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Interesting: what's causing an oil leak on a new engine?! ;)

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by MrPete, Mar 17, 2023.

  1. MrPete

    MrPete Active Member

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    Had a wonderful trip to Buena Park, CA to visit Hybrid Pit Stop... who swapped out our 218k mile 2011 engine for their "gold" comprehensive rebuild/upgrade engine, including almost-everything-new (yes, including 2015 pistons and rings)... for US$4500. (The closest deal I found here in CO was in Boulder, for $9000, and no warranty. VS 2 year/24k mile warranty from HPS! My mechanic urged us to do the crazy thing and drive to CA to get it done.

    As recommended, we had a relaxed trip back home, with huge speed variations... three overnights... and a 500 mile oil change in Phoenix, done by an independent cert'd mechanic who told me everything looked great.

    Got home. Not a drop of oil gone. Whew. Engine running and sounding great. Lots of potholes in NM, but that's nothing new. Extreme temp swings in CO (60's to teens), but that's nothing new.

    Last weekend, I noticed an oil puddle under the car. What??!! Losing what appeared to be almost a quart a week, even while sitting in the garage. We've driven about 100 miles since getting home.

    I jacked it up. Oil plug isn't leaking, nor is the new spin-on oil filter.

    I was given a set of things to check... did what I could and found nothing.

    This morning, my mech friend finally had a chance to get it up on his lift. His diagnosis: everything is dry except there's oil below where the lower oil pan connects. A bad oil pan seal??!

    The puzzle: what could have gone wrong?

    I'm told:
    • The engine build was complete well before we even showed up in SoCal
    • Hybrid auto's not seen this before
    My plan:
    • Wipe it down carefully
    • Image all around
    • Use my FLIR to see if I can discover any anomalies before disassembling
    • Carefully disassemble, to maximize opportunity to see any flaw
    I'm curious if anyone here has other ideas on what could have caused it!
     
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  2. Grit

    Grit Senior Member

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    How did you find a shop that sells new gen 3 engine? I want a zero mile new engine myself.
     
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  3. AzusaPrius

    AzusaPrius Senior Member

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    Sorry you are having trouble with your new engine, any pictures taken?

    If its just a simple oil pan leak, then maybe with pictures and communication with Hybrid Pit, they can refund the charge to repair it for you without having to drive back?

    For future customers I would say use my promo code "azusa" on their website and save some cash on it and have it delivered.

    You took a big trip to get a good engine but I do not think it is worth to take the trip back for an oil pan leak.
     
  4. Kenny94945

    Kenny94945 Active Member

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    One quart lost while sitting?
    That's unique, at least to me.

    If I am reading correctly, you have diagnosed it to be the oil pan gasket.
    If not a crack (or hole) in the pan, from all those potholes you mentioned, I would suppose the pan bolts were not tightened, the pan gasket was forgotten/ left off, or the gasket glue/ sealant failed (especially at the corners).

    Easy enough to confirm the bolt torque, which would be my test before disassembly, and that may cure the leak.
    If the gasket was left out, I would hope Hybrid Pit would reimburse; a video of disassembly could be vital evidence.

    Still odd it is losing so much oil while just "sitting" in the garage.
    Let us know the end result.
    Good luck.
     
  5. Mendel Leisk

    Mendel Leisk Senior Member

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    Pan bolt torque is in the repair manual excerpt I posted in OP’s other thread on this.
     
  6. MrPete

    MrPete Active Member

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    Pulled the main under-engine plastic.
    Everything dry above the pan; leak clearly from pan gasket.
    Hybrid PitStop is now reviewing their QA process... because here's what I found:
    • Every other bolt is tight (I'm about to use a high quality older SnapOn torque wrench to check current torque)
    • But the in between bolts easily need more torque
    • And worst of all, when I went to semi-tighten the bolt where the leak is worst... the head came right off
    That tells me that bolt had been tightened at some point w/ an air wrench. A pain waiting to happen.

    Yep, Hybrid PitStop is being great -- they'll reimburse any parts needed.

    My local mech buddy is also awesome. Loaned me his fave low-torque wrench and a $50 set of Mac (lifetime warranty) left-hand extraction screws. With the other parts I just received overnight from Amazon I should be good to go on getting this done.

    BTW, I also learned... Toyota charges around $20 for a tube of their oil pan sealant 029500103. I'll use the Ultra Black. ;)
     
    #6 MrPete, Mar 18, 2023
    Last edited: Mar 18, 2023
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  7. MrPete

    MrPete Active Member

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    UPDATE: The torqued bolts/nuts ranged from 8.5 to 19 ft-lb. Air gunned. And the other ones never had been torqued at all. With it apart, the impact of that is obvious:
    • Where not torqued, oil worked its way through. The seal fell apart. There's oil on the mating edges and just a mess of sealant bits. Useless.
    • Where seriously overtorqued, all of the sealant was squeezed out. Bare clean metal-to-metal with a tiny ridge of sealant along the edges.Yes, not leaking now but who knows how long that would last especially if/when another bolt head pops.
    Hybrid Auto actually mentioned to me while I was visiting that they were hoping to upgrade their operation from outsourcing the block and head operations... to doing more/all in house. This may push them in that direction: their outsource "block shop" obviously got lazy. :(
     
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  8. CR94

    CR94 Senior Member

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    Wow! Apparently they figured if half the bolts are twice as tight as they should be, and the other half are left loose that's perfect, on average?
     
  9. Georgina Rudkus

    Georgina Rudkus Senior Member

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    The initial install of the oil pan has to be either a rookie or lack of attention to detail mistake that is unacceptable quality control.

    I would be also concerned about how and if the technician cleaned out and chased bolt holes in the upper oil pan adapter.

    If the holes were not properly cleaned out and the threads chased, any residue left in the blind hole would act like a hydraulic piston when the bolt is tightened and exert undue pressure in