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HEY 5.7L owners (OIL SPECS)

Discussion in 'The Garage' started by adamforsythe, Feb 18, 2005.

  1. adamforsythe

    adamforsythe 1/2 ton status

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    What kind of oil do you run through your engines?
    I run 10-40 all year long. I tryed running 30W through her last summer and she did not like that to much. I even tryed it a few weeks ago seeing if the winter time had any effect. Well she did not like it to much.

    It is a new rebuilt (10,000 miles on the engine).
    Thanks
    Adam
     
  2. Jonny-K5

    Jonny-K5 1/2 ton status

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    either 10-30 or 10-40. my truck's got 150k tho. doesnt burn any oil w/ 10-40. about 1/2 quart per oil change with the 10-40.

    for a newer rebuild i'd run 10-30, nothing thicker. if you live anywhere cold(BTW fill out your profile to make it easier for others to answer your ?'s) i'd go with 5-30
     
  3. adamforsythe

    adamforsythe 1/2 ton status

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    I just filled out my profile.
    Thanks
    Adam
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    Not trying to start a flame war here, even though that is what most oil threads turn into but...

    10W40 apparently has no place in a modern engine. It was a LONG time ago that I read this, but apparently the "spread" in viscosity of 10W40 is too much, and it just isn't an effective oil, and isn't recommended by anyone these days. Why it still seems to be so common on store shelves if that is true, I don't know.

    If you look at owners manuals (not sure what my 86 K5 one says) more likely than not, 10W40 won't even be listed as an alternative in the chart listing conditions/recommended oil.

    I run 10W30 in my new motor, and it DOES seem to lose a bit of pressure "faster" than the 20W50 I *used* to run on my old motor, but it's not like it drops to 15PSI at hot idle or anything.

    From what I saw of your other post, the oil alone won't make that kind of difference...you might see a difference in the pressure, but I wouldn't expect anything over a 10PSI difference, just to throw a number out.
     
  5. muddysub

    muddysub 1 ton suburban status Staff Member Moderator GMOTM Winner

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    i have to run 20w50 now... it goes through 15w40 like the exxon valdez (1.5qts/week)
     
  6. Jonny-K5

    Jonny-K5 1/2 ton status

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    my k5 says to run 10-30 in warm climate. where it gets below freezing run 5-30. it says 5-30 on the oil cap. i think you should run the lightest possible oil in new motors. as it wears, increase to higher numbers as needed, but only if its burning quite a bit of oil.
     
  7. 79Beast

    79Beast 1/2 ton status

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    I did initial startup and break in on non-detergent 30 weight. Since then I have run 10W40 summer and winter. To date I have some pretty rough miles on that old 355 and I haven't had any oil related problems. Good and warm oil pressure is 18-20 psi at idle. Dead of winter cold startup oil pressure can spike to 60 or so....I try to keep the revs down until it gets warmed up a little.
     
  8. ssls6

    ssls6 Registered Member

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    You are correct but dated. The 10w-40 of the late 70s and 80s used viscosity improvers (thickeners) that were unstable. When they broke down, you were left with a 10w oil in a motor designed for something thicker. The viscosity improvers of today are very stable and it is no longer an issue.

    One of the best things you can run in these older V8 chevys is diesel oil. Delo 400, Delvac, or Rotella will perform better in these engines than the modern SG car oils. The goverment has forced oil makers to lower the Zinc/Phosphorus in modern car oils because it kills the catalytic converter. Zinc/Phosphorus is the primary antiwear additive used by the engine.

    I personally run the 5w-40 rotella synthetic oil from Wal-mart. It has a better additive pack than anything on the car oil section.
     
  9. 4by4bygod

    4by4bygod 1/2 ton status

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    <<One of the best things you can run in these older V8 chevys is diesel oil>>

    I'll second that. I run a diesel quality 15w40 in my 87 K5 dd ( 210,000 mi) with a 305. I'm running a brand called Quantum Blue, which has superior anti wear / anti shear capabilities not found in other oils.

    Here's a link to an article in Popular Hot Rodding, describing the oil's performance compared to mobil 1 in the Zo6 crate motor, and you can find the manufacturers contact info at the end of the article.

    http://www.popularhotrodding.com/enginemasters/articles/chevrolet/smallblock/0503em_ls6/

    If you want to see my own oil analysysis with wear numbers, PM me. I don't work for the company, but I am tight with the owner, and an enthusiastic user of the products.

    Tom
     
  10. adamforsythe

    adamforsythe 1/2 ton status

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    Hello,
    See when I run 10W-30 in my engine it just burns it when I get on it. So that is telling me that the oil is not up to the working cont of my engine. But when I run 10W-40 my oil pressure is where I want it. When it is cold it is high so I will keep the revs down intell my oil pressure goes down.

    But do you think a Synthetic 10W-30 would be better for my engine? I will try it if you guys think so.
    Thanks
    Adam
     
  11. 4xcrazy

    4xcrazy 3/4 ton status

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    HMMM, the last and only time i ran 15-40 wt diesel oil in a Chevy engine, i had to change out the cam and lifters shortly after, and this was an engine that was rebuilt about a year and a half before. the oil had broken down to the viscosity of water not long after it was put in,,,,

    Now with the Burb, 22k miles on it, never been rebuilt, i only run 20-50 and use really only 1 qt between oil changes of about 3000-4000 miles.
     
  12. mtn. burb

    mtn. burb 1/2 ton status

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    That is good information to know. Thanks buddy.:D
     
  13. Hossbaby50

    Hossbaby50 3/4 ton status

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    I run Valvoline 15w-40 oil in my truck. Seems to work fine for me. I used to run 20w-50 in the summer to help combat the AZ heat and 10w-30 in the winter but I got tired of switching back and forth so I went with the 15w-40. I figure if it is good enough for a Cummins Turbo Diesel it is good enough for my SBC.

    My Jeep gets straight 30w motor oil all year long.

    Harley
     
  14. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I use 5W-30 year round in my trail rig.
     

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