axxiom Posted April 1, 2005 Share Posted April 1, 2005 I'd like to try Mobil 1 0/40(European Formula) synthetic oil in my 2000 Legacy GT. I've been using synthetic oil, 5/30 and 5/40, (Castrol and Valvoline) since 5000 miles. The car has 39k miles on it. Does anyone see any potential problems using the Mobil 1 0/40 in my Suby? Quote Link to comment Share on other sites More sharing options...
HattoriHanzo Posted April 1, 2005 Share Posted April 1, 2005 I've used Mobil oil products for a long time, and have always been pleased with them, I use synthetics in everything-love 'em, I don't see a problem. Quote Link to comment Share on other sites More sharing options...
cookie Posted April 1, 2005 Share Posted April 1, 2005 If it has always had synthetic you should not have the seal issue and maybe you might pick up a tiny bit of mileage. Let us know how yours acts on it regarding piston slap (louder, quieter, don't have it), and how it affects fuel mileage. Quote Link to comment Share on other sites More sharing options...
Commuter Posted April 1, 2005 Share Posted April 1, 2005 I see you are in Cali, so cold starts should not be an issue. That would be one reason for considering the 0W?? vs a 5W??. The 0W?? oil will flow a little quicker on start up, possibly reducing some long term wear, but I bet that you will notice more piston slap too. Which is worse? Hmmmm... I don't know. Given your climate, I'd personally stick to the 5W?? oil. Go for a 5W40 if you can get it. (I don't recall, does Mobil 1 come in this grade?) Commuter Quote Link to comment Share on other sites More sharing options...
powderhound Posted April 1, 2005 Share Posted April 1, 2005 Yes there is a new "SUV" 5W-40. You can get it at walmart. I mix it 50/50 with 5W-30 for my summer oil. Quote Link to comment Share on other sites More sharing options...
cookie Posted April 1, 2005 Share Posted April 1, 2005 an O grade to start with would be cold cranking, fuel mileage, and power. I personally feel that it is going to protect the engine from scuffing a bit less, but that is just my opinion. I have seen test results that show a small amount of HP to be gained from the lower resistance and heard that it might be benificial for fuel mileage. I suspect the difference between a 5 grade and a zero grade would be hard to measure in everyday driving. I guess you can see from the other thread that I am experimenting with 15-50 in my car and the results seem good for a worn engine. I think that these cars wear the pistons a bit causeing the slapping and I wonder if they could be prevented from slapping if they were run on a scuff resistant oil from new. Quote Link to comment Share on other sites More sharing options...
99obw Posted April 2, 2005 Share Posted April 2, 2005 Mobil 1 0w-40 is known to shear to a 30 weight in a short time. It's not a very stable oil when oil change intervals are extended. I don't know of any 0w-40 that will hold up as well as an oil with the spread of a 5w-40 or less. In your climate you will see little if any difference between 0w-40 and 5w-40. I am running the Mobil 1 5w-40 (aka Delvac 1) in the XJ right now, and I have to say my initial impression is that the Amsoil AFL 5w-40 is a superior oil based on engine noise and oil pressure. My ~10k mile UOA on the AFL in the XJ is here. The Suby has AFL in it right now and it sounds great. The suby has shown to prefer a 12cSt+ oil as far as piston slap is concerned. The average 30 weight is in the 10cSt range. Mobil 1 is a group IV oil, polyalphaolefin, as is Amsoil. Virtually all other oils (in the USA at least) that say they are synthetic are actually a group III, or a hydrocracked petroleum. Yes, what a scam, I know. Redline, Royal Purple, Esso, and Castrol 0w-30 are some other true synthetics. The reason I discourage group III's is because they cost nearly as much as a group IV, why pay almost as much for an inferior product. If I were you I would use German Castrol Syntec 0w-30 (my winter oil), Mobil 1 5w-40, Amsoil ATM 10w-30, Amsoil AFL 5w-40, or Rotella T 5w-40 (reasonably priced group III HDEO). Quote Link to comment Share on other sites More sharing options...
Setright Posted April 4, 2005 Share Posted April 4, 2005 Mobil 1 0W-40 is a very good oil! What's this talk about it shearing? Porsche, Mercedes, and the tuner AMG recommend this oil. Most are on a 15,000km interval. Which is quite reasonable. However, as has been mentioned above, why go for a 0W oil in your climate Axxiom? M1 5W-40, 5W-50, or possibly 15W-50 would probably serve you very well. Quote Link to comment Share on other sites More sharing options...
