Petroleum or Synthetic oil for my pickup truck?

f350_or_bustf350_or_bust Member Posts: 13
edited March 2014 in Ford
Wanted to start another discussion based soley
upon application of this question on trucks.

What is the general "rule of thumb" when it comes
to chosing when to, or not to switch to synthetic
based oils?

Does going to a synthetic oil change the need for
a higher or lower weight oil?

What brands do you recommend?

Thanks!!!!
«1345

Comments

  • themacguythemacguy Member Posts: 417
    Rule of thumb - whenever, though sooner is better. I've started out with it & changed Porsches to it at well over a 100k miles. Never smoked, seized or did anything but make the mpg's better and engines run cooler.

    Viscosity - a 10W30 synthetic is about the same as a 10W40 'normal' petro based product. Either is the choice for Texas (temperature) driving. A 5W30 maybe in colder climes. DO NOT use the 15 or 20W50 weight synthetics unless you tow heavy loads every day in high ambient air temps. or race the truck exclusively, and DO NOT use the new 0W30 anywhere except on permafrost. The viscosity doesn't 'break down' in synthetics as it does (at about 2,500 miles) in a petro based oil. But, most synthetics have some petro base in them along with the normal additives you get in the petro based oils. They (synths) can run longer however, if you require that - Porsche says normal is 10 - 15k. Pretty amazing.

    Brands - Mobil1, Amsoil, Castrol Syntec, Redline Pennzoil and Quaker State to name but a few. Also, look into the Mobil1 'style' filters. And change it sooner than marketing suggests: change it at normal intervals. I use Mobil1 synthetic in my new Dakota quad cab as it's readily available, and I literally run the crap out of it with nary a worry. I also run it in my 71 Chevy Super Cheyenne 400, Lincoln Towncar and various and sundry Porsches and 2 Volvo Turbos I own. I DO NOT run them in my bikes as they don't work really well with the wet clutches, though a couple of my friends do with good results so far (they say). Good luck. :-)
  • bookittybookitty Member Posts: 1,303
    f350, you have just heard from "the man". themacguy is an excellent source for many and sundry things, but when it comes to petroleum, lubricants (natural or synthetic); You can take whatever he says "to the bank".

    Bookitty
  • themacguythemacguy Member Posts: 417
    I'm not a 'rich guy' or anything. I just like cars, trucks and bikes. The Dakota is the first new vehicle I've been able to afford in 11 years (seriously, I've saved for a decade for this new truck). I just never can quite let go of the cars I've owned. The neat thing is the synthetics keep em running nice and smooth, and I REALLY want to keep this one for a long, long time. Hope-u-do-too!

    bookitty - thanks for the plug, but I'm still not sold on that 'cat' story.
  • bookittybookitty Member Posts: 1,303
    Jack, I thought you were rich. The big Texas "oil mogul."

    Further, to re-instill your confidence and faith in me, my cat is synthetic; Prior nomenclature was
    Sheltie.

    Bookitty
  • markbuckmarkbuck Member Posts: 1,021
    Three questions.

    What kinda bikes you got?

    If'in I wanna buy an 928S4, what should I look for and what should I skip.

    I can't remember what temp the SAE specifies for the xW viscosity testing and what temp SAE specifies for the -xx rating in the xW-xx oil weights.

    Oh ya, no problems with synthetics in any of my wet clutch race bikes....
  • arkie6arkie6 Member Posts: 198
    I have been running Mobil 1 15W50 in my 84 Honda CB700SC for several years with nary a problem. I also run Mobil 1 10W30 in my 84 Toyota Supra with 200,000 miles (rebuilt at 180,000 and switched to synthetic at 183,000). It uses and leaks no oil and seems to run better every day. I also extended my oil change interval from 3000 to 6000. I'm planning on changing to Mobil 1 5W30 in my Tundra 4.7L V8 at 6000 miles. I'm sold on it. It may cost a little more in the long run, but the feeling of using the best is worth something, plus, I do my own oil changes and with the extended drain intervals it does save me some time especially with all of the engines that I have to deal with (1 truck, 1 car, 1 motorcycle, 1 4-wheeler, and 1 tractor).
  • themacguythemacguy Member Posts: 417
    markbuck - mainly, [non-permissible content removed] multis: a 79 KZ1000 MK II, 80 Yam XS11 Midnight Special, 81 Yam XS11 M/S, 81 XS850 M/S, 81 XS11 Special (red), 79 Goldwing, 84 Yam XVZ12 Venture, 85 V-Max, 82 CBX, 83 650 Silverwing, 83 Honda 650 turbo, 86 BMW K100RT and a Suzuki RV125. All under 10k miles and near mint.

