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oil weight ?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by riz, Oct 1, 2001.

  1. riz

    riz 3/4 ton status

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    <font color=purple> I have a weird question about oil weight .......... I just did an oil change on our 2000 Stratus and they recommend using 5w30 but all I had was 10w30 because that's all I've ever used in cars that say to use 5w30. Am I wrong in what I've been doing ? What are the pros and cons ? I used to own a Pontiac Sunbird and when I used 5w30 it would leak but not with 10w30 ........ I know the difference of the thickness but what else is there ? Another question on the subject ............ would changing oil weight improve gas mileage ? I've never thought of it before and I thought I'd ask. I never had problems running the 10w30 in the Sunbird at all and the car ran like a top .........any thoughts ???

    L8r,
    . Riz . <a target="_blank" href=http://www.geocities.com/rizmonkey>www.geocities.com/rizmonkey</a>

    <font color=purple> BOW CHICKA BOW WOW !
     
  2. Blazer_Boy

    Blazer_Boy 1/2 ton status

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    Well I'd just run synthetic because it'll run circles around dino juice in extreme conditions. I don't have a scientific answer for you but I noticed when I rebuilt the top end of my old man's '89 Jimmy it had the 5w-30 listed on the oil cap and some crap about energy conservation. I just dropped 10w in it and said forget. Better pressure if you ask me.

    <a target="_blank" href=http://www.geocities.com/bigkern76>http://www.geocities.com/bigkern76</a>
     
  3. Jeff427

    Jeff427 1/2 ton status

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    There are at least two reasons that the manufacturer recommends 5w30 rather than 10w30. the first reason is the 5w30 lubricates the motor faster on start up. The second reason is lighter oil is easier to pump, so there is less parasitic power loss at the oil pump. Higher pressure is not necessarily a good thing, especially if the pressure is good to begin with. This just means you are wasting more of the motor's power pumping oil.

    Jeff427
    <a target="_blank" href=http://muddog.off-road.ws>Mud Dog Off Road Club</a>

    <a target="_blank" href=http://lyonsdesign.bizhosting.com>Lyons Design Web Site</a>
     
  4. 84_Chevy_K10

    84_Chevy_K10 Banned

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    In my opinion, when it's above freezing, 10W30 is better. The oil manufacturers have to add things to the oil to make it lubricate like 30 weight and flow like 10 weight, and the bigger the range between the numbers, the more they have to add.

    The lowest range is usually best as long as you're good to go in the temperature range you're in.

    When it's below freezing, use 5W30, as you'll need it on cold starts.

    I run 5W30 Mobil 1 in mine now, but I'll switch to 10W30 or 15W40 in the spring.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     
  5. Blazer_Boy

    Blazer_Boy 1/2 ton status

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    Orrrrrrrr, just do the synthetic so you don't have to worry about oil weight as much at colder tempatures.

    <a target="_blank" href=http://www.geocities.com/bigkern76>http://www.geocities.com/bigkern76</a>
     
  6. dragricinMT

    dragricinMT 1/2 ton status

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    There's talk ofthe manufactures going to 0-30 oil. Some are running 5-20 also. Valvoline just come out with 5-20 recently.

    78-K5 4"Lift 35"Tires 400SB TH350 NP205
    73 Vega 350SB TH350
     
  7. CaptCrunch

    CaptCrunch 1/2 ton status

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    Yeah basically the cold start up and fuel milage are big factors. Also bearing clearances are getting much smaller which is another reason for the change. You should be ok for this O/C but I would recommend going to 5w30 next time and there after or synthetic.

    Yup... 0w30 is already out in some places. Heard of a few cars requiring it.

    -Mikey
    1987 Chevy K5 Blazer- 350 TBI
    <a target="_blank" href=http://coloradok5.com/gallery/captcrunch>http://coloradok5.com/gallery/captcrunch</a>
     
  8. DesertDueler

    DesertDueler 1/2 ton status

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    I run straight 50 weight in the Firebird. I run 20w50 in all my other vehicles. The lighter weight in AZ breaks down too quickly. If you live where it is cooler I would recomend 10w30.

    86Jimmy 4"&35"MTRs,87 burb 4"&35"MT,69Firebird w/525 hp,and 70GTO live in PHX,AZ<a target="_blank" href=http://www.geocities.com/modifierperformance>My vehicles</a>
     
  9. Triaged

    Triaged 1/2 ton status

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    84_Chevy_K10 has it right. 10W30 is better than 5W30 in every respect except for cold (below freezing) starting.

    Also I agree with every one else that syn. is much better.

    '71 Blazer CST w/ a 400sbc, 4" lift, 36" Supper Swampers, and alot of rust
    <a target="_blank" href=http://community.webshots.com/user/triaged>See it Here </a>
     
  10. wayne

    wayne 3/4 ton status

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    I hate to disagree with some of you guys on this but I would say run the 5w30 in it. In Donna's Sunbird they say to use 5w30 and I found out why when I used 10w30. With the 10w30 the car was a total dog for power. I do not know why it made such a noticeable difference but it did. I use 5w30 in it all year even when we lived in Georgia (BTW it was a hot summer in Ga when I tried the 10w30) and change it every 5 to 7000 miles which is what GM recommends for a car that gets alot of highway miles and it just turned 165,000 and not a problem yet.

