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Engine Oil - A slippery subject Part 2

mznmzn Posts: 727
Here's the spot for all your engine oil questions
and answers. If you're looking for Part 1 of this
topic, it's right here.

carlady/roving host


  • ghtrapghtrap Posts: 26
    Well, let's start the oil topic #2.

    I was a die hard 10w-30 user until about a year ago and finaly gave up and went with 5w-30 like my owner's manuals said for both my Accord and Explorer. I actually picked up some gas mileage, but I do believe the greatest benefit to the engine is upon start-up - flows better in a cold engine.

    Even though I have nothing against it, I still am too much of a die hard to go with synthetic. I'm one of those who uses Quaker State dino and changes every 3,000 miles. My engines last very well.
  • After reading the last two posts, I'm inclined to agree on 5W-30. I was surprised to hear that so many manufacturers suggest that viscosity. I haven't made up my mind on synthetics, though. I've read previous posts suggesting that synthetic users have to crank their engine less during the winter (better start up). I wonder if the difference is as pronounced with a 5W-30 weight oil as a 10W-30... I don't exactly live north of the artic circle (Ohio), so I wonder if this is a moot point.

    I've always changed at 3-4K also, depending on manufacturer recommendations. Don't know if it's really needed, but I'm not going to second guess the engineers who designed my car.

    ghtrap--just out of curiosity, do you notice better starting all year or just in winter?
  • inkyinky Posts: 370
    I noticed that OLDs recommends 10w30 for the intrigue with 3.5 l. IT is posted on the oil filler cap. MOst other cars do recommend 5w30 and that is what I use in my Lexus ES300 and Honda Odyssey. If you want quick lubrication at start up to reduce engine wear and you do not drive near redline continually a good 5w30 should do the trick. I would admit that 5w30 would not lubricate properly say a Honda Civic that goes to high rpms a lot in warm summer months.
  • btroybtroy Posts: 92
    5-30 and 10-30 will have the same viscosity under high temperatures. The only difference is in low-temperature viscosity.
  • rs_pettyrs_petty Posts: 423
    But I believe one reason 5w-50 is not recommended by the manufacturers is it is only available from a few companies and in synthetic. They have to conform to a wide consumer base. I wonder if the engine would even know if it had 5w-30 or 5w-50. Perhaps though on second thought it would create too thick of an oil layer in the lubrication system causing oil pressure to be too high leading to seeps & leaks and possibly reducing gas mileage.
  • SporinSporin Posts: 1,066
    Best of both worlds? Opinions and experiences?
  • rs_petty: I'm inclined to think that you are right about that being too think. That's the same as 20W-50, and my guess is that tolerances are probably too tight. As per my previous posts (and answers to it), it looks like most of the manufacturers are getting away from that heavy stuff.

    sporin--I don't think I would ever use a synthetic blend. I checked out the numbers, and they are virtually identical to conventional oil. I've seen posts here where the amount of synthetic oil in the blends is MAX 25% (some only 10%--I know that number for sure). You'd be economically better off to buy a quart or two of synthetic for your next oil change and mix it with the conventional oil (they're all fully compatible, but you could get Castrol Syntec and Regular Castrol, if it gives you greater peace of mind), and you'd get a higher % synthetic (that's all the manufacturer does--there's nothing special about the blends. Just more money.

    My question--anyone know anything about Motorcraft oil? It seems to be more expensive, and I wonder if it's actually made by Ford or if they just slap their name on it.
  • ccotenjccotenj Posts: 610
    in my bimmer. mobil 1. i was amazed the first time i poured syn out of a bottle. the stuff flows like water.
    i noticed when i put syn in my f150 that it just "sounded" better at startup. could be a placebo effect.
    comment on syn blends. frankly, worst of both worlds, imho.
  • Can anyone share their long term experience with using synthetic in a turbocharged engine? I'm considering changing from dino to Mobil 1 in my '94 Volvo 940 which just turned over 100k. I am especially interested in frequency of synthetic oil changes for anyone with a turbo. I plan to run Mobil 1 with the A-C Delco Ultra-guard Gold filter in my new Honda Odyssey LX and change oil every 7500 mi. (Thanks for the filter suggestion Inky!)
  • ghtrapghtrap Posts: 26

    I can't actually say that I can tell the difference between 5W-30 and 10W-30 upon start up whether its summer or winter, I just believe in the theory that the 5W-30 should flow better to the upper portions of the engine when cold.