    928S4 - of course a good Euro 928S (1984 & 85 are best) is about the same performance - valves won't collide with pistons on the old 2-valvers if the timing belt fails. I'd say on the S4's "one that is not UNDER priced and has PERFECT books/records, in the 40-50k mile range." Also, they got better until the model run ended & 5 speeds are HIGHLY desirable (rare), though I prefer the Mercedes (sourced) 4-spd autos. Also, over a 100k miles and the aluminum frames / bodies start to fail at several % per year. Loses some stiffness. I still auto-x mine & never noticed the stiffness thing. Maintenance soars on these Porsches, though they're probably "THE best Sports / GT value ever, for the price you can get them for NOW." Performance is mind numbing. I've had a couple of 'locals' wet their pants in the passenger seats of both of mine - good thing they have leather (with synthetic sheepskin covers).
    They run like a ZR1 Vette without the drama at the 10/10ths level, but I'd say a good used ZR1 and / or the newer Camaro LT-1 version is a better all around deal. And the ZR1 will be worth a LOT more later on. Shoot it already is. The 928 was misunderstood by everyone except the auto press and people (like me) who believe front engine / rear drive/ water cooled sportscars are simply better. Porsche 'purists' killed it (and the 944 which quite literally SAVED the Porsche name from extinction as a privately owned marque).

    temps - only thing I remember vividly is the xW-xx thing / eg - a 20W50 oil needs (because of the 50 high end) a MINIMAL temp of something like 220-225 degrees F. Meaning it needs to be run in 'racing like' conditions; preheated & so on is best - but not absolutely mandatory - as it needs to get to operating temp quickly. I know dry-sump oiling is useful here as well. I do know the new 0W-xx is rated for Arctic Circle and similar cold climes only. I have a chart somewhere, I'll dig it up and post here as soon as I find it...

    arkie6 and markbuck - a guy I know (more toys than ANYONE I know of) who has a 1980 XS11 Midnight Special has been using 15W50 Mobil 1 in his since new, and everything else he owns - zero problems to date. He keeps telling me to switch, I just keep getting told about the synthetics 'short comings' in regards to the wet-clutch thing by some really good (at least they're well meaning) motorcycle race mechanics. In my racing kart, synthetics are precluded from use by the manufacturer and our racing organization due to 'dangerous conditions possible if used at sustained high rpm's of 10,000 and above.' My Yamaha K-100 runs at 12,000 so I don't use synthetics in the clutch. The Briggs class does allow it however, but they run about 4-5k rpm or so, and generally run dry clutches - the synthetics are used in the bottom ends of the 4 stroke Briggs vs. the oil burner 2 stroke Yams.

    BTW - F350 guy, my dad has run 2 million vehicle miles in his 77 years. He has never had even a MINOR engine problem; only had one ticket in his whole life and 20 or so vehicles, including a big GMC FWD motorhome and several hot rods and very neat cars over the years (56 Nomad V-8, 64 Park Lane w/ Interceptor engine, 71 Super Cheyenne w/400 V-8, etc.), and he was reluctant to even switch to a multi-vis oil back in the early 70's (or even a detergent oil!). He wouldn't know a synthetic if he wore it. The kicker: He's one of the best of the best petroleum geologists of all time - has forgotten more than most people will ever know about oil (not synthetics). Lives & breathes it. Has been responsible for more than 4,000 (thousand) drilled wells in the U.S. over a period of 45 years. He ought to know oil; makes you 'wonder' about synthetics. His secret? He changes his oil at 3k intervals, keeps the breathers & filters changed, doesn't 'lug' or hot rod the engine, cleans & 'rods' the radiators on a 2 to 3 year basis and keeps the oil & coolant full at all times. Must be doing something right. Or darned lucky.

    arkie6 - are you planning on using a Mobil 1 type filter? They are really nice, especially during cold starts and only $10. Oh, and how hard do you run your CB? Idle to warm up, ride slow or fast to get temp up, etc.? When (mileage) did you switch the oil to Mobil 1 on the bike?
  • wight1wight1 Member Posts: 218
    In reading through all the posts on synthetic oils, it seems as if everybody who is using them swears by Mobil 1.

    While this is undoubtedly one of the best synthetics out there, I've always been a Valvoline guy. I've used Valvoline conventional oils all my life with extremely good results. I've driven all of my vehicles well over 100K miles and some as much as 200K. With my new Silverado 3/4 ton though, I'll be doing a lot more towing with a heavier trailer so I've decided to go synthetic in this truck.

