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Hell is an Unprimed Oil Pump, Episode 1

Tim Odell November 14, 2012 Project Cars, Wrenching Tips 27 Comments


After my last rant about my pain in the ass 1969 Jeep Wagoneer, I rinsed the sand from my underpants, put on my wrenching clothes and got to work on the damn thing. The most recent round of fixes was aimed at the most annoying problems: massive oil leakage and a carb that delivered too little gas to the motor and too much to the exterior of the intake manifold.

The intake manifold gasket and and carb rebuild, which I assumed would be the tough jobs, went smoothly. The auto trans pan gasket was a stinky mess, but otherwise easy enough. I’ll write up the carb at some point as a Wrenching Tips article, as I actually remembered to take pictures it’s usefully instructive on the general process.

Despite those successes, it’s the process of re-sealing my oil pump that’s got me throwing an angry monkey shit fit and hating this car all over again.

A little context and background. On paper, the Buick 350 is a perfect midsize truck engine. Slightly undersquare (3.80 bore, 3.85″ stroke), it made 230 gross HP and 350lb-ft at 2400rpm. Though really wide, it’s otherwise more compact and light than other smallblocks, tipping the scales just under 500lbs in all-iron form. Unfortunately, oil pressure is its Achilles heel. It doesn’t make nearly as much pressure as a typical motor: barely measurable at idle and maybe 30lbs cruising around at 2500rpm, brand new.

In an automotive corollary to Rule 34, there’s a forum and specialty manufacturer for every car or engine type out there. TA Performance is the place for Buicks, and they sell a cheap-and-easy $20 oil pump booster plate kit that’s supposed to help bump pressures out of the “OMFG no oil!” range.


Unfortunately, when you yank the cover off of the semi-external oil pump, it loses its prime. In this case (or with any brand new or long-sitting motor), you have to re-pack the oil pump gears with petroleum jelly to give it something thick enough to pull on. Failure to do so leaves your pump sucking air and your motor with no oil.

To date, this was the most frustrating automotive job I’ve had to do. Essentially, gravity issues a great big “F-U” and causes either the oil pump gears or petroleum jelly to fall out onto your face while you try to line everything up and not screw up the gaskets. I got it together and was rewarded with a slight bump in oil pressure…and a new oil leak.

That was last year. Fast forward to recent times, and I’m on a quest to de-leakify my engine. The leaky booster plate and teenie-tiny paper gasket come off. Being clever, I decide to replace the paper gasket with “Right Stuff” sealer. This works badly, as apparently gravity acts on it as well. Much grunting (instead of cursing because my 2.5 year old is helping me) ensues and finally it comes together in a “there, I fixed it” huff.

I get distracted with miscellaneous kid duties, then come back to the garage. The car fires right up and I immediately remember I need to open the back door of the garage to get some ventilation, lest I die of CO poisoning. I take the outside route, and come back in to check on the car…that’s apparently been running for a good minute or so with no oil pressure. Shit; it didn’t prime.

I tear it all down again. The Right Stuff is all over in ways it shouldn’t be, so we’ll go back to the paper gasket this time, with just a tiny monolayer of the stuff to hold it in place and prevent leakage. I pull the driven gear out to get a maximal volume of jelly in there then squoosh it back into place. I think the colder weather is working to my advantage, as everything’s staying in place better this time. Also I used a magnet to hold the gear in place. I wipe up the excess and slap the cover on…only to be pulled away on Dad duty again. Returning 4 hours later, the car once again fires right up (damn good job on the carb rebuild), but still no f***ing oil pressure!

Ok…round three…here we go…pull it apart only to find the original load of jelly still in there…looking either really viscous or completely unperturbed. No other signs of problems. I pack some more in there for good measure, bolt it up and (I’m learning by now) crank it with the ignition disconnected. Still no love.

At this point I contemplate rolling it into the street, setting it on fire and filing an insurance claim. I’m putting that in writing here to prevent myself from actually doing it, as my insurance agent/father-in-law reads the site (Hi Mark!). I also spend much of the next day at work checking the V8 Buick forums for help and browsing for vehicles I’d rather have. See exhibits A, B, C, D and E.

I like challenges, but this is more of a mystery…or really more like some kind of rigged carny game. I got it once, but just can’t seem to make it work again. Tune in tomorrow for when I get to the bottom of things…

 Note: sorry for the lack of pictures. The more frustrating and repetitive things got, the less time I had for pictures. Besides, it’d be the same shot of gears packed with Vaseline over and over.

  • matt

    why don't you prime it with a drill

    • You mean remove the distributor and stick something (chucked in the drill) down the hole to drive the pump? Does that work on Buick small blocks?

      EDIT: The answer is apparently yes. I went to Google "buick 350 oil pump prime drill" and found a thread on v8buick.com started by someone named mad_science where people suggest that, and also we see what his pump's underlying problem turned out to be. I guess that will be revealed here tomorrow.