    See <a target="_blank" href=http://coloradok5.com/gallery/Waynes-Toy>Project Mighty Mouse</a> here.
    <font color=blue>Wayne<font color=blue>
    <font color=blue>Happy Trails<font color=blue>
     
  11. DesertDueler

    DesertDueler 1/2 ton status

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    MAybe I dont notice the power difference because all my vehicles have decent power :) Seriously though I have built alot of race car motors and you can tell who used 10w30 and who used straight 40 or 50 weight. The ones with the thicker oil have alot less wear on the parts. As for synthetic I wouldnt recomend it. It is too thin and have way too many problems with it in the cars. When the synthetic gets hot it thns out so much that it blows by the rings and you burn the oil.

    86Jimmy 4"&35"MTRs,87 burb 4"&35"MT,69Firebird w/525 hp,and 70GTO live in PHX,AZ<a target="_blank" href=http://www.geocities.com/modifierperformance>My vehicles</a>
     
  12. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I know about 5W-20. What I don't know is how they achieved it without using synthetic, well, Motorcraft anyway. Penzoil 5W-20 is a synthetic blend.

    I work at a Jiffy Lube and we have to charge twice as much for an oil change that uses 5W-20 because of what we pay for the oil.

    Ford switched to 5W-20 for emissions purposes. They couldn't pass with 5W-30 supposedly, so they went with 5W-20.

    I personally wouldn't put anyting thinner than 5W-30 in anything unless the manufacturer required it (and I wouldn't own a vehicle if the manufacturer required it). I don't belive in thin oil at all.

    Thin synthetic oil sucks for oil pressure. I have the 5W-30 Mobil 1 in mine and I only get 15-20 PSI hot idle with a high volume, Melling oil pump and a 3,000 mile engine. I just don't like it to read that way. But I'm not going to drain out $40 worth of good oil.


    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     
  13. wayne

    wayne 3/4 ton status

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    Ok now we are not talking about 400 or more horsepower.[​IMG] We are talking about a newer 4 or 6 banger. Funny thing is I looked at the Sunbird over the weekend and the wheelbase is very close to a K5. Wonder what a Sunbird 4x4 would look like with a v8 under the hood?[​IMG]

    See <a target="_blank" href=http://coloradok5.com/gallery/Waynes-Toy>Project Mighty Mouse</a> here.
    <font color=blue>Wayne<font color=blue>
    <font color=blue>Happy Trails<font color=blue>
     
  14. Gandolf

    Gandolf 1/2 ton status

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    In our warmer Cali climate, I run 10w30 until the engine has 100,000 miles on it, and then switch to 20w50 after that. I also change the oil and filter every 3000 miles. I've been doing it that way for years with excellent results. My Blazer's engine now has 159,000 miles on it, and still runs strong.. It has good, equal compression and burns a quart of oil every 3500 miles (before the last oil change, I went longer just to see how far it would go before it was exactly one quart low).

    Valvoline 20w50 with Napa Gold Filter in the Blazer.
    Castrol 20w50 with Napa Gold Filter in the Nissan 280ZX &amp; 560SEC Benz.

    I would consider synthetic in a new engine.

    '89 K5 Silverado..."You can’t have a real adventure, unless the outcome is truly uncertain".
     
  15. 83ZZ502_Jimmy

    83ZZ502_Jimmy 1/2 ton status

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    I have used pennzoil 10W30 in my '89 S-10 with a 4.3 since it was new. It now has 287,000+ on it. This is the original motor. I live in VA and towed a 3500lb boat in the summer for 2.5 years. The motor still runs strong. I change the oil every 3000 religiously.

    My .02,
    John

    <font color=blue>"When all else fails, read the instructions, or get a bigger hammer"</font color=blue>
     
  16. muddin4fun

    muddin4fun 3/4 ton status

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    I'm running 10w30 Mobil 1 in my truck. It seems to be the best for Texas weather to me. A lot depends on your climate too..

    <font color=blue>Women should put pictures of missing men on beer cans...</font color=blue>
    Website link is in my profile [​IMG]
     
  17. taterblazer

    taterblazer 1/2 ton status

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    Synthetic

    I'm under the impression that if you goto synthetic you shouldn't go back to normal oil? The reason I won't run synthetic is that I have to put in an extra quart every now and then. Cheaper to put regular oil in.
     
  18. jarheadk5

    jarheadk5 1/2 ton status

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    Bingo on the additives. In PETROLEUM oil, the viscosity range (10w30, 15w40, etc.) is determined by the type and amount of "viscosity modifiers" the manufacturer adds to the base oil. The bigger the split between numbers, the more modifiers have to be added, thus reducing the amount of actual lubricating fluid in a given quantity of the finished product. Not much of a difference, but it's there. Plus, some of these modifiers are somewhat heat-sensitive, and WILL eventually cook out of the oil, thus changing the viscosity of the oil with age.
    Now SYNTHETICS are specifically brewed to have the viscosity they are labeled with. They don't need a viscosity modifier because the viscous properties are engineered into the base stock. This is one of the reasons synthetics are better in high-heat applications. Plus, synthetics can generally get a better friction-modifier package because there's not a overload of additives crowding out the actual lubricating fluid in a given quantity.

    5w30 in my wife's Eclipse year-round (63K mi.), 10w30 in my K5 year-round (119K mi.). Both are the manufacturer's recommendations for the temp range I encounter.

    September 11, 2001--"A date which will live in infamy"
     
  19. FRIZZLEFRY

    FRIZZLEFRY 1/2 ton status

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    I just run straight 40 when its hot,30 when its cold.

    A balanced diet is a beer in both hands.<a target="_blank" href=http://community.webshots.com/user/beaterwhang>community.webshots.com/user/beaterwhang</a>
     
  20. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I bet that's rough on cold startup! Straight 30 when it's cold? How cold?

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     

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