Oil pump lost prime?

Discussion in 'Small Block Tech' started by cb3071, Sep 19, 2018.

  1. cb3071

    cb3071 Well-Known Member

    Have a 1971 350 that sat for a couple of months without driving. Ran fine before it was parked. Went to crank it up and no oil pressure. Can the pump lose its prime? Oil needs to be changed but is not low. Any ideas?
  2. TrunkMonkey

    TrunkMonkey Well-Known Member

    Check for leak (gasket) or crack around the pump/timing cover housing.

    The way the Buick 350-455 oil pump sets, it should not lose prime unless the oil leaks out, but as far as I know, it should not siphon off.
    Oil gauge supply lines can get plugged, as well and cause a low or zero pressure indication.

    A fast test would be pull spark plugs and the oil sender and crank it. You should have enough pressure to see if the pump is working, then verify the gauge and try starting. (no oil pressure in the first few seconds of running, shut it down)

    If it's good, you can send me a bill for all the paper towels. :D

    If it has lost prime, you likely will need to pull the filter housing off the pump (and be careful about shims and the spur gears dropping out) and repack with Vaseline.

    You might be able to push enough oil through the oil sending unit boss on the block.

    Someone else may have another method that works.
    Last edited: Sep 19, 2018
  3. alec296

    alec296 i need another buick

    Do you have a gauge on it? . A few months should not have been a problem.
  4. cb3071

    cb3071 Well-Known Member

    No leaks at all. Clean around filter, pump etc. Electric oil gauge and is receiving current. Cranked it up and it ran but light grey smoke came out of the exhaust and it did not smell like burnt oil(never happened before). Ran it for about 15 seconds and shut off...My son did the same a week or so later and same results. Dummy light stayed on and it usually turns off after a few seconds. Any other ideas??
  5. gstewart

    gstewart Well-Known Member

    Maybe remove the distrib and use a priming tool (i use an old distrib shaft with a 1/4" headless bolt welded on the top end. Attach it to an electric drill, insert the priming tool into the pump and power on. If it primes u will fell it pumping oil. That may work otherwise u will have to follow TrunkMonkey's suggestion.
  6. BuickV8Mike

    BuickV8Mike SD Buick Fan

    Check oil pressure with a mechanical gage replacing the sender is what I would do.
  7. alec296

    alec296 i need another buick

    Pull the sender out and try to fill pump with oil .
  8. gstewart

    gstewart Well-Known Member

    Never thought of that. worth a trial.
  9. UNDERDOG350

    UNDERDOG350 350 Buick purestock racer

    I had a 3.8 V6 that did that. I let it idle for 1 minute with no oil filter on it and no oil came out. On tear down I found the plastic cam gear teeth plugged the oil pickup screen.

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