    Anybody have an opinion, real test data or real world useage indicating whether Valvoline's SynPower synthetic is as good as Mobil 1? Either brand is readily available to me in my local parts stores and the price is about the same (within 5 cents a quart), so that's not an issue.
  • mgdvhmanmgdvhman Member Posts: 4,157
    is not actually the best....but by farr the most popular..affordable...and most readily available..

    I run M1 5-30 year round in my 2500 Silverado.
    - Tim
  • wight1wight1 Member Posts: 218
    macguy,
    I just read some info last night on Royal Purple and looked at their website this morning - it really does sound like a good product, and its apparently available at most NAPA stores.

    Tim,
    I agree that Mobil 1 is the most popular and available, but if its not the best one out there,
    which do you think is?

    How do you like your 2500? any problems with it? I really am enjoying mine.
  • mgdvhmanmgdvhman Member Posts: 4,157
    as mentioned before...i will never go back to a 1500...even if I never haul another load again...but I don't see that happening any time soon..

    Well...I think Mobil 1 will keep up with the others...say...up to 10K miles....after that products like Amsoil and red Line seem to be better? I'd have to say Amsoil's 25K change interval that GM backs is pretty impressive.

    There is a local dealer for Amsoil right here...so it's not hard to get....I still chose Mobil 1....if for some reason I was wherever...and didn't have my extra bottle in the back...and needed it....I know I can get it a number of places.

    As I've said before...no way am I leaving oil in for 25,000 miles....no matter what anyone says. My oil light came on at about 4300 miles...and I have gone 1000 past that...so about 5-6K with Mobil 1 and GM filters are just right for me.

    Good Luck

    - Tim
  • wight1wight1 Member Posts: 218
    At what time did you change from conventional oil to synthetic - at first oil change, 2nd, 3rd? How many miles when you switched? I'm just curious since there seems to be big differences in opinion about "break-in" miles before switching. I'm still on conventional oil at 3600 miles on the clock, but will probably go synthetic at the 6000 mile mark.

    And no, I'm not trying to start that debate up again!!
  • mgdvhmanmgdvhman Member Posts: 4,157
    to be the rules...but here is what I did..

    600 or so miles.....changed initial oil to Mobil 10-30..

    about 2900-3400 miles.??...(can't remember)...changed to Mobil 1 5-30

    Had that in since...

    changed about 5-6 K miles with a Delco filter..

    I figure dealer sells Mobil 1....and if it's their filter...they can't say it caused a problem..

    - Tim
  • obyoneobyone Member Posts: 7,841
    last time I saw it at Napa at $6.98 a quart...I had posted a question in the Silverado topic if anyone had experience with this product as two mechanics that I know swear by it. Was planning on using it but did not have 10-30w in stock.
  • obyoneobyone Member Posts: 7,841
    bought a case...now if only I had a truck to put it in...
  • mgdvhmanmgdvhman Member Posts: 4,157
    5-30.

    Up to you

    - Tim
  • obyoneobyone Member Posts: 7,841
    only thing can't find it in Royal Purple and the coldest temperature the truck sees is 60-62 (very rare)mostly low 70's to high of mid 90's. Figure 5w or 10w wouldn't matter much at such mild temps.
  • mgdvhmanmgdvhman Member Posts: 4,157
    the fastest flow I can get at start up....even in the 70-90 degree summer here....The better off I am.
    ..without going to 0-30...I don't think GM approves that

    - Tim
  • z71billz71bill Member Posts: 1,986
    Is recommended in the Silverado (1/2 ton) owners manual if the temp is below zero.
  • markbuckmarkbuck Member Posts: 1,021
    z71bill is correct, my '99 1/2 ton documentation says consider 0W-30 if below 0.

    I run 10-30 in summer, 5w-30 winter and 0w-30 in the real winter.

    Remember folks that the xW rating is the viscosity at a particular temp (guessing 32F) and the -xx rating is in at a particular temp (guessing 200F or 212F or 225F) The VI's in most multivis conventional oils tend to lose their effectiveness above and below these two sorta arbitrary setpoints, thus the value of either blended or full synthetics or even straight weight oils.

