, but discovered by mistake that their drain-back valves appear to be pretty much useless. or at least, at the time that i was using them. if you warmed up the engine prior to oil change, then left the car to sit for an hour, the subsequent filter change involved no spillage. zero. the filter would be absolutely empty. every filter, every time. this is great if you don't want the honda problem of oil spillage over the exhaust and is arguably a "useful" feature (!), but it's not good for internal engine health. currently i'm using cheapo walmart brand made by champion labs, and despite their price, they've turned out to be much better, though i did have one that seemed to leak.
there are a number of other write-ups about this on the web. e.g.
i agree. but then we run into the fact that he changes the oil, mobil 1 no less, at only 3k miles....
Run the numbers for average temperatures from April to November in Southern Ontario where Tegger says on his web site that his car resides. We are talking about a change in average temperature of around 27 degrees F. The difference in oil volume with a change in temperature of about 30 F is about 0.045 quart. This is comparable to the reading error. Plus, like reading error, with enough readings, it is going to average out.
Except that in the real world it makes no significant difference in terms of accuracy. It takes hours for oil that is in the bearings, oil passages to the bearings and head and other crankcase locations to drain back to the pan. That means that in many engines you get the exact same reading when you check the oil a couple of minutes after hot engine shut down as you do when it sat over night.
Anybody with a brain and sufficient curiosity will easily determine on their own how this works. If you check the oil every 30 seconds after a hot shut for a period of hour (about 120 dipstick checks) you will be convinced that the reading is constantly changing.
Yes and that in and of itself should make anyone suspicious of the methods used to acquire the data.
There is an obvious bias in the way the measurements were made. The miles/qt is almost always around 400 miles less for the measurements labeled 1st than for the measurements labeled 2nd. There is not enough info to determine exactly what the source of that bias is. All that can be said is it is extremely unlikely that an honest and accurate accounting of how much oil this engine consumes would show that the oil is being consumed at a slower rate the longer it stays in the crankcase.
It may be interesting to graph each 1k miles separately to see the trends when you have enough data. Since we now know that there is a difference of 0.039% volume change per degree F, you could use that in your spreadsheet calculation if you so desired.
Here is a fairly simple explanation about oil and evaporation
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I do know that hygroscopic polymers (petroleum based products) absorb moisture, and to remove it prior to processing it needs to be driven at a specific temperature (temperature dependent on type of polymer and time), in a -40°c or lower dew point system that has the ability to either absorb the moisture through desiccant, or exhaust it (compressed air drying systems). If there is no way for the moisture to be absorbed or escape, it will not "dry" or removed.
"Stewart" wrote in news:i0q3bk$ts8$ snipped-for-privacy@news.eternal- september.org:
I do have all the the ambients when checked at start/end, so I could make a graph revision incorporating that.
Nice.
ASTM D-5800 is desgned to specifically address evaporation, as I outlined in a recent post entitled, "Oil "volatility"/"evaporation": The REAL story".
API SM-graded engine oils are refined to the point where volatiles that might boil-off (above the standard) are removed during the manufacturing process.
Oil and water don't mix, officially. Do you maybe mean that they form emulsions with moisture?
They absorb. Don't forget that even though they start with petroleum based stock, they are highly modified and merged with a wide range of monomers and chemicals during the polymerization process.
Polyurethane, Polyamides (nylons), PET, Polycarbonate, Butyrate to name a few. Some that don't absorb would be PVC, POM (delrin), Polyethylene, Polypropylene. Of course any that do not absorb, excessive surface moisture can be an issue due to condensation (cold trucks/warm warehouse), so some processors may "dry" all materials, or at least preheat them.
Most will absorb at a rate of about .1% per hour at 50% RH until they reach an equilibrium. Saturation levels are usually at about .25% at extremely high RH, though lowering ambient RH does not lower resin moisture content. Most manufacturers will usually specify a maximum for processing at .03%, though that is usually in an industrial setting with high output rates and the material is resident in the processing system for seconds.
In the medical device arena, extremely small parts mean long residence times (as much as 30 minutes or more), and the moisture levels necessary directly correlate to residence times. I normally specify .005% moisture for many processes, sometimes .000% to avoid hydrolysis that may lead to reduced component integrity.