      • SPOILERS!

        Also, you know it's bad when most of the search results for the problem you're having are the threads you just started.

        • What's worse is when you find an old thread detailing the problem that YOU presented a solution to. This has happened to me a few times, since I've been on the internet for over 15 years now.

        • Vairship

          If it were me, I'd probably go through all that only to find out that the oil pressure gauge had gone bad…

          And I guess there's one other way to prime the pump: turn the Wagoneer upside down!

    • 1) No priming tool available at the time, didn't want to spend 30 minutes making one when I hope to never do this job again.

      2) Even with a drill + priming tool it won't prime without petroluem jelly in there

  • delta5

    I've basically stopped using any gasket makers/sealants besides for Hylomar Blue. So far it's working great on: throttle body, head gasket, oil filter mount, water pump, upper oil pan (lower needs something thicker so Toyota FIPG Black there), intake manifolds, and I think another place I'm forgetting. Cured ALL of my leaks.

    • Irishzombieman

      I'm a big fan of black Permatex. Until I have to scrape it off. Then everything that I love about it bites me in the ass.

      Most common use: oil plug threads. Never had a single drop of oil leak out.

  • buzzboy7

    My mechanic had this issue when I had him do the top end of an engine I didn't feel comfortable working on(SBF). Turns out the oil pump drive had slipped and it wasn't turning. Doh!

    On the last engine I did this with(ACVW) we used grease. Super thick stuff. Pulled a prime amazingly fast. Then again, the ACVW has the oil pump nice and low.

  • "angry monkey shit fit"

    Boy I know that feeling well. Actually, that'd be a pretty good garage name.

    I've only ever dealt with this on a small block Ford, and for that you can get an oil pump priming tool attachment for your drill. I'm guessing that's not the case here?

    • You can, but that means you have to go get one…that the local chain may or may not have.

      You still have to stuff the thing with Vaseline, though, so the drill tool just creates extra work (distributor removal, re-timing) if you can get it to prime with the motor, as I'd done previously.

      • *shrug* it's the method I have always used, but then again any Autozone carries the tool for a Ford. No idea if it's the same or different for your engine.

  • skitter

    If it makes you feel better, I took my center console and dashboard apart, found a perfect matching gauge cluster in the junkyard, tested it, re-discovered the joy of a correct speedometer and tachometer. Now, I knew the speedo was wrong, because that car will not do 35mpg in first gear, but the tach? The correct answer is to swap them both. I did, put everything back together.

    It was the circuit board.

    Took everything apart, un-frankensteined the clusters, put it all back together…
    I kind of didn't even look to see if things were working.

  • JayP2112

    I like a good mystery- but nothing is safe from the internets. There is a forum for EVERYTHING.
    Now I gotta wait for tomorrow to see if you did the right thing.

    • jeepjeff

      Stu outlined how to find the spoiler above, but I'm waiting until tomorrow. Honestly, I have no idea what the right answer is or what is wrong. That just makes me more excited though, because I'm about to learn something.

  • gearz1

    That is an oil pump,not a grease pump.It cannot pass a lighter fluid(oil) when it is packed with grease.

    • TheOtherMacLeod

      The grease is pushed through, creating a vacuum, thus drawing the oil up into the pump (priming).

      • gearz1

        Lightly greased ,yes.Not packed tight.

  • PB Blaster + Benz-o-Matic torch + reasonably large hammer has always worked for me

    Soak it overnight and heat-spray-cool-heat-spray-cool a few times in a row.

    • jeepjeff

      Thanks Tim. I'm definitely going with hot wrench for the next step.

      • danleym

        A few months ago I rebuilt the front end on my 88 Blazer. Ball joints, tie rods, axle u-joints, everything. I'm pretty sure all of it was original, with 25 years and 190,000 miles on it. I took out a lot of aggression with that BFH.

  • Get a pneumatic hammer. Comes with a pickle fork attachment. I haven't met the ball joint or taper fit that it won't remove… yet.

    • jeepjeff

      Once I have my own garage, air tools are going in at the top of the list. Until then, I make do in sub-par conditions (it's a learning experience, I tell myself, it will make me appreciate the air tools better, I tell myself).

  • racer139

    Couldnt you make a primer out of an old.distrbuter shaft and some crafty welding. cut the top off and weld on somthing that will fit your drill…

  • Mister X

    Hmmm, never heard about the petroleum jelly/grease thing, I always used STP on the gears which is a MESS but it primed every oil pump I used it on.

  • dukeisduke

    "Right Stuff" sounds like the wrong stuff. Why not just go with the paper gasket, coated with good old Permatex #2? That's what I would use.

  • dave

    did you get it primed I am having the same issue and it is driving me NUTS I have had this pump and timing cove off a dozen or more times and packed it I even thought the gasket on the cover was bad I made a tool out of an old distributer I can get about 15 pounds at times with drill and than it looses it just wanted to see if you got it primed and how thanks