Urban Coyote Posted December 29, 2005 Share Posted December 29, 2005 Hi Guys, I was just out doing an oil change when I took a look at the oil I had bought. It's Mobil1 5w-50 synthetic. Now that I'm done kicking myself for not looking more closely when I bought it, can I use it in my legacy?? There's a garage within walking distance, so I can go over and buy some 5w-30, but if I can use the 5w-50 I will. Thanks! Urban Coyote Link to comment Share on other sites More sharing options...
Jerry DeMoss Posted December 29, 2005 Share Posted December 29, 2005 I think you should be ok.I like the fact that synthetic is really thin oil and flows really well. Link to comment Share on other sites More sharing options...
Urban Coyote Posted December 29, 2005 Author Share Posted December 29, 2005 I think you should be ok.I like the fact that synthetic is really thin oil and flows really well. I just called the two local Subaru dealers in town and they didn't recomend using it. Said it was too thick and definitely not for Canadian winters. I'll have to hoof it down to the local garage to pick up some 5w-30...sheesh. Think I'll go kick myself some more for not looking, more closely! On the bright side, I'll be working off all those Christmas goodies this way! Urban Coyote Link to comment Share on other sites More sharing options...
Setright Posted December 29, 2005 Share Posted December 29, 2005 Yeah, considering your location, 5W-30 is probably best. 5W-50 is only really suited in light frost, and of course summer! Link to comment Share on other sites More sharing options...
zyewdall Posted December 29, 2005 Share Posted December 29, 2005 In winter time, yeah, it sounds a little thick. 5W40 or 0W40 is what I usually use. In summertime, I don't run anything less than 50 in my car. Keeps it from burning quite as much. Keep it around for the next oil change going into the summer. Link to comment Share on other sites More sharing options...
86subaru Posted December 29, 2005 Share Posted December 29, 2005 i just put in wal-mart brand 10-w30 , seems like some wal-marts pulled it from there shelves , all i can find was a 5qt jug Link to comment Share on other sites More sharing options...
bulwnkl Posted December 29, 2005 Share Posted December 29, 2005 Are you sure it's 5W50 and not 15W50? M1 does not list a 5W50 product for any of North America. I would suggest that a 15W is too thick for Nova Scotia winters. Shouldn't be a biggie next summer, though. Link to comment Share on other sites More sharing options...
zyewdall Posted December 29, 2005 Share Posted December 29, 2005 Are you sure it's 5W50 and not 15W50? M1 does not list a 5W50 product for any of North America. I would suggest that a 15W is too thick for Nova Scotia winters. Shouldn't be a biggie next summer, though. Hmmm. I'm pretty sure I've gotten it before, perhaps from Quaker state or Chevron though. ?? Link to comment Share on other sites More sharing options...
blitz Posted December 29, 2005 Share Posted December 29, 2005 Are you sure it's 5W50 and not 15W50? M1 does not list a 5W50 product for any of North America.XOM offers the 5W-50 in place of the 15W-50 in certain locations, but I couldn't tell you specifically where. Link to comment Share on other sites More sharing options...
OB99W Posted December 30, 2005 Share Posted December 30, 2005 I was just out doing an oil change when I took a look at the oil I had bought. It's Mobil1 5w-50 synthetic. Now that I'm done kicking myself for not looking more closely when I bought it, can I use it in my legacy?? There's a garage within walking distance, so I can go over and buy some 5w-30, but if I can use the 5w-50 I will.Multigrade oils start off with a base stock, and then VI (viscosity index) improvers are added. An oil with a "5W" rating (the "W" is for "winter") has a 5-weight base, and will be free-flowing at low temperatures, whether the VI improvers make its high temp characteristics equivalent to a 30-weight or a 50-weight oil. So viscosity under cold conditions should not be an issue with 5W-50. What will be affected is a warm/hot engine; 30-weight is certainly going to be thinner than-50 weight. Manufacturers have typically specified 30 for the high-temp weight because nowadays they are concerned about gas mileage as well as lubrication. Using 5W-50 shouldn't affect cold weather starting, etc., but it could cause your mpg to decrease, and it might not as readily lubricate small spaces. In general, sticking with the manufacturer's recommendations makes sense, unless the engine is so worn that a higher-viscosity oil becomes beneficial. Link to comment Share on other sites More sharing options...
