Oil Leak

Discussion in 'Street/strip 400/430/455' started by BrianM, Oct 19, 2021.

  1. BrianM

    BrianM Active Member

    Hey all, due to a run of bad luck I currently have 3 trucks not running in my driveway and had to make a road trip due to an unexpected death in the family. So I ended up driving my newly purchased untested 70 Riviera 1k miles over the weekend. In general it did really good but I have a really strange oil leak and looking for advice.
    When driving 60mph @ about 2300 RPM I have no significant issues and was getting 16mpg and had 40ish psi oil pressure. When I was running 75-80mph @ about 3000 RPM it was spewing oil like crazy and getting 14mpg and had about 55-60psi oil pressure. Oil is hitting the fan and getting slung over the entire engine bay so really hard to tell the source of the leak.
    I ran about 150 miles going 55-65 mph and was about an ounce or two low on oil when I stopped. When I ran about 100 miles going 70-80 mph it spewed out a full quart of oil.
    Previous owner tee'd in an oil pressure gauge along with the dummy light sending unit. I think it may be leaking from here but unsure. I plan to take all of the brass fittings off and teflon tape/ pipe dope them to see if that is the issue. What else could cause a high pressure leak at the front of the engine? What else should I check?
    Thanks,
    Brian
     
  2. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    The first thing you should do is clean the entire area with engine cleaner. Then determine exactly where it is leaking from. Then you fix that.
     
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  3. pbr400

    pbr400 68GS400

    Is the guage mechanical (runs a plastic or copper pipe to the guage)? If so, look for a split in the line.
    Patrick
     
  4. Max Damage

    Max Damage I'm working on it!

    Be careful with tape or pipe dope. You don't want any of it to get into the oiling system.
     
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  5. Mark Demko

    Mark Demko Well-Known Member

    I too would suspect the oil pressure line/fittings being you said oil is hitting the fan.
    In order for oil to shoot forward it would need to be under pressure.
     
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  6. BrianM

    BrianM Active Member

    It is a mechanical gauge with copper tubing. I did not check the line yet for splits.
    The pressure switch for the dummy light looks original and I was afraid to mess with it on the trip in case the plastic disintegrated when I put a wrench on it. I am having issues finding a replacement as mine has 3 wires and most all part store sending units are 1 wire.
    When I was in Louisiana I attempted to tighten up the brass fittings and got 1-3 turns on each of the 3 fittings on the top of the T that goes to mechanical gauge. This was still not tight just firmly snug and thought I found the issue but it still did it on the drive home.
     
  7. BrianM

    BrianM Active Member

    Pics of what I am seeing
     

    Attached Files:

  8. Stage 2 iron

    Stage 2 iron 480 IRON HEAD STAGE 2

    Did you check the front rope seal ?
     
  9. BrianM

    BrianM Active Member

    Haven't dug into it yet, was hoping to pick the brains of the people here and make a list of things to check. I got the ignition fixed on my 95 chevy pickup yesterday and I am picking up a starter for my 08 Tundra tomorrow. Once the Tundra is running and out of my shop I will dig into the Buick. Hopefully this weekend but I have heard the Tundra starter is a real pain and since the shop wanted $1k to change it I am guessing I won't be knocking it out quickly. Also want to find a replacement 3 wire sending unit to have on hand if I should damage the old one.
     
  10. jaystoy

    jaystoy Well-Known Member

    I had almost the same exact situation this spring. I did what Larry said, and cleaned everything! Then say the leak. Was the front timing cover crank seal. The balancer and fan were slinging oil EVERYWHERE! Luckly, I have a TA front cover, so I was able to replace the seal without removing the actual cover. No more leaks. So check your seal
     
  11. Jim Weise

    Jim Weise EFI/DIS 482

    That is usually coming off the harmonic balancer.. it will fling the oil out in a circular pattern like that.

    Go to your local Napa, or other parts store, and have them set you up with florescent oil dye and a UV flashlight.. the dye turns the oil yellow or orange, and makes the leak easy to find. Clean everything off, and run it without driving it.. and look for the leak. I bet you find drips on the front of the oil pan.

    Why it was acting the way it did?

    At the higher rpm, you have more blow by past the rings, which results in more crankcase pressure. And that pressure will push the oil past any seal or gasket that is on the weak side.

    Was a common thing back in the day where there were thousands of these things running around with 100K plus miles on them.

    JW
     
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  12. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

  13. BrianM

    BrianM Active Member

    I was hoping it was something with oil pressure and the sending unit as that is much easier to address. I was afraid it was coming from behind the balancer the way it was slinging around. I have uv light for finding AC leaks, didn't know there was dye for motor oil, will have to find some.
    I hate re-doing oil pan seals, I never seem to get it right the first time, especially if it is in a vehicle.

    Thanks for all the information. I am making my list of stuff to get and things to check. I live out in the country and it is 45min drive to the closest part store so it is no fun to have to stop in the middle of something for an hour and a half to run to the parts store.
    Thanks again Larry for the sending unit link. I had searched quite a few parts listings and none looked correct, but that is the one.
     
