Reason01 Posted May 2, 2004 Share Posted May 2, 2004 I know this must have been discussed many times on here. I'm sure it will be discussed many time after too. My next oil change (next week) I'm going to use Mobil One synthetic oil. I hear that synthetic is thin compared to dyno. Should I move up to a 10w from a 5w just to make sure nothing leaks? Link to comment Share on other sites More sharing options...
mattocs Posted May 2, 2004 Share Posted May 2, 2004 I'd also go with synthetic but I have 92,000 miles on my car and don't know if I should start with that many miles. Link to comment Share on other sites More sharing options...
Setright Posted May 2, 2004 Share Posted May 2, 2004 Switch to synth at any mileage. Worn seals will leak. Not the oil's fault. Don't believe all the myths! Link to comment Share on other sites More sharing options...
frag Posted May 2, 2004 Share Posted May 2, 2004 Switched at 90,000 miles. No problems. Much easier starting when outside temp is very cold. Changing the oil myself costs me about the same price I would pay if I had it done at the shop with regular oil. Link to comment Share on other sites More sharing options...
99obw Posted May 2, 2004 Share Posted May 2, 2004 I think the fact that Mobil 1 is relatively thin may have given all synthetics a bad name. That's why I use Amsoil, much thicker. I actually think Mobil 1 is a little bit better oil, but too thin to use the proper grade in an engine with some miles on it IMHO. At least with Mobil 1, the kinematic viscosity of the 5w and 10w-30 are the same at operating temperature. Both 10cSt. 30 weight oil runs from 9.30-12.49cSt, so you can see that is on the thin side. The 5w has a higher viscosity index, giving it better cold temperature performance. Synthetic oils clean better, so if you put it in a really dirty engine with old seals you might see some new leaks. When synthetics were first introduced, leaking was a problem. Then the oil makers began adding additives to condition the seals, and now most major brands don't cause leaking problems. Link to comment Share on other sites More sharing options...
rweddy Posted May 2, 2004 Share Posted May 2, 2004 Switch to synth at any mileage. Worn seals will leak. Not the oil's fault. Don't believe all the myths! Yep could not agree more. I swiched at 110k and now getting 2 more miles per gallon. Stick with same weight, you will be fine. Link to comment Share on other sites More sharing options...
Setright Posted May 3, 2004 Share Posted May 3, 2004 Hmm, maybe I should start exporting Mobil 1....I run 5W-50. Not too thin, so vapour loss is not a problem. Why on earth don't they sell this visco in the states?? Link to comment Share on other sites More sharing options...
Reason01 Posted May 3, 2004 Author Share Posted May 3, 2004 So I should stick with the same weight? Link to comment Share on other sites More sharing options...
rweddy Posted May 3, 2004 Share Posted May 3, 2004 I am running 10-30 in mine w/no issues in my 91 with 114k. I have switched many vehicles with high mileage and have had no issues except for one vehicle. A 80 CJ7 but that is another very long story!! Link to comment Share on other sites More sharing options...
Scoobaroo Posted May 3, 2004 Share Posted May 3, 2004 Mobile 1 10w 30 is a good all around weight oil unless you live in Siberia. I use it in my Toyota and Subaru with no problems. Change it every 5K and don't worry about it. An oil analysis will cost you as much as just going to Walmart and buying 4 brand new quarts. Alot of this oil analysis stuff has gotten out of hand. Mobile 1 is the best Synthetic ever (even though other snake oil salesmen will tell you different) and it's available almost anywhere. Link to comment Share on other sites More sharing options...
northguy Posted May 3, 2004 Share Posted May 3, 2004 PM Mcbrat. I believe he uses it in one of his higher mileage Brats with no problems. Link to comment Share on other sites More sharing options...
blitz Posted May 3, 2004 Share Posted May 3, 2004 Hmm, maybe I should start exporting Mobil 1....I run 5W-50. Not too thin, so vapour loss is not a problem. Why on earth don't they sell this visco in the states?? Good question. Castrol, Pennzoil, and Quaker State have all offered various 5W-50's in one form or another here in the states over the last 10 years or so but for some reason Mobil hasn't. The closest we get is the 0W-40 and the 5W-40 SUV. I currently run a 50/50 mix of M1 10W-30 & 15W-50 in the summer. I had tried all M1 10W-30 but I could hear a rod making noise at hot idle. Link to comment Share on other sites More sharing options...
mheilmann Posted May 3, 2004 Share Posted May 3, 2004 What about Valvoline synthetic? I'm considering the switch in my '97 legacy (115K). Are Valvoline/Mobile 1 the same? Comparable? I've used Valvoline 5W-30 dino up to now. Link to comment Share on other sites More sharing options...
99obw Posted May 3, 2004 Share Posted May 3, 2004 Mobile 1 is the best Synthetic ever (even though other snake oil salesmen will tell you different) and it's available almost anywhere. If Mobil 1 was so good it wouldn't need to be mixed with a thicker grade to run without increased engine noise. I quit running it because it made the engine sound like a bucket of bolts. Mobil 1 Xw-30 is a GOOD oil for newer engines that is way too thin for most engines with some miles on them. I would still be a Mobil 1 customer if this wasn't the case. I have found two of my engines with ~150k miles prefer a ~12cSt oil such as Pennzoil HM 10w-30 or Amsoil ATM 10w-30. Less engine noise and much lower consumption. The subaru drinks Mobil 1 at 10cSt. I do plan on switching to probably a 5w-40 at 200k miles. Say what you like about Amsoil. I agree that their marketing is very questionable. I think Amsoil would be a much more successful company if they would drop the pyramid scheme. PS: Fram filters are available everywhere too. Link to comment Share on other sites More sharing options...