Urban Coyote Posted December 30, 2005 Author Share Posted December 30, 2005 Hi Guys, Thank you very much for the advice. I went on the safe side and hiked over to the local garage and picked up some 5w-30 synthetic. I don't want to take any chances with my new Legacy (new to me anyway, it's a '98) Yup, it's definitely 5w-30....but I typed in the wrong manufacturer. It was Formula1, not Mobile1. I'm doing great these days eh? *lol* Happy New Year Everyone! Urban Coyote Link to comment Share on other sites More sharing options...
Commuter Posted December 30, 2005 Share Posted December 30, 2005 OB99W is on the mark. I've been using 5W50 oil in S. Ontario for years now. No problems. In general, it is ok to go "outside" the manufactures recommendation (below the W number, or above the higher number). What you don't want to do is to go inside. Eg, don't put 5W20 into an engine that lists 5W30. If you go lower, the oil will flow freer for cold starts etc, but the engine might be a little noisier. If you go higher, you are giving yourself more of a safety factor. It's not so much that the oil is thicker, but rather that it doesn't thin out as quickly at higher temperatures. And that means better protection. Have you ever seen oil at 200F or so? It is like water! Even the 5W50 stuff. (I was playing around with a few ounces of different oils in tins in the oven a few years ago, but it was stinking the place up at 300F and I had to abort.) Ford and Honda switched to the 5W20 stuff a few years ago. Apparently, they both dropped their expected engine life numbers considerably in their government submissions (some EPA thing I believe). So why did they do it? Because you get 0.1 to 0.2 mpg better gas mileage. D'oh! A friend of mine went through quite an ordeal with Honda to finally get a letter from them saying that it is "ok" to use 5W30 oil in his new (2002 or 3?) Civic. Hmmm. Commuter Link to comment Share on other sites More sharing options...
Setright Posted January 1, 2006 Share Posted January 1, 2006 NO! A 5W-30 and a 5W-50 oil will NOT have the same low temperature viscosity. If you really are serious about selecting oil, read the spec sheets. The "xW-xx" is just a general range, not an accurate gauge. Link to comment Share on other sites More sharing options...
OB99W Posted January 1, 2006 Share Posted January 1, 2006 NO! A 5W-30 and a 5W-50 oil will NOT have the same low temperature viscosity. If you really are serious about selecting oil, read the spec sheets. The "xW-xx" is just a general range, not an accurate gauge. Setright, I think your info on how to avoid problems when filling a Subaru cooling system is excellent. I don't mean to pick on you, but we apparently have differing viewpoints on oil viscosity, and it seems to go beyond semantics. Perhaps I can offer something when it comes to oil viscosity, and in particular multi-vis. VI improvers are long-chain polymers that are designed to "coil up" and affect viscosity very little at cold temps. At high temps, they "uncoil" (becoming longer), effectively "thickening" the oil. (Some full synthetics technically don't use what would be classified as VI improvers because their chemistry means they inherently don't thin as conventional oils do.) The "W" (winter) viscosity ratings are currently based on SAE J300. It actually doesn't allow for much range if an oil is to meet the "5W" standard. In fact, an approximately 5% shift in viscosity (with an attendant 5 degC change in temperature), depending on direction, moves a "5W" oil to either "0W" or "10W". In order to make this somewhat less lengthy, please refer to Table 1 from this web page: http://www.texacoxpresslube.com/carcare/article_viscosity.html A couple of points of reference: 1) The unit of viscosity "cP" is "centipoise", also equivalent to "mPa-s" or "millipascal-seconds". 2) To get a feel for cP, water's viscosity at 20 degC is very slightly over one (1), at 1.002 cP. Looking at the table, note that cold cranking viscosity for 5W should be less than 6600 cP at -30C, and that 6200 cP at -35 makes it 0W, while 7000 cP at -25C conforms to 10W. So, the spec is not all that loose at low temps, and the high-temp viscosity (of the "-xx" part of "xW-xx", as it was referred to by Setright) has no bearing on this. You can also see from the table that the high-temp viscosity is, of course, different for 30/40/50 weight oils. Taking into account the high-temp aspect of certain multi-viscosities, they're listed in the right-hand-most column. By the way, "cSt" is "centistokes". So, I'll stick with what I said before; 5W-50 and 5W-30 oils (assuming they aren't mislabled) should have fairly similar 5-weight viscosity characteristics at sufficiently cold temperatures. At high temps, they will take on the character of 50- and 30-weight oils, respectively. As I also said previously, I'd go with the manufacturers recommendations (unless the engine is being run outside the temp range that the manufacturer specs or it has looose-fitting parts due to excessive wear). Sorry for the length; hope it clarified things for some. Link to comment Share on other sites More sharing options...
