1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Buick V6 - 3.8L 231 Oil Type?

Discussion in '40- & 55-Series Tech' started by cosfj40, Dec 11, 2009.

  1. cosfj40

    cosfj40 Regular Member

    Messages:
    150
    Location:
    Colorado Springs, CO
    Based on the intake casting number I was able to ascertain the motor I have in my FJ40 is a Buick V6 - 3.8L 231 (1976 I'm assuming). I've been able to nail down most of what I need for a tune up and oil change, but wanted some opinions from those in the know regarding what type of oil to use and am hoping someone knows how many quarts are required. I'm thinking of using Castrol Syntec 10W-30. Thoughts? Opinions?
  2. dgangle

    dgangle total rice SILVER Star

    Messages:
    4,006
    Location:
    Heart of Dixie
    anything of a reasonable grade will work just fine...5W30, 10W30, 10W40, 15W40.....all depends on how much you wanna spend. if spending more makes you feel better, go for it. Plenty of unwinable debates gone on over the years as to what is 'best'. Full synthetic caused my freshly rebuilt SBC to leak like a sieve. Add a Zinc/Phosphorus additive (cam break-in additive) if you are running a non-roller cam and you will be fine. Fill it to the full mark on the dipstick. That's how much it takes.
  3. cosfj40

    cosfj40 Regular Member

    Messages:
    150
    Location:
    Colorado Springs, CO
    Thanks for the tips, especially the part about filling it to the full mark. :doh: Guess I'll go ahead and buy two five quart bottles. I don't think I'll go for the synthetic after reading what you typed. That would really suck re the leakage.
  4. zebrabeefj40

    zebrabeefj40 New Member

    Messages:
    3,094
    Location:
    southeastern IN
    My family owned a couple vehicles with that motor back in the day. IIRC they liked a little heavier oil than 10w30. 10w40 is what we ran in them. Both vehicles lasted over 175K miles without a rebuild on the motors.

    :cheers:

    Nick
  5. Poser

    Poser Oh...Durka Durka Durka. s-Moderator Supporting Vendor

    Messages:
    19,623
    Location:
    MN
    Any oil is better than no oil... :lol:


    :meh:
  6. grant5127

    grant5127 New Member

    Messages:
    5,021
    Location:
    Meridian,TEXAS
    Its a well known fact that you don't do syn. till break-in / oil consumption usage has been established.........
  7. dgangle

    dgangle total rice SILVER Star

    Messages:
    4,006
    Location:
    Heart of Dixie
    i know that. I didn't say it CONSUMED it. I said it LEAKED it. Do gaskets have to 'break in'?
  8. donny paradise

    donny paradise New Member

    Messages:
    613
    Location:
    Paradise
    Why did you put it in then?

    Leakage is consuming.
  9. dgangle

    dgangle total rice SILVER Star

    Messages:
    4,006
    Location:
    Heart of Dixie
    not to me. i and the rest of the free world define 'consumption' as oil being burned, not leaked.


    i put syn oil in after break-in and it caused leaks. the engine it did not burn it.
  10. grant5127

    grant5127 New Member

    Messages:
    5,021
    Location:
    Meridian,TEXAS
    Consumption pattern and break-in period are critical before adding syn oil to a "freshly rebuilt" motor...... did you not want the rings to seat?

    You must have gotten a bad sealing job on your "FRESH BUILD".... Its commonly known leaking problems associated with syn lube are older high mileage......

    Anyway.... I would never admit to adding syn to a new or fresh engine in public...........
  11. dgangle

    dgangle total rice SILVER Star

    Messages:
    4,006
    Location:
    Heart of Dixie
    The synthetic oil was used after proper break-in with dino oil.

    The sythetic oil showed up as leaks on the outside of the engine.

    The synthetic oil was not consumed.

    I went back to dino oil and no more external leakes.

Share This Page