  14. Schurkey

    Schurkey Silver Level contributor

    '70 Riviera? Don't they use an electric fuel pump in the tank, like Vega used to, and modern FI cars still do?

    If so, that's probably why your oil sending unit has three terminals--two are a pass-through for the fuel pump. (Some vehicles use the extra two terminals for the electric choke.)

    Some of the three-terminal switches have the two pass-through terminals as normally-open. Some are normally-closed. Be sure you get the right kind.

    DO NOT USE TEFLON/PTFE TAPE to seal any threads on an automobile. Even if it works good and seals the fittings, it shreds when disassembled, and you'll never know if you got all the pieces out.

    Given any choice, I use Loctite/Permatex "PST" as a thread sealer. Teflon based, but with an anaerobic hardener included, so that it doesn't just "dry", it "cures". Fabulous stuff. The easiest-to-source variety around here is 592. There's three other common ones, plus some oddballs all using similar formulas but with differences in cure time, temperature range, and holding strength. Any of 'em are good.

    592 is available at any decent auto-parts store, or Amazon, or a hundred other sources.

    https://www.amazon.com/dp/B0002KKTH...olid=2VLYZKC3HBBDO&psc=1&ref_=lv_ov_lig_dp_it
     
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  15. qak

    qak Well-Known Member

    On a side note congratulations on having such a cool car problems or not making a longer trip like that, care to share some pics of the car?
     
  16. BrianM

    BrianM Active Member

    Update:
    I picked up some UV dye for the oil but before I added it I was checking to see if my UV flashlight still worked and shined it on the motor. Previous owner had apparently already done this to find the oil leak and it looked like an alien had been murdered under the hood and thrown into the fan at high speed. Great.
    What I am seeing is that I have oil leaks everywhere. Valve covers, oil pan, timing cover, oil pump, and maybe even front main, every paper/cork gasket I could see from valve covers down was glowing. I also have a lot of blow by oil in the air filter. (probably close to an ounce over the last 2k miles)
    This motor only has about 4k miles on the refresh. (Bored 30 over, new pistons, bearings, comp 260H cam, timing chain, valve guides/seals, felpro gasket set, have receipts for these from 2011) That being said the previous owner only put about 800 miles on the motor rebuild in the last 10 years the other 3k miles I have put on the motor.
    I had thought that the blow by from the valve cover might have been due to the motor still breaking in but now I am wondering if the PCV system is not working correctly and is causing the oil to seep out everywhere.
    Advice on how to test, clean, or common problem spots for PCV ? Is the PCV valve from NAPA going to be the correct one or do I need to go to one of the Buick specialty parts vendors to get the correct part? Currently it has a piece of what looks like gas line from carb to 90* barb with a small piece of the same line between the 90 and PCV. Plan to order the preformed correct hose from TA next paycheck along with several other items.
    Thanks and as always you all are a great resource of information that I appreciate.
     
  17. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Pull the PCV valve and shake it. It should rattle. If it does, reinstall it and run the engine. Pull the PCV out of the intake manifold grommet. There should be strong vacuum. Cover the inlet with your thumb. The engine should slow down a bit. If it does, the PCV valve is operating correctly.

    I have come to the realization that these engines leak.:) Eventually, they all do to some degree or another.
     
    Last edited: Jan 20, 2022
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  18. Schurkey

    Schurkey Silver Level contributor

    With the engine running at fast idle, there should be some vacuum on the opposite side of the engine from the PCV valve, at the fresh air inlet for the crankcase. Depending on the year of the engine, this could be a hose leading to the air cleaner, or a stand-alone air inlet with filtering mesh in it.

    If there's no vacuum, or actual fumes escaping from the fresh air inlet, the PCV system is faulty...or the engine has excess blow-by.
     
  19. BrianM

    BrianM Active Member

    So I replaced the PCV and that didn't make much of a difference. I have some air flow into the valve cover at idle but just barely enough that I can tell it is breathing in. I ran a compression test and I have between 165 and 180 all the way around. Still waiting for a good day to clean the motor and try the dye test. But it is either leaking around the oil pump gaskets or the crank seal and slinging it to the oil pump as the drips are coming off the oil pump.
    How hard would it be to swap in a TA timing cover and pump assembly? $900ish is quite spendy but it looks like this would address both the crank seal and oil pump in one go and is supposed to have additional oiling benefits.

    Anyone done this install with the motor in the car? How difficult? TA cover/pump assembly worth the asking price? Anything else I need to replace, upgrade, inspect, or service while I am in there if I go this route?
     
  20. Mark Demko

    Mark Demko Well-Known Member

    In the car isn’t bad, it’s a lot of bending over. Drain down the rad. Remove stuff, look at timing chain decide to change it, then decide to do a cam swap, remove intake and valve covers, decide to yank the engine, may as well bore it, high comp pistons, while that’s all out replace the cam bearings, may as well put in a high stall converter for the new cam too:p
     
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