geckolizard Posted June 3, 2004 Share Posted June 3, 2004 Greetings, I bought a '04 Forrester XT in Aug. After 1,500 miles I replaced the oil with Mobil 1 5W30. After a couple of oil changes, I have noticed significant oil consumption. (A quart every 3,000 miles) Could this be due to the fact that my valves haven't seated due to insufficient break-in. Any thoughts or suggestions would be appreciated. P.S. Should I change back a conventional oil to allow them to seat? Thanks, Geckolizard Quote Link to comment Share on other sites More sharing options...
99obw Posted June 3, 2004 Share Posted June 3, 2004 At the risk of being flamed by all of the loyal Mobil 1 fans out there, Mobil 1 5w-30 is a good oil, but it's WAY too thin. It's almost a 20 weight before any shearing. My experience has been that the EJ25 prefers an oil closer to 12 cSt, like Amsoil ASL 5w-30 or Pennzoil HM 5w-30. The German made Castrol Syntec 0w-30 is supposed to be close to 12 cSt. If it were my XT I would be running the Amsoil ATM 10w-30, for summer at least, or maybe the GC 0w-30 year round at 5k intervals. I personally wouldn't run a conventional oil in a turbocharged engine, but I am an oil nut, so take that FWIW. Apples and oranges, but our NA EJ25 at ~160k miles is using about 1 quart every 7500 miles of Amsoil ASL, even less with the ATM. Quote Link to comment Share on other sites More sharing options...
Strakes Posted June 3, 2004 Share Posted June 3, 2004 Asking for oil opinions is like opening a can of worms... I've been using Mobil 1 15W50. Very little oil consumption at 30000+ miles. In my manual, it states that you can use a 10W50 or a 20W50 if use use your car for "heavy-duty" applications. I had a similar oil consumption problem to yours in a turboed car that I used to have. I tried Castrol Syntec 5w30 and Mobil 1 5w30 had to add a quart every 1500 miles, until I switched to 15W50. I've heard that if you can get a heavy duty diesel synthetic 5W40 (which are also approved for gasoline engines) that the oil consumption goes down considerably and you benefit from better fuel efficiency also. Some people like Mobil 1 Delvac 5W40 Synthetic a lot....it's just harder to find where I live. Quote Link to comment Share on other sites More sharing options...
99obw Posted June 3, 2004 Share Posted June 3, 2004 Good advice on the 5w-40. I am going to be switching my jeep over to Amsoil 5w-40 AFL soon, probably the subaru at 200k miles or so. Walmart has Rotella-T "Synthetic" 5w-40, ~$13.00 a gallon FWIW. Not as good as Delvac 1 but pretty good none-the-less. Quote Link to comment Share on other sites More sharing options...
geckolizard Posted June 3, 2004 Author Share Posted June 3, 2004 So, the thinking here is that Mobil 1 5W30 is too thin and that a "thicker" oil would cut down on oil consumption. I have used Rotella 15W40 in diesel tractors and they have run well. So maybe the 5W40 Rotella Synthetic is worth a try. Quote Link to comment Share on other sites More sharing options...
JBRIII Posted June 4, 2004 Share Posted June 4, 2004 Mobil1 has a new 5W40 Synthetic Truck & SUV Oil. It is repackaged Delvac1. I have found it at Advanced Auto Parts when I've been traveling for work. But none locally yet. Just hit the shelves in March. Some guys on Bob's site are reporting it at WalMarts already. John Quote Link to comment Share on other sites More sharing options...
geckolizard Posted June 4, 2004 Author Share Posted June 4, 2004 Mobil1 has a new 5W40 Synthetic Truck & SUV Oil. It is repackaged Delvac1. I have found it at Advanced Auto Parts when I've been traveling for work. But none locally yet. Just hit the shelves in March. Some guys on Bob's site are reporting it at WalMarts already. John Many Thanks! Quote Link to comment Share on other sites More sharing options...
Strakes Posted June 4, 2004 Share Posted June 4, 2004 JBRIII: Thanks, that's good news. I've wanted to go to Mobil-1 5W40 for a long time now, but just couldn't find the stuff anywhere...I'll keep an eye out next time I go to the store. Quote Link to comment Share on other sites More sharing options...