    Anybody out there remember the actual temperature the viscosity is tested at....
  • mgdvhmanmgdvhman Member Posts: 4,157
    of pure heaven so farr...
  • tubeking1tubeking1 Member Posts: 6
    Carefull what you buy in the synthetics arena, this tiny but highly profitable portion of the market is full of baloney vendors. Some synthetics barley meet the legal definiton. Not they they would likley damage your motor, just that your getting zero gain from their 3x price. IMO.
  • bmaigebmaige Member Posts: 140
    I have several auto parts houses here in town that take used motor oil. Is there any problem disposing of synthetic, or do these same auto parts houses not care which you have and accept everything you take them--petroleum or synthetic? I would think, if synthetic doesn't break down, the manufacturers might want to recycle it themselves.
  • amoraamora Member Posts: 204
    read "The surprising truth about motor oils" on internet. this independant company tested over 60
    taxis in NYC and put all brands, Mobil 1, pennzoil, castrol, etc in 5W-30 - 10W-30 weights,
    changing oil at 3,000, 6,000 and 12,000 under the
    most severe driving conditions.
    According to report there was no difference in
    performance between the $4.50 a qt. stuff vs the
    .89 cents a qt. oil. all oils used had the Starburst symbol and were API SJ rated. No
    significant difference between 3,000 and 6,000 mile change interval on engine parts. at 12,000
    mi a very slight difference. ha ha ha!! Oil companies are laughing all the way to the bank with our gullability in changing oil every 3,000
    mi. All the API SJ rated oils from all the makers
    performed equally well, regardless if they were
    synthetic or mineral based. If it makes you feel any better, use the synthetic. It is all there,
    on the internet, see for yourselves. regarding
    the additives, FORGET ABOUT IT...am going to
    change my oil in my '00 chevy 2500 5.7L at
    5,000 mi intervals with 10W-30 ProLINE available
    at PEPBOYS for less than a buck and run my
    Chevy beyond 300,000 mi like my dad did in his '74
    using straight 30W Pennzoil........
  • jmendojmendo Member Posts: 13
    Castrol Syntec 10w-30, the best synthetic oil, that's what I use
  • davids1davids1 Member Posts: 411
    How many cold (single digits or below) did they perform. That's the main reason I use synthetic.
  • amoraamora Member Posts: 204
    Hmmmm....Pennzoil just spent 250 million improving their so called crappy oils. Pennzoil synthetic
    w/PENNZANE is around $4.49/qt. Pennzoil says to change every 3000 mi if driving in severe conditions. They said they developed the stuff
    for use in outer space....WOW!! It is more expensive than Mobil 1. I think I will try
    ProLINE Silver semi-synthetic 5W-30 API SJ for
    about .89/qt. for my first oil change. I now have
    1200 mi on new '00 C2500. Will think on it some more as I rack up the miles on my 78 mi one way
    commute 2.5 times a week. (CARPOOLER).
  • erherh Member Posts: 7
    oil and oil change interval stuff. I have a '91 Nissan p/u with 4 cyl. I've used all sorts of different oils in it: Castrol, Pennzoil, Mobil, Quaker State, the cheap Wal-Mart store brand. Have used 5W, or 10W. I've used petroleum based and synthetic. I've changed oil as frequently as 5,000 miles and gone way over 20,000 miles between changes at other times. The truck now has 195,000 mi. on it with no signs of quitting any time soon.
  • markbuckmarkbuck Member Posts: 1,021
    This guy knows his stuff. His name is MWICKLE. Chem engineer working on oils.





    START>>>>>>
    Could not resist jumping in on a few
    misconceptions in the thread.

    First...ash content has nothing directly to do
    with sludge...ash is simply a measure of the
    inorganic metallic compounds "left over" when the
    orgainc stuff is burned away. Typically this is
    Zinc Dithiophosphate (spell?) in PCMO (pass car
    motor oil). Comparing this as a basis to purchase
    oil is not a useful measurement, only really useful
    purchase specs is GF-2/SJ spec (or similar
    BMW/Euro approvals) & weight/vis. Ash is sometime
    relevant for engines sensitive to valve deposits
    from oil in some types of engines (not cars & light
    trucks).

    Second...syn typically only "lasts" longer if it
    has more better/additives in the original
    formulation than other comparable non-syn oils(and
    a good filter)...the syn base oil itself is no more
    likely to "break down" than most mineral-based
    oils. In fact, some hydrogen-treated, catalytically
    dewaxed conventional oils (called "Group II" in
    trade) perform in most respects like syn .I believe
    from Marketing messages, but do not know factually
    (trade secret formulas), that some premium syns do
    probably have above-spec./next-generation "type"
    premuim additives providing more "safety margin" if
    you will.

