vince@fluke.UUCP (10/19/84)
>> Also, if synthetic oils are so wonderful, why do most >> manufacturers warn that they will not stand behind their >> warantees if you put synthethic oil into your engine? > Easy. They are VERY conservative. Petrol-based oil is well-known. > They KNOW how it works, they know how their engines will react to it. > Synthetics are a relative new-comer. Their properties aren't so > well-known. They may be better, they may be worse. Maybe they're > better (than conventional oils) for some engines but worse for others. > They haven't had time to test them sufficiently to trust them. > Sticking with conventional oils is safe, so that's what they do. Synthetic oils are not as new as you may have imagined. A friend who is an aviator informed me that synthetic oils have been used in planes for ages (I think he said decades). Synthetic oils (which brands I don't know) are approved by both the FAA and aircraft engine manufactures for use in most if not all aircraft. This is a VERY CONSERVATIVE industry. If there were any doubt at all about its reliability, it would not be approved. I was certainly impressed by this fact before I began using Mobil 1 in my car. I am convinced that most cases where synthetics are discouraged are because of ignorance or because of alterior motives (would like to sell you more service). Perhaps if there are some fellow netters out there who know more about the aviation end of things, how about filling us in? Craig Johnson uw-beaver! \ John Fluke Mfg. Co., Inc. decvax!microsof! \ Everett, Washington ucbvax!lbl-csam! > fluke!vince allegra! / ssc-vax! /
graham@orca.UUCP (Graham Bromley) (12/07/84)
I'm a bit puzzled by all the discussion about use of Mobil 1 synthetic oil (5W-30) in cases where the owner's manual requires 10W-30 or 10W-40, as they usually do. Surely the best thing is to simply use a good quality oil of the recommended weight and change oil and filter as specified, or more frequently if you really want to. Why risk voiding your manufacturer's warranty? No magic oil will prevent your engine from gradually wearing out. (The body will probably rust out first anyway). As for Mobil 1 lasting 25000 mi between changes, don't you believe it. The oil molecules themselves might, but long before then the oil will be polluted with minute metal particles from engine wear and combustion blow by etc., especially if the engine is new or rebuilt. If you are are really concerned about engine life, just do as the manual says. Oil and filter every 7500 mi seems to be the norm (for Japanese cars at least).
ems@amdahl.UUCP (E. Michael Smith) (12/10/84)
> > Why risk voiding your manufacturer's warranty? No magic oil > will prevent your engine from gradually wearing out. > (The body will probably rust out first anyway). Not in California (or any other state civilized enough to keep their salt in salt shakers on the dinner table). :-) -- E. Michael Smith ...!{hplabs,ihnp4,amd,nsc}!amdahl!ems No one would dare claim these opinions.
vince@fluke.UUCP (Craig V. Johnson) (12/12/84)
> As for Mobil 1 lasting 25000 mi between changes, don't > you believe it. The oil molecules themselves might, but long > before then the oil will be polluted with minute metal particles > from engine wear and combustion blow by etc., especially if > the engine is new or rebuilt. If you are are really concerned > about engine life, just do as the manual says. Oil and filter > every 7500 mi seems to be the norm (for Japanese cars at least). The problem with running Mobil 1 for extended mileages is not with particulate contamination (that's why you change your filter every 7-10K miles), but with chemical contamination mainly in the form of sulphuric acid. The acid is formed in the crankcase as a side affect of combustion blow-by (gasoline contains trace amounts of sulphur). All quality motor oils contain acid neutralizing agents and I'm sure Mobil 1 is no exception. However, this additive is consumed with time, and fresh oil is necessary to replenish the additive. My car is consuming about 1 quart of Mobil 1 every 2500 miles. At this rate I would consider changing the oil at over 20K miles, particularly if I drove that many miles annually. However, I do not drive more than about 10K miles annually and between additive deterioration with time and the fact that I get a lot of moisture build-up in the engine during the winter, I have chosen to change my oil annually, usually toward the latter part of the winter. Two properties of Mobil 1 in addition to the extended change period are worth noting. First, the film strength of Mobil 1 is much greater than conventional oils. This allows the oil to protect much better even at a considerably lower viscosity. This leads to the other benefit. Since the viscosity may be lowered, the engine expends less energy sloshing it about, and this is the main reason behind the increased gas mileage claims. Also, the viscosity vs. temperature curve for the synthetic is much flatter than for conventional oils. This means it is much thinner (and cars start easier) at low temperatures, and it is much thicker (again better protection) at higher temperatures. Mobil 1 also does not break down into the elements that cause sludge and varnish deposits as do conventional oils. By the way, a while back when I posted a message about Mobil 1, I mentioned that the viscosity had been changed. I have since checked it out and now can report with certainty that Mobil 1 was originally 5W-20 and is today 5W-30. I have no doubts that this was in response to complaints Mobil received about excessive oil consumption. The 5W-20 did indeed leak and/or get blown out the exhaust quickly. My experience is that the 5W-30 is consumed at only about 1/2 the rate that the 5W-20 was. Watch out what you are buying, both types are still in circulation. I just saw both kinds at a service station along I-5 north of Bakersfield last weekend (12/9). Craig Johnson uw-beaver! \ John Fluke Mfg. Co., Inc. decvax!microsof! \ Everett, Washington ucbvax!lbl-csam! > fluke!vince allegra! / ssc-vax! /