    I live in Kansas, so I don't even have the winters that you do in Ohio. You may or may not be able to tell a start-up difference with the 5W-30 at very cold temperatures.
  • inkyinky Posts: 370
    I switched to mobil one 5w30 from conv 10w30 and get 2 mpg better in very similiar driving-almost identical. It also starts easier. I will run for 6,000 miles to get my money out of it.
  • SporinSporin Posts: 1,066

    I am figuring to go to Mobil 1 5W-30 at 20k miles, with 7500± mile changes. car is a 99 Passat 1.8 Turbo. Owners on and have reported...
    • better mileage
    • easier startup in cold weather
    • cooler running temps

    ...when switching to Synthetic.
  • treyh1treyh1 Posts: 34
    How much oil is normally used between changes? I've got a 5 qt capacity & when I pour up the old oil to recycle it I usually get just a little over 4 qts. I change every 3500 miles; the truck is a 3.0 Ranger with about 35,000 miles on it. Is this about average for oil usage?
  • ccotenjccotenj Posts: 610
    it's normal for ford trucks to burn oil... i don't know why, but everyone i know (plus myself) who owns one says they do, and the service rep at the dealer said that it's normal....
  • div2div2 Posts: 2,580
    Most of today's carmakers don't consider oil consumption excessive until it exceeds one quart in 1000 miles. No way would I worry about one quart in 3500. You should be OK for many thousands of miles to come.
  • ruking1ruking1 Posts: 18,333
    I have a 94TLC that uses one quart or so in 14,000 miles. It has app 65,000 miles on it.
  • Hey everyone,
    As far as the choice between the two viscosities, I thought the 50 weight would be better in hot temperatures/long hard driving conditions. Since the 50 refers to the high end temps. I have not read or heard of any manufacturers recommending it but it seemed logical to me. 4 cylinder engines do have to work harder, get hotter, so should need more protection. Since I am not an expert on motoer oils, I will defer to those who know more. But I do think that a synthetic 5W-40 at least should be a good bet in a new engine (I just turned 850 miles on my 2000 Tiburon). I Would appreciate any additional comments on this subject, maybe someone who has actually tried 5W-50. Or maybe a mechanic.
  • Use what your manufacturer recommends. Too wide a viscosity range is bad because the extra polymers added to make wide viscosity range can breakdown and cause problem per oil FAQ:
  • My theory is:
    Synthetic oil is known to flow much better at low temperatures and therefore there has to be less wear during the warm up.

  • I don't think anyone would argue the point that synthetic is better at start up. It is better for everything. The real question is--is the cost justified? I'm still trying to make up my mind personally. I mean, I've always changed oil according to manufactuer recommendations and have never had an oil related problem. If you use synthetic, your engine might last much, much longer. But if all the other parts on the car are falling apart first, is it really worthwhile? Dino might make it last to that point also. That's the dillemma...
  • if syn oil stays in your car a long time the acid from the combustion process builds up.
    Changing regular oil gets rid of it.
  • Consumer Reports tested several motor oil including synthetics in NY taxi cabs. Reported about 1997. Synthetic fared no better than other top oils. But, the test was conducted with very long running times, therefore few cold starts. My conclusion is the only advantage (unproven) is helping reduce wear during cold starts and warm up.
  • ruking1ruking1 Posts: 18,333
    Further on in the same article, they say that they couldn't complete the tests for synthetic due to mechanical failure of the vehicle not related to the oil.

    With the extreme oil changes at 3k as advocated by myth, marketing, fear, etc, the synthetic is clearly not worth the extra cost. However keep in mind that you are using 2x to 5x the product. So if you go from 7.5k to 15k between oil changes, it starts to offer scale of economics also.
  • For the cars that have the oil change puters, like MB and I think some GM trucks -what change interval is called for?
  • SPYDER98SPYDER98 Posts: 239
    I have been using synthetic now for about 7000 miles in my turbo eclipse. I've done 2 oil changes at 4000 mile intervals and I honestly do not see a difference in anything. Except the extra 20 bucks I dish out at the shop.
    The synthetic is turning dark just as quickly as conventional was.

    But I do think the word synthetic sounds better than the word conventional.
    Don't ya think?
  • sdc2sdc2 Posts: 780 interview with a racing team some years ago when synthetic oil was still relatively new, and they talked about their experience. Before with conventional oil they had to rebuild their engines after ever race. The first time they used Mobil One, they tore down the engine and found everything was within original specs. After that they found they could go four or five races between rebuilds.

    That is a pretty significant difference. The question is, is it relevant to our situation? None of us rev as high or run at the temps racers do. And they don't give a rip about cold start attributes.