blitz Posted May 4, 2004 Share Posted May 4, 2004 99, the interesting thing is that my M1 10W-30 noise was in a brand new engine (under 10k miles). Although not a scientific conclusion by any stretch of the imagination, I swear there's something different about PAO lube with regard to it's ability to damp mechanical noise (given a uniform viscosity for sake of comparison). PAO's just seem "drier" and more "rigid", whereas dinos & POE's seem to be "juicier" and "springier". There has to be some quantifyable property of oil which falls outside the standard newtonian measurements of "viscosity", "viscosity index", and "viscosity under sheer". Something in regard to the fluid having a particular natural resonant propery under excitation or something like that, and it would be related to a different molecular lattice structure. Link to comment Share on other sites More sharing options...
powderhound Posted May 4, 2004 Share Posted May 4, 2004 Currently running Mobil 1 5W-30 with 107,000+. I have used Mobil 1 since new and only change it twice a year...once in the fall and once in the spring. I use 0W-30 in the winter. Seals started leaking at 103K. IMO Mobil 1 is the best oil you can buy, synthetic or otherwise. Change it yourself and it costs the same as having a shop put in brand X crap...plus you get longer intervals...5k seems like a waste of money to me...I would say 25K...the only reason I change mine sooner is so I can get a better weight for the cold/hot weather. Link to comment Share on other sites More sharing options...
BlueTrain Posted May 5, 2004 Share Posted May 5, 2004 i'm not sure if i'd wait 25,000 between changes. at minimum, i'd at least swap out a new filter here and there to keep the oil relatively clean. Link to comment Share on other sites More sharing options...
wrxsubaru Posted May 5, 2004 Share Posted May 5, 2004 Swiched my dads legacy over to vavoline synthetic at 230,000 miles, no real problems, ecpet i had to replace the oil filler gasket. Link to comment Share on other sites More sharing options...
bratman2 Posted May 5, 2004 Share Posted May 5, 2004 Mattocks, switched my 87 Brat over to Mobile 1 at 140K, currentily have 189k with no problems or leaks. I use 10w-30 and had replaced front seal and rear seals years ago as preventive maintaince. Change it once a year which comes to about 8k, add 6-8ozs every 3k. Switched my daughter's 93 Legacy at 115k (bought it with 114k), change it every 10k adding app. 8ozs due to use every 3k, front seals were replaced with timing belt at 159k also as preventive maintaince. The 93 currentily has passed 165k the last time I saw it and has no leaks. Wife's 2003 legacy I change at 7.5k by the book with mobile 1 was using 5-30 with no engine noise but just changed it to 10-30 so I could just buy 5qt jugs of Mobile1 in one weight. I would be scared to go 25k without oil testing and as someone else stated the cost of that you might as well change it. 99 OBW, Mobile 1 being thin is not were the rumored oil seal leaks come from, when Mobile 1 was firsted marketed in the mid 70's it would cause seals to shrink and this was not a rumor as I used it in the seventies. This has been fixed by Mobile along time ago but rumors are much harder to fix. Mobile 1 being thinner can have advantages such as higher flow rate, slightily higher fuel economy ( probably really hard to measure that one), and better low temp starts. Amsoil weight for weight will most likely have the same advantages. I would not assume Valvoline synthetic is the same as Amsoil or Mobile 1 as it is legal to call hydrocracked conventional oil synthetic now thanks to Castrol. They are not the same period. The only advantage to synthetic oil might be if you planned to keep a vehicle till it expires, you wanted to extend the changes somewhat, wanted a good warm feeling inside( that's me), drove under harsh conditions ( super cold, heavy load, super hot, lots of idling). I would suggest doing a search for " spacebears synthetic oil test", very interesting reading. Link to comment Share on other sites More sharing options...
mattocs Posted May 5, 2004 Share Posted May 5, 2004 hrrm...I have 2,000 miles to go until my next change...i'll think about going synthetic. Can I still use the Purilalator filter or should I change to a different kind? Link to comment Share on other sites More sharing options...
Draco Posted May 5, 2004 Share Posted May 5, 2004 The Purilalator filter is a good filter and cheap too. Thats what I use in my '97 Legacy, Mobil1 5w30 and a purilator. Don't know who is thinking about the 25k oil changes but thats just rediculous. Doesn't matter how great the oil is after ~15k or so it is just going to be very dirty and it will hurt your engine. Link to comment Share on other sites More sharing options...
sparkster58 Posted May 6, 2004 Share Posted May 6, 2004 ok ok...ive had syn in my 87 DL for 3 yrs....i use quackerstate 4x4 blend/10-30 No runs,no burning,no smell.....clean as a whistle.... iam hitting 208k soon... sparkster:headbang: Link to comment Share on other sites More sharing options...
Reason01 Posted May 6, 2004 Author Share Posted May 6, 2004 So Mobil One is good then? I think a good oil filter would be K&N. I just got 1 and I will use it with the Mobil One oil this week. Link to comment Share on other sites More sharing options...
Scoobaroo Posted May 6, 2004 Share Posted May 6, 2004 Sorry if this is a repost, but here's an excellent article on Mobile 1. http://neptune.spacebears.com/cars/stories/mobil1.html#samples Interesting that engine wear actually DECREASES as oil ages meaning that it's a bad thing to change your Mobile 1 too frequently. Link to comment Share on other sites More sharing options...
powderhound Posted May 6, 2004 Share Posted May 6, 2004 Thank you scoobaroo. Very interesting. Like I said if I lived in a climate with little temp fluctuation I would have no worries about running Mobil 1 for 25k. The key is in the top off oil...it actually reduces the age of the oil. The last line in that article is very interesting. Read it. Link to comment Share on other sites More sharing options...
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