Of course, the above is only a brief summary.........I have had discussions/debates with contemporaries that have lasted hours on the best methods to achieve proper moisture levels for processing.
they most definitely can mix. there are many examples, but a simple illustration is water and chloroform. they "don't mix", but actually they do for binaries in small percentages, and in the presence of a ternary, in this case acetic acid, they do in large percentages:
there are loads of other examples. motor oil is far from being a simple isomeric hydrocarbon.
"Stewart" wrote in news:i0v7vu$sgj$ snipped-for-privacy@news.eternal- september.org:
Most drink containers are PET, PETE or PC. Oxygen/water transfer is limited by the barrier coating (can't remember its composition just now), but would the substrate actually /absorb/ water in the absence of the barrier coating?
My trade mags tell me that Nestle has had technical challenges with its supplier in its attempts to reduce the weight of its cold-fill plastic bottles. Make the substrate thinner and weaker, and the barrier coating is more difficult to make impermeable.
Hm. Vinyl seems to soak up water like crazy, to my observation. It turns white and swells. The whiteness and swelling stops right at the waterline.
PE is often used for food storage. It /appears/ affected not at all by water, from what I can see.
Polypro floats, and also does not /seem/ to be affected by water. Polypro is used extensively for the sort of pint and half-pint tubs used when you buy potato- and macaroni-salads at the deli. These are, of course, loaded with water.
And what about styrene? PS is ubiquitous in the single-serving drink/pudding/yogurt/cereal market, usually in combination with ultrasonically-sealed lids.
Never heard of that before. My industry has some dealings with food processors. Plastic containers go straight from pallet to packing line, and usually experience no preconditioning of any kind prior to packing, other than a quick washing and drying. The drying is to remove surface moisture, not the moisture inside the material.
For a gallon of motor oil, that would equate to about a third of an ounce, or less than a quarter-teaspoon. You'd never see 1/4 TSP on a dipstick.
Yes, they will absorb to their saturation level...but most drink containers for carbonated drinks are either thicker or (most common) uses a multilayer construction, sandwiching something like EVOH and a polyamide. I believe the plastic beer bottles use up to 7 layers (maybe more now) of PA-EVOH-PA-EVOH-PA, etc...as for an actual vapor barrier coating, I'm not sure what is used for that, as industrial and food packaging are not my area of expertise.
Just making the bottles thinner (from what I understand) was challenging enough. Thin cross sections are prone to pinholes and uneven strain sections. I would think that the material manufacturers had to really tweak the resin formulation as well as advancements in blow molding technology were used to allow the PET bottles to be as thin as they are now.
PVC is polymerized with water. It doesn't usually absorb, and is used for waterproofing things, as well as for water and drain pipes. Other things can cause it to swell, such as pool chemicals (the reason why chemical balancing of a pool is different based on if it uses a liner or not) or if it is not UV stable. Higher temperatures can also cause problems for softer grades. Of course once again, PVC is not my forte' so to speak, as very little of it is used in medical devices.
Wikipedia has some good info on PVC
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Pretty impervious to most things. Even used for underground gasoline storage.
In general polypro and polyethylene have specific gravities of Polypro is used extensively for the sort of pint and half-pint tubs
Styrene will absorb moisture to it's saturation point. It won't "drip through", but it will absorb too much from ambient air to process without drying.
Absorbed moisture needs to be driven out. Most engineering resins specify a -40°c/f (the scales intersect at this point) in a desiccant type system at a specific temperature. The air flow needs to go through the pellets and be fairly well distributed, and the elevated temp drives the moisture from the resin, and then the desiccant absorbs it. Compressed air systems are used more frequently today as well, as the capital investment is much less (no moving parts, no regeneration or changing of desiccant). There are some processors that use a hopper heater for surface moisture on pellets, as well as to generate higher outputs.
I don't think that the absorption rate would apply directly to oil itself, too many other factors involved. The thing about oil losing moisture or evaporation is that the oil system in a vehicle is pretty much a closed system (except for some pollution controls), so I would have to believe there is a good chance most evaporation would be re-absorbed.
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