    Syn IS less likely to sludge-up if you have high
    temp zones in engine like 'vettes, turbo's. Also
    lubes faster at start-up in cold places w/o engine
    heaters. Some technical researchers say it has less
    internal friction (due to uniform molecules) and
    gets better mileage; some say this is mostly
    viscosity effect (blend to lower viscosity in
    acceptable range for the grade always gets more
    mileage mileage), and in any case no consumer will
    likley be able to measure a statistically
    significant change of only 1% or so in milage
    (odometers, pumps, gas blends, and driving
    conditions vary WAY WAY too much from tank to tank
    to reliably measure small mileage differences.

    Dirty oil says NOTHING about how much useful life
    the oil has (was true dirty=bad when oils had no
    additives in them befor about 1960 or so). Only
    tests can tell when an oil is worn out.

    Here is some stuff I put in another group on oils
    & oil condition tests:

    There are some rather interesting opinions on
    oils/lubrication/testing/extended drains...then
    again cars can be a passion for enthusiasts.

    At work, we use Cleveland Tech (CTC) for used oil
    analysis, they may do some OEM-branded tests too,
    I dunno. But our work is for fleets, and mostly
    HDMO (i.e. sooty diesel engines, not PCMO-Pass Car
    Motor Oil).

    I NEVER recommend **consumers** vary from OEM
    drain and viscosity reccommendations no matter
    what
    testing processes they do...risk/reward is too
    small IMHO. It is fine to be more conservative,
    and/or test, but sent max. intervals at OEM
    limits. Very surprising the amount of 10W40 & 20W50
    PCMO we sell...BUT no OEM recommends those grades
    any longer (and has not for a while). Old
    habits/beliefs die hard.

    For the record, I use syn & premium (or OEM)
    filter in my personal car and change at about 5K
    miles...this is overkill, but heck oil is
    cheap...engines are not. The syn does not lube
    "better", but does provide some additional safety
    margins in some areas. I have used oil analysis
    from time to time on my older car to check
    conditions. Titan Labs (sold at K-mart) has a
    consumer-friendly report. Most folks should avoid
    purely numeric reports like fleets use.

    My PCMO oil advice to consumers is mostly like
    "Click & Clack"(NPR car show) give:(1) GF2/SJ oils
    are very good even at base spec. blend (2) buy a
    major brand (big oil co. or retail brand---the
    issue is day to day quality control, NOT who is
    "best"...around 5% if I recall correctly, per API
    and State of NC (only state that checks) are
    misblended/sold off-spec (3) change and use a good
    filter each time and do it at *5000 miles* not 3000
    oil change places say...when the color get darker
    the oil is still fine for service. If you are TRULY
    severe service (per OEM), then do that
    recommendation for miles (4) Add nothing to the
    oil...it is a competitive market if their was a
    miracle additive in would be in oil in the first
    place...our developers are pretty smart
    formulators, and I think know a lot more about
    engines than most infomercial people.

    Disclaimer: most oil manufactures say follow OEM
    recommendations...too many Lawyers out there to
    vary from that advice if you are a big deep pockets
    company...little oil supplers can vary and push
    extended drains...I think they need a way to
    merchandise oils, and it is quite true that done
    right extended drains are possible (look at newer
    Mercedes & BMWs).

    FWIW, I do have a professional basis to comment on
    oils, relevant credentials (besides employment:
    lubricants technical training at major oil co.)
    are ChE degree, and STLE (Society of Tribologists
    and Lubrication Engineers) CLS(tm) credential
    (Certified Lubrication Specialist). Waaaaaay too
    many posters in these technical forums sound too
    "authoritative" in their tone. Claiming a
    cause/effect relationship (or implying it) without
    data is silly...Like race car *drivers* endorsing
    oil additive...come on, that is "testimonial" not
    proof/solid evidence. Netizens beware...
  • 19delta19delta Member Posts: 4
    What type of synthetic oil do you use, and why? All sybthetics are not the same and many are not true synthetics at all.
  • himplomhimplom Member Posts: 3
    I took organic chemistry about 30+ years ago and my professor was a petroleum chemist and synthetic oils were just being developed. One thing we found was that synthetic oils seemed to have better adherence to metal parts than petroleum (paraffin)based oils; as such we thought this was a great property as the metal engine parts would have continuous lubrication. This was supposed to translate into superior wear characteristics. Also we found that the molecular properties of synthetics were better in shear strength meaning they would not break down as readily as petroleum oils. What I am seeing in this topic discussion seems to contradict our old theories. So the basic question is: are synthetics really worth the difference in cost?
  • chadc777chadc777 Member Posts: 54
    I have used synthetic in my vehicles for the last 6 years or so. What convince me? I changed from 5w-30 pet. to 5w-50 syn. (Castrol Syntec) and my gas mileage improved 2-3 mpg (in the winter time). Most of that improvement was likely realized at cold startup times since my long trip mileage didn't really increase. The extra gas mileage paid for the increase in oil cost AND then some. So I actually saved money by switching to an oil that cost 3 times as much. Again, the mileage increase was mainly in the wintertime, but that tells me there is a benefit year round on cold enngine startups. Good enough for me.
  • z71billz71bill Member Posts: 1,986
    Why use 5w50 oil - is your every day driver an Indy race car?
  • chadc777chadc777 Member Posts: 54
    Why not use 5w-50? It flows the same as 5w-30 yet protects better. Besides, when I switched to Castrol Syntec years ago, it's the only weight it came in. I was a little curious why they ever came out with the 5w-30. I guess for people that were scared of the 50 number in 5w-50 and didn't realize it flowed just like the 5w-30.
  • z71billz71bill Member Posts: 1,986
    You should do some research on oil - maybe start with your owners manual. If 5w50 "protects" better than 5w30 why don't all the manufacturers call for its use?