Setright Posted January 1, 2006 Share Posted January 1, 2006 Yeah, I am sorry about that. Sometimes when I'm in a hurry, I tend to lose any sense of diplomacy :-) But I do stand on my viewpoint: Mobil 1 5W-50 cSt @ 40 C 104.9 cSt @ 100 c 17.5 Compare to M1 5W-30 cSt @ 40 C 72.8 cSt @ 100 C 12.1 *Sourced from MobilEurope.com I know that you might say 40 degrees C is somewhat higher than where the "5W" is measured, but if you start digging into the spec sheets, you will graphs that indicate that 5W-50 has a higher viscosity further down too. Link to comment Share on other sites More sharing options...
OB99W Posted January 1, 2006 Share Posted January 1, 2006 Yeah, I am sorry about that. Sometimes when I'm in a hurry, I tend to lose any sense of diplomacy :-) But I do stand on my viewpoint: Mobil 1 5W-50 cSt @ 40 C 104.9 cSt @ 100 c 17.5 Compare to M1 5W-30 cSt @ 40 C 72.8 cSt @ 100 C 12.1 *Sourced from MobilEurope.com I know that you might say 40 degrees C is somewhat higher than where the "5W" is measured, but if you start digging into the spec sheets, you will graphs that indicate that 5W-50 has a higher viscosity further down too. Okay, thanks; I much prefer a discussion based on technical info . It's obvious that at the temps you've provided data for, the 5W-50 is more viscous. But I didn't say otherwise (and in fact that's why I suggested all along sticking with the recommended weight). Even without seeing the data, I'll give you that the 5W-50 is likely somewhat more viscous "further down" as well. However, it shouldn't be so viscous at cold temps that it couldn't legtimately be called "5W", or somebody is cheating. We seem to have gotten somewhat "deep", but I think the practical aspect for most drivers would be if at cold temps an oil sufficiently slowed cranking or decreased pumping such that the engine was difficult to start or was poorly lubricated. With full synthetic, as long as we're talking a reasonable temperature above the pour point, either 5W-50 or 5W-30 shouldn't present a problem in that respect. For conventional oils, it might be a bit more of a concern. Can we compromise on the above, because now I think it really is coming down to semantics? Peace . Link to comment Share on other sites More sharing options...
Setright Posted January 2, 2006 Share Posted January 2, 2006 Sure :-) These text based discussions can get heated far beyond the intent, since you can't see if people are smiling and twinkling their eyes. Just for info:I am running 5W-30 now, during winter, but in summer I will switch to 5W-50. The thing I need to consider is that a lot my daily work related trips are only about 5-6miles, so the oil never reaches it's full op temp and that means pumping "losses" with the thicker stuff. No, no, no, I am not a last-word guy Link to comment Share on other sites More sharing options...
frag Posted January 2, 2006 Share Posted January 2, 2006 No, no, no, I am not a last-word guy Done! Link to comment Share on other sites More sharing options...
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