    I can tell you that I decided to go to synthetic about 12-15 years ago, and none of my vehicles have EVER needed to add oil between changes. Some of those vehicles were well over 150K miles.

    I just don't feel that $20 for an oil change (I change my own) is too much to spend every 3,000 miles, when you look at the expense of the vehicle. Conventional oil would save me a whopping 0.4 cents per mile. AAA says we pay something like 35 cents per mile to operate a vehicle, so the "expense" of synthetic is just not that burdensome.

    And finally, I do feel that the cold start thing is big here in Minnesota, where occasionally I have to start at -20F or lower. If you have never had the pleasure, your car sounds like a coffee can full of rocks at that temp, until it warms up after 15 minutes or so :)
  • rs_pettyrs_petty Posts: 423
    12,000 miles annual
    conventional oil change - 3000
    synthetic oil change - 6000
    6 qts per change

    Syn: 6 x $3.65 x 2= 43.80
    Con: 6 x $1.25 x 2= 30.00

    Less than 15 bucks over the year. My view is that synthetic may not be noticeable when an engine is new, but at 60-100k I hope to see engine performance remain rather than start to taper off because of worn engine parts. Same could be said for using synthetic lubricants in other mechanicals like trans, rear-end, PS pump. I need about 10 years of reliable service out of my vehicle.
  • dhanleydhanley Posts: 1,531
    With conventional oil, I stick to 3K change intervals. With synthetic, I feel that I can do 6K change intervals. That about cancels out the extra cost of the synthetic due to fewer visits for oil change. I do have to add about a quart between, typically. It still costs me a bit extra, but, as a previous poster said, if it gets me one more month out of my car, it's worth it. I put about 40K per year on my car, and I plan to take it to 150K miles or so. The only reason I've worried about it is that I expect the car would get to 150K miles on regular oil with no problems either. Still, since the extra cost is so small, I don't worry about it too much.

  • I've used Mobile 1 5W-30 in my 94 Jimmy since it's first oil change with no problems. The vehicle now has 75K miles and runs like new. In 94, GMC provided the first oil change free using Mobil 1. My decision was based on the fact that I tow a pop-up camper during the summer months and tend to drive at 75 mph, even when towing. I think the greatest benefit in my case is that under high heat conditions, I know I can count on synthetic oil. I change my oil every 5000 miles. BTW, I usually can find the oil on sale for about $3.50/quart or buy it from a wholesale club for $21.50/6-pack. I get GM filters for $1.99 on sale in K-mart. Thus, since I change my own oil, an oil change costs about $20 with tax. For my 2000 Silohuette, I'll use dino oil every 3000 miless only because it looks too difficult to change it myself. I will also use this vehicle to tow the trailer.
  • rs_pettyrs_petty Posts: 423
    Have any facts/studies been done on normal cars/trucks? What happens to oil when a car is not used regularly on weekends or is only used on
    weekends? What effect does moisture and acids play on oil life? At what point does the oil/filter combination lose the ability to protect the engine? Is it 3k or is it closer to the factory recommended changes approaching 6k or 7.5k (some are even longer)? Posts on other topics have said that oil life, measured by contaminate suspension, is around 5k. I'm not sure this is definitive and is certainly effected by driving conditions. If suspended contaminates are the real evil causing oil changes then logically air quality conditions would effect this - then why is stop/go city driving touted as a major reason for oil change - seems to me it would be harder on transmissions (hince ATF) than engine oil, but I don't see or hear about 3k ATF changes. I use to change air filters with oil changes, but factory schedules are showing 15k or a year between changes. My understanding of combustion engines would lead one to say that a dirty/inefficient air filter allows more dirt into the engine than anything else (the only other avenue is internal wear of components).
    There is suppose to be less wear with synthetics
    so therefore there should be less contaminates in
    the oil with synthetic. Should air filters be
    changed more often? I ask these questions because
    of my experience with the Army's oil analysis
    program. The two major reasons for the program
    were to get an early identification of engine
    failure either through component wear or dirty air
    filters. You did not want an analysis returned
    indicating dirty air filters (trust me). Component wear ID allowed better logistics planning, service schedules and ultimately better readiness. What I am trying to think through on this post is a 3k oil change with conventional oil better than 7.5k oil change with synthetic oil. If I believe the 3k oil change story then logically I should look at more frequent changes for other fluids that also get contaminated. If I believe the factory recommended schedules, but just want to use IMHO a better quality lubricant then I should also get a satisfactory service life. I'm not sure there is an absolute answer to this question, but I love my truck and want to keep it that way.
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