    If I had a high mileage (100,000 +) engine that was using a quart of oil every 1,000 miles I would use ?w50 oil - at that point in the engines life who cares - but for a low mileage engine that is running right, not using oil it would be foolish -IMO. If you do the research you will find that 5w50 oil will give you less mpg than 5w30, and in fact be harder on the engine in terms of wear.

    Not trying to give you a hard time - it's your engine - so do whatever you want. I have read many articles on oil, been to a few classes on lubrication of industrial motors -not that I claim to be an expert -but everything I have learned is opposite to what you are saying.
  • chadc777chadc777 Member Posts: 54
    The drivers manual is for the everyday person that is not willing to by synthetic motoroil anyway so why would they put it in there? Besides, even though most manuals say to use only 5w30, the dealerships service departments still buy bulk 10w30 and put it in everything that comes their way. Why? I don't know. Many say "It's all the same" though that obviously is not true.

    I didn't claim to be a lubrication wizard so I am always willing to learn more details. In fact I love them but I have never had a chance to dive more deeply into this subject. No time like the present. I was always led to believe that in the multiviscosity oils, the first number was the "flows like" number and the second was the "protects like" weight. Maybe you can help clear this up then. Obviously a 20w50 flows better than straight 50 and 10w40 and 5w30 flow better than their respective straight weight (40 and 30 respectively).

    So 5w30 and 5w50 do not flow the same? Using that logic, does 10w30 flows better than 5w50? I would think the 5w50 would flow better than 10w30. What about comparing the 0w30 with 5w30. They flow the same since they are both 30 weight or does the 0w flow better than the 5w?

    Maybe the difference is in operating temperature and that is what I'm missing. Is that the key to all this? I believe the 'w' weight is at outside temperature before engine operating temp is reached. Is the second number meaningless until we are at operating temps? Just trying to understand.
    Are you saying that 5w50 flows, once at operating temperature flows not better than 20w50 or straight 50 weight?

    By the way, this is all regarding synthetics, not conventional oils, though I'm sure this applies their, too. All I know is when I switched from 5w30 conventional to the 5w50 synthetic in one of my vehicles years ago, mileage improved significantly in the winter time and a smaller amount in the summer. If I go from 5w50 syn. a 5w30 syn. should my mileage increase again or be about the same? As I said in my previous post, the 5w50 weight was all that was available in Castrol Synten when I decided to try it back then and I guess I never really thought I should switch when the 5w30 came out. I thought the 5w50 would be better. Guess it's not from what you are saying.

    What is it about a 5w50 syn oil that makes it harder on an engine that a 5w30? I realize why a 20w50 would be harder on a day to day engine as would straight 50. It would take way longer for the oil to start freely flowing so less oil protecting the engine until it warms up. But when comparing 5w50 and 5w30, what makes the 5w50 harder on my engine?

    (I may not be able to check back for a couple days as I am going out of town for the holidays but will try. I really am interested to find out exactly how these numbers effect real world daily drivers).
    Thank in advace for any more insight you can provide.
    Chad




    As I said, I started using 5w-50 when it was the only variety Castrol Syntec.
  • z71billz71bill Member Posts: 1,986
    You are basicly correct. The 5 in 5w30 means when engine is cold it flows like 5 weight oil. I am old enough to remember when you could buy straight 5 weight oil (also 10, 15, 20, 30 and 40) people up North would use the light weight stuff when the temps were below 0. The second number 30 in 10w30 is the weight of the oil after your engine warms up to normal operating temps. So 5w50 oil starts out like 5 weight and ends up 50 weight. In one class I took an old engineer explained it like this: If you were running down the beach on a very hot day you would have 3 choices. 1. Run up on the hot dry sand, 2. Run in water up to your knees or 3. run in the wet sand right at the waters edge. Which is easier? He compared the hot dry sand to a very light weight oil, the deep water as a very heavy weight oil and the wet sand as the right weight oil. To use his example using 50 weight oil would be like running in deep water. I hate to admit this but this example is the only specific thing I recall from his class.
  • chadc777chadc777 Member Posts: 54
    Gotcha.