JBRIII Posted June 4, 2004 Share Posted June 4, 2004 I'm going to use it in the wife's new 05 OBW as soon as I hit 3k. Stocking up as I find it. Traveling again this week, so hopefully I can get some more. John Quote Link to comment Share on other sites More sharing options...
Setright Posted June 6, 2004 Share Posted June 6, 2004 I have said it before, and I will say it again: Why doesn't Mobil sell the 5W-50 stuff in the states? This rating doesn't evapourate off cylinder walls like the watery xW-30'ies, and consumpion is barely detectable. Do you guys have the 0W-40 that I use here for winter? Quote Link to comment Share on other sites More sharing options...
hohieu Posted June 6, 2004 Share Posted June 6, 2004 I just thought I'd give my 2 cents. With a 5W/40 oil, I imagine that VI improvers are added to the oil. Mobil 1 does not use VI improvers in their 5W/30, whereas Amsoil formulates their 5W/30 and 10W/40 with VI improvers. Hence, I would guess that Rotella 5W/40 (or any 5W/40 oil) uses them as well. Oils that use VI improvers are more prone to viscosity and thermal breakdown, and will not retain their viscosity as well as one that uses fewer or none at all, but this comes into play only if you are using extended drain intervals. There is an ongoing study comparing Amsoil/Mobil 1 5W/30 oils, and I would predict that the Amsoil will not hold up as well as the Mobil 1 for this very reason; you can check it out for yourself http://neptune.spacebars.com At 75,000 miles, my car consumes less than .5 qt. of M1 5W/30 every 3K miles so I will continue with my existing regimen. I believe Subaru says that 1 qt. of oil every 1,500 miles is acceptable, though I would tend to disagree. But if you are concerned about oil consumption, why not switch to M1 15W/50, which has a pour point well below many conventional 5W/30 oils. I run it in my motorcycle and myles runs it in his Legacy (see "Record Fuel Milelage" Thread). I suggest this because my only reservation concerning oils forumulated for diesel engines (i.e. Rotella) would be fouling the catalytic converter, which, of course, diesel engines do not have. Shell even warns about usage of their 15W/40 oil in cars on their webpage for this very reason, but I am not sure about their sythetic 5W/40 formula. I am a bit of an oil nut myself because I own a motorcycle, and do you know that Honda, Suzuki, Yamaha, BMW, and other motorcycle manufacturers charge $4-6 for rebadged conventional oils and $8-12 for rebadgedsynthetic oils? 5W/30 and 10W/30 oils with "Energy Conserving" contain molebdenum, which allegedly causes wet clutches to slip, but this is an entirely different story... Quote Link to comment Share on other sites More sharing options...
myles Posted June 6, 2004 Share Posted June 6, 2004 Mobil 1 does not use VI improvers in their 5W/30 According to an email I received from Mobil1 "tech support", all Mobil1 motor oils contain VI improvers. I was once told that the 10w30 did not, but all others did. Who knows? Quote Link to comment Share on other sites More sharing options...
hohieu Posted June 6, 2004 Share Posted June 6, 2004 According to an email I received from Mobil1 "tech support", all Mobil1 motor oils contain VI improvers. I was once told that the 10w30 did not, but all others did. Who knows?Who really does know? Thanks for the information, I was told by Mobil that they didn't, but this was some time ago ... and the M1 supersyn formulas are relatively new. Quote Link to comment Share on other sites More sharing options...
Ratty2Austin Posted June 6, 2004 Share Posted June 6, 2004 Hi, I work in the oil change dept. at Carter Subaru, and I have actually heard this complaint before from a few people (loosing oil up to a Qt. between oil changes) Subaru claims that due to the motor design, tolerances allow for up to 1qt loss of oil between oil changes (every 3k), which is supposed to be "normal". in my own opinion, I would just keep using the oil as normal (the suggested 5w30 syntec or whichever you prefer) and check the level on occation and top off as needed. Quote Link to comment Share on other sites More sharing options...
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