99obw Posted April 4, 2005 Share Posted April 4, 2005 Here are links to the first three threads I found when searching for "mobil 0w-40 shear". Shearing of this oil to a 30 weight is relatively common. http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=3;t=002332 http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=3;t=002106 5th response... "And notice that 40 wt. sheared back to a 30 wt. anyway. I think that 0W-40 Mobil 1 is the worst of Mobil 1's oils. I'd never use it." http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=3;t=001925 1st response... "The oil sheared to about 12.3cSt, but we expect this, I guess" I'm not saying that this is a bad oil, it shows good wear results, but if you want a 40 weight over the life of the oil this is probably a bad choice. If you leave the Mobil 0w-40 in long enough it will thicken back up to a 40 weight if that makes you feel better. If true 0w starting characteristics are desired I think a good group IV 0w-30 like German Castrol 0w-30 or Esso XD3 Extra 0w-30 is a better choice. These oils are a bit hard to find. The jury is still out on the American made Castrol 0w-30. Quote Link to comment Share on other sites More sharing options...
Tiny Clark Posted April 4, 2005 Share Posted April 4, 2005 All three of these look like they are from the same source, BOB. I take BOB and everyone else with a grain of kosher salt. I've had many cars over the years, never submitted my oil for analysis (although I could probably have our fuels folks do a spectrum check on it for free) and always had over 100k miles on them, still running like the day I bought them. My suggestion: stick with Mobil 1, use the weight appropriate for your local temps, change it regularly, and leave your worries in the rear view mirror. That is my 2 Euro-cents worth. Quote Link to comment Share on other sites More sharing options...
99obw Posted April 4, 2005 Share Posted April 4, 2005 I like kosher salt too. What's great about used oil analysis is that to a certain extent it takes the opinion and guesswork out of things. It's hard to say that the lab equipment that tested the oil is biased and full of baloney. cSt = centiStokes SUS = Saybolt Universal Seconds Mobil 1 0w-40 starts at 14.3cSt, or about 75 SUS. The SAE 30 weight range runs from 9.30-12.49cSt. The SAE 40 weight range runs from 12.50-16.29cSt. Clearly the oil has thinned in these cases to a 30 weight. The UOA links I provided had the following 100°C viscosities respectively: 64.1 SUS or 11.5cSt after 4650 miles 64.5 SUS or 11.6cSt after 3996 miles 67.4 SUS or 12.4cSt after 6120 miles This amount of thinning is alarming IMHO considering the relatively short intervals over which this oil was run in these engines. Don't get the impression that I am trying to pick on Mobil 1, as I am currently running the 5w-40. Mobil 1 is not the only company with viscosity issues, Amsoil 0w-30 and 5w-30 have been known to thicken in an alarming way. http://neptune.spacebears.com/cars/stories/amsoil.html I am not a lubrication engineer nor do I play one on TV, nor did I stay at a Holiday Inn Express last night. Quote Link to comment Share on other sites More sharing options...
Setright Posted April 4, 2005 Share Posted April 4, 2005 99obw, I don't think anyone here is offended. Just a sober discussion. Now, I did not read all three in detail, but I did notice that one car was an Audi S4. This has a high performance engine which could be running a slightly rich mixture and cause fuel dilution of the oil. I know the UOA has a low value for this parameter, but gas is volatile stuff and a large amount may have evapourated before testing. Hmm, 2001 S4? Isn't that twin-turbo? Could be that the driver has been cooking his oil by shutting off the engine after a hot run. Just hopeless guessing I know, but for me there are too many unknown factors that may have contributed to the oil thinning. Quote Link to comment Share on other sites More sharing options...
slo5oh Posted April 4, 2005 Share Posted April 4, 2005 Cookie (see my other post Synthetic Motor Oil wt question) I ran 0-30 wt for 10k on my '98 and I had no piston slap. I forgot to mention this in my other message... off to edit in a sec. I only ran it because I found it at wallyworld for $1 each. $1/qt for full synthetic is one of those offers I could not pass up so I bought all of them... (about 20)... It was somewhere between 80k and 100k at the time.... probably the entire 20k... but I can't recall. If it has always had synthetic you should not have the seal issue and maybe you might pick up a tiny bit of mileage. Let us know how yours acts on it regarding piston slap (louder, quieter, don't have it), and how it affects fuel mileage. Quote Link to comment Share on other sites More sharing options...
cookie Posted April 4, 2005 Share Posted April 4, 2005 These folks talking about viscosity change reminds me that the one thing my oil analasis on my BMW has consistantly showed is that the BMW semi synth was thickening to a heavier viscosity. (I believe it is Castrol). As the Blackstone lab guy said, "its common and I'm not worried about it". Quote Link to comment Share on other sites More sharing options...
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