    So, at operating temperatures, 5w50, 20w50, and 50 all flow/act the same. 10w30, 5w30, and 0w30, and 30 all flow/act the same.

    At startup, 5w30, 5w20, 5w40, 5w50, and 5 all flow the same. 10w30, 10w40, and 10 all flow the same. I guess 0w30 flows like air! Seriously, though, if 0w30 flows the best on startup yet protects like any other 30 weight like 5w30 and 10w30, shouldn't 0w30 be the best whether you are in 40 below, 40 above, or 80 degree weather?

    Even 80 degrees outside is a far cry from normal engine operating temperatures so wouldn't the 0w30 then hold the advantage over all others to get 'oil to the vitals' faster and better? My last oil change I switched to Mobil 1 5w30 and now am wondering if the 0w30 would be a better choice. If both are 30 weight at operating temp but one flows better and quicker at starting temperature (the 0w30), shouldn't everyone (whose engine calls for 30 weight) use that? What do you think?
  • z71billz71bill Member Posts: 1,986
    Your logic seems correct to me. My 99 Silverado owners manual says to use 0w30 if temp is sub zero. I also noticed in one of your prior posts - that most dealers use 10w30. I have run into this problem with 3 different service departments. They all put in bulk oil systems back when 10w30 was the standard, now they are to cheap to put in an additional tank. I bought a book of 10 oil changes for $75 when my 98 Tahoe was new. They gave me all kinds of crap because I demanded 5w30 per the owners manual. The service manager told me the 1 quart bottles of GM oil in 5w30 cost them $1.50 per quart. 10 changes at 5 quarts each would cost them $75. I am down to my last coupon so looks like I will start to change it myself.
  • markbuckmarkbuck Member Posts: 1,021
    All engine oils thin when heated.

    A 10W-40 multi-viscosity oil will match a straight 10 weight's oil thickness (viscosity) at one specific cold temp (32F). This same multiviscosity oil will thin out less than a straight 10 weight oil as temperature rises. In fact, the multiviscosity's oil thickness' will be the same as a straight 40 weight oil at one warm temperature (200F).

    What happens above and below these two specific temps is not captured by the _W-__ SAE thickness measureing system. Synthetics almost always work better at both ends of the spectrum (more linear). Conventional oils are likely to thicken more than an equavalent synth oil at temps below the "_W" rating and thin more than than the synth above these temps.

    Additionally, and very important, the additives (called VI improvers) tend to break down with time so the less VI improvers one uses, the better. As the VI improvers break down, the oil reverts more and more to acting like the 5W-xx oil weight.

    The only thing I'm uncertain about is the exact temp used to measure viscosity for the low and high temps (I made up 32F and 200F).

    Hope this helps.
  • rrichf1rrichf1 Member Posts: 47
    It has been explained that oil viscosity changes with the temperature of the oil. The warmer the oil gets, the thinner the oil or the easier it flows. To create multigrade oils, viscosity enhancers are added to the base oil stock. The wider the range of the oil operating temperatures the more viscosity enhancers are needed. Remember that the oil's operating temperatures will always range from the lowest ambient temperature (Truck parked outside at night) to a fully warm engine. (About 200-220 degrees) If you oil's operating temperature is significantly above this range you are probably in some really deep used oats.

    There are several important things to consider when selecting the engine oil. You really need to use what the manufacture requires if you expect to keep your warranty valid. If the oil is too thick at normal operating temperatures your mileage will suffer. If the range of the oil's operating temperatures is wide, (i.e. 5w50) the oil contains more viscosity enchancers than an oil with a narrow range. (i.e. 10w30) There is an exception to the rule. If you regularly drive in an extreme climate it is acceptable to use a thinner oil to insure easy starting. Also the thinner oil provides better lubrication during cold engine start up. The thicker (a.k.a. Heavier) weights of oil are less likely to seep between the cylinder walls and rings and are used in higher mileage engines to compensate for normal wear. The heavier weights of oil flow more easily into the wider gaps around worn bearings. In a new engine it would not surprise me if a heavier oil actually increased bearing wear because the gaps are narrower and more difficult to be lubricated by the thicker oil.

