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Petroleum or Synthetic oil for my pickup truck?



  • 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.

  • 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
  • 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 Posts: 2,000
    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.
  • 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 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.
  • 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 Posts: 2,000
    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 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 Posts: 2,000
    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?
  • I remember when I was young and dumb instead of old and cheap; I added STP to my 67 Mustang. I think it said on the can to pour it into the engine while the motor was running. That fan blew all of that crap all over the engine compartment! It was FUBAR big time. Now that I'm old and cheap, if it don't need it, its not goin'in there.
  • steve234steve234 Posts: 460
    That is about the best discription. It was about that consistancy, but not slick like oil. I always poured it into a hot engine and then idled it for a few minutes. I used to race a 72 Comet and was always looking for more power and reliability. Had all the then current hot mods, dual exhaust with crossover pipe, flex fan, Offy 360 manifold and the first of the electronic ignitions, a Hayes Magnapulse. It took me three sets of plugs before I found out they had failed to include regapping the plugs from .032 to .045 in the instructions.
  • adc100adc100 Posts: 1,521
    You are throwing away good money and possibly harming your vehicle in the process by not having the proper viscosity. Probably also losing milage. Swith to synthetic oils. It's a no brainer. I use Mobil 1
  • wilcoxwilcox Posts: 584
    There's a word we don't see much these days. Are all motor oils high detergent unless the label says otherwise?

    Is Mobile 1 high detergent?
  • amoraamora Posts: 204
    INHO if you plan to turn in/trade-up in 2-5 years go with the Pepboys ProLINE oil/filters, if you
    intend to keep vehicle 10-100 years go with the
    Mobil 1/filters...
  • this discussion (aka: Petroleum or Synthetic... That is the question) has been moved from the Archived Pickups folder to this board. Happy Motoring!

    Pickups Message Board
  • I've used Mobil 1 for 11 years in my 1990 F150. My 2001 F250 requires 5W20. What do I do now.? Do any of the synthetics come in a 5W20?
  • axle59axle59 Posts: 28
    I used to have an '84 civic that got 32mpg. I started using synthetic and my mileage went up to 36mpg. Ever since that time I have used nothing but synthetic oil. I just bought a 2k1 nissan frontier and will be putting synthetic in it after the inital 3k oil change. As for the additives I reccomend using prolong. I had a buddy put it in his sentra and he drove all the way from Barstow to San Diego in the middle of the summer with no oil. Not on purpose he just failed to check his oil before he left. No engine damage at all. One more thing on synthetics. If you are gong to use on I would only use the Mobil 1. I used to use Castrol Syntec but I found out that they changed their formula last summer. They are now using a modified petroleum base instead of a true synthetic base. Mobil took them court over it and the judge upheld Castrol's end stating that a modified base can be called synthetic because it has been altered. Funny thing too is the modified stock only costs about half as much to make but Castrol is still selling it for $4.25 a quart.
  • I have always had good luck with Valvoline. Does anyone know about, or has anyone had any experience with Valvoline's synthetic product? Just curious.
  • I just bought a 2001 F250 Crew 4WD with the V10. They recommend the 5W-20 oil, I can't find Mobil1
    in that viscosity! Auto Zone had no oils AT ALL of that type!!!! HELP! I am sure I can substitute 5W-30 in Mobil1, but am worried my gas mileage will get worse than the 12mpg I now get?
This discussion has been closed.