grl@drutx.UUCP (LymanGR) (11/26/85)
Having paid an arm and a leg for an oil change using MOBIL 1 synthetic motor oil, I am curious about how long this stuff really lasts. I purchased the 5W-30, which is working nicely with the weather I've been experiencing (15 degrees F). However, the owner's manual recommends that 5W-30 be used only up to 60 degrees F. Does this mean that I should change the oil next summer? MOBIL states that the oil is good for 24,000 miles or one year (whichever comes first). What do YOU think? drutx!grl Randy Lyman
grd@ihu1e.UUCP (daly) (11/27/85)
> > > > Having paid an arm and a leg for an oil change using MOBIL 1 > synthetic motor oil, I am curious about how long this stuff > really lasts. I purchased the 5W-30, which is working nicely > with the weather I've been experiencing (15 degrees F). > However, the owner's manual recommends that 5W-30 be used > only up to 60 degrees F. Does this mean that I should change > the oil next summer? MOBIL states that the oil is good for > 24,000 miles or one year (whichever comes first). > > What do YOU think? > > drutx!grl Randy Lyman > I wouldn't know. From the tests I've run on synthetic oil, I've found that they have WORST lubricative capabilities as compared to other pertroleum base stocks. What makes these oils better is the additives they add to the oil. Sythetic oils do withstand higher and lower temperature ranges as NASA does use them but they do not have the lubricative capability as does base stock oils. All in all, the synthetics will last as long as the additives will. I would get an in writing guarantee of full replacement of my engine before I would stick this stuff in my car. - Garry Daly ihu1e!grd
pwv@fluke.UUCP (Pat Vilbrandt) (11/27/85)
> Having paid an arm and a leg for an oil change using MOBIL 1 > ... MOBIL states that the oil is good for > 24,000 miles or one year (whichever comes first). > > What do YOU think? > > drutx!grl Randy Lyman I believe Mobil. Let me digress a minute however on a recent experience with organic motor oil: A friend called me the other day saying the engine in his '82 Subaru was making horrible banging sounds, so he towed it to my house, and sure 'nuff, it sounded horrible. What's the problem? Quick compression check; one cylinder slightly low, but acceptable overall. So, we undid 80,000 hoses and tubes and pulled the engine out. (It was obvious by now from turning the main engine pulley by hand that the connecting rod bearings were shot -> lots of play.) As we here tearing the heads down, we found that they were full of gunk - looked like asphalt (which is, after all, one of the "bottoms" left over from refining lubricating oil from crude). Hmmm, I thought. So I asked my friend, "How often have you changed the oil in this puppy?" He slowly cleared his throat and said quietly "'bout four or five times." The car had 103k miles on it! Enough of this "asphalt" had found its way into the oil pan to plug the oil intake screen. No oil pressure -> trashed bearings. Today, after machining the crank, re-conditioning the conn. rods and new bearings (and scraping lots of gunk!), my friend's Subaru is back on the road. The moral of this (true) story is that ORGANIC motor oils have to be changed often because they BREAK DOWN. This break down is largely caused by heat, not from combustion by-products, dirt, dust, water, whatever. Most of the additives (detergents) put in organic motor oil are there to combat this problem, ie. to protect the engine from the oil! True, the above is a bit extreme, but I question the recent practice of many auto manufacturers extending oil change intervals to 10,000 miles. Organic oils just haven't improved that much. Don't believe me? Well, let me offer this other true story: I started running Mobil 1 in my '77 Subaru 4WD wagon after the first 6000 mi. oil change, and changed it thereafter every 15-20K miles. At about 90k miles, the water pump seal failed, the engine lost coolant and the *cylinders* warped. In the process of tearing the engine down to have the cylinders re-bored, I found almost no bearing, ring or cylinder wear and the engine was the cleanest I had ever seen - no sludge build up in the heads and almost no varnish! I got the impression that the engine would have gone forever if it hadn't overheated. Note that I had driven the car in temperatures over 100 degrees in the summer and below zero in the winter. Also, back then, Mobil 1 was 5W-20, not 5W-30 as it is now (which I believe is better). Well, this is getting too long, so, in summary, if you're using Mobil 1, you'll be okay if you change it every 24,000 mi. If you're using organic motor oil, change it as often as you can afford, every 5,000 is probably okay, more often is better. -- Pat Vilbrandt John Fluke Mfg. Co., Inc. Everett, Washington USA UUCP: { decvax!uw-beaver, ucbvax!lbl-csam, allegra, ssc-vax, decwrl!sun }!fluke!pwv ARPA: fluke!pwv@uw-beaver.ARPA
levy@ttrdc.UUCP (Daniel R. Levy) (12/03/85)
In article <711@drutx.UUCP>, grl@drutx.UUCP (LymanGR) writes: >Having paid an arm and a leg for an oil change using MOBIL 1 >synthetic motor oil, I am curious about how long this stuff >really lasts. I purchased the 5W-30, which is working nicely >with the weather I've been experiencing (15 degrees F). >However, the owner's manual recommends that 5W-30 be used >only up to 60 degrees F. Does this mean that I should change >the oil next summer? MOBIL states that the oil is good for >24,000 miles or one year (whichever comes first). > >What do YOU think? > >drutx!grl Randy Lyman > Certainly follow the owner's manual scrupulously if the engine is still under any kind of extended warranty, such as many modern models have. Depends on the kind of car you have, too, whether you would wish to risk the 5w30 during warmer temperatures. It might not be wise in, say, a turbo engine to do this. In my ancient Chevy Vega, the manual says that a 5w30 oil is safe clear up to 100 degrees Fahrenheit, and Mobil 1 works nicely in that infamous engine (though with some leaks; the stuff gets past gaskets a lot more freely than conventional oils, it seems). If you are worried about temperature ranges, and the oil is still apparently clean come warm weather, you could always save it in a clean, covered con- tainer (clean the bottom of the oil pan too before draining). My main concern is that the oil gets grungier and grungier with suspended combustion products and carbon with use, and I don't like to have too much of this circulating about the engine even when passed through the filter to remove granular par- ticles, though I have seen stories in various mechanical magazines which claim all sorts of long life for this oil and I think it's probably true. If you can change it yourself at all it will be a lot cheaper, obviously, to change it fairly often (you may also do a more conscientious job yourself; a lot of garages don't even wait to let the last half quart or so of oil out before closing up the drain and adding the new oil). 'Nough foaming at the mouth for now, gotta go.... -- ------------------------------- Disclaimer: The views contained herein are | dan levy | yvel nad | my own and are not at all those of my em- | an engihacker @ | ployer or the administrator of any computer | at&t computer systems division | upon which I may hack. | skokie, illinois | -------------------------------- Path: ..!ihnp4!ttrdc!levy
levy@ttrdc.UUCP (Daniel R. Levy) (12/04/85)
In article <559@ihu1e.UUCP>, grd@ihu1e.UUCP (daly) writes: >From the tests I've run on synthetic oil, I've >found that they have WORST lubricative capabilities as compared to >other pertroleum base stocks. > > - Garry Daly ihu1e!grd Please describe these tests for us? -- ------------------------------- Disclaimer: The views contained herein are | dan levy | yvel nad | my own and are not at all those of my em- | an engihacker @ | ployer or the administrator of any computer | at&t computer systems division | upon which I may hack. | skokie, illinois | -------------------------------- Path: ..!ihnp4!ttrdc!levy