    IMHO, While your vehicle is new it is unadvisable to exceed the vehicle manufacturers requirement for oil weights. If the recommendation is for xW40 oil, I would not use xW50 until the engine actually needed it to stop oil burning.

    Rich
  • erikheikererikheiker Member Posts: 230
    When my 89 GMC S-15 had 9k miles on it I started using Mobil 1 5W30. I also put in a quart of Slick 50 at that time. To date the truck has over 111k miles on it and I go 10k miles between oil changes without adding any oil. Since then I've learned several things. 1) I get the impression that the PTFE in Slick 50 can clog the oil filter and is not recommended by Mobil. 2) Apparently you can use Mobil 1 or any other synthetic right away. I have a new GMC Sierra and I plan on switching to Mobil 1 at 3k miles. I know that there are a lot of choices out there, but Mobil 1 has been recently reformulated and it is everywhere, so I'm sticking with it. But I think I'll pass on the Slick 50
  • erikheikererikheiker Member Posts: 230
    Anybody have any comments on the Fram Double Guard oil filters that have PTFE (Slick 50's teflon ingredient)? I used them a couple of times with my 89 GMC, but I have no idea if it had any effect. I'm tempted to use the Mobil 1 filter, but they are expensive and hard to find. OK, I know I shouldn't quibble over a few bucks when I'm trying to maximize the life of a $27.5k truck!
  • z71billz71bill Member Posts: 1,986
    I have read several places that Fram is the worst oil filter on the market. I just stick with the AC/PF 59. They are only $2.99 at Autozone. I change oil every 3,000 miles (which for me is about every 4 months) - this may be overkill, the oil life monitor goes off between 3,300-3,700 - I figure for the $10.00 it costs to change my oil it is money well spent. I also hate the look of dirty oil on my dipstick.
  • erikheikererikheiker Member Posts: 230
    It's amazing how much of an education one can get from this site. I have now determined that a Fram oil filter will never be used on my 2001 Sierra! I'll try finding a Mobil 1 to fit, but barring that, I'll use AC Delco or NAPA.
  • steve234steve234 Member Posts: 460
    The Fram filter that is considered low quality is the base model. The Double Guard and Tough Guard are better rated. One of the best is the Motorcraft filter.
    Slick 50 is a good product that has taken a lot of hits because of cheap imitators. Slick 50 developed a formula that used teflon as an additive, but chemical bonded. Several companies brought out products with teflon, but did not properly bind it and it separated from the other additives. The effect was like adding sand to the oil. The word got out about this and Slick 50 got branded by association.
    While I have always been a fan of Slick 50, with today's synthethic oils, I do not feel a strong desire to continue using it. STP is another good product that is less used today, because the oils got better.
  • erikheikererikheiker Member Posts: 230
    It's my understanding that even the Double Guard and Tough Guard filters have the cardboard end caps and the cheesy plastic valve. No more Frams for me!
  • z71billz71bill Member Posts: 1,986
    IMO both are a waste if you have an engine that is operating as it should. I have used Slick 50 - it did nothing - no improvement in MPG -did not quiet the lifter noise - who can tell if it did anything to prolong (another worthless product) engine life. STP lost several law suits back in the late 70's early 80's for making claims that it could not prove. It was a marketing supported scam. The racers edge. Good slogan - worthless product. It was just 80 weight oil, packaged in a cute can. Dump a can of this junk in your car in the winter and it does more damage that good.
  • steve234steve234 Member Posts: 460
    If you are expecting miracles like curing lifter noise from slick 50, then you are bound to be disappointed. These are not miracle cures for bad engines. STP was OK, but the additive packages standard today made it obsolete. Anyone who has used it and works on vehicles can tell you that it was not 80w oil. Slick 50 is like the synthetic oils. It normally will extend the life of the engine that uses it and may get better gas mileage. There are no absolutes because every engine/driver combo is different. With all the additives available, there are good products and bad. Personally, I would never use Marvel Mystery Oil for any reason, along with most of the other crap on the market. I have been privy to some testing done on Slick 50 and found that it was an acceptable cost/benefit a few years ago. If I was staying with dyno oil, I would still add it. I may not continue to use these products, but I also have no desire for a 286 or 68020 based computer. Time and technology moves on.
  • z71billz71bill Member Posts: 1,986
    It has been 20 years since I put a can of STP in an engine. My memory may be slipping. What I remember was a very thick oil - almost like honey - am I mixed up? What weight would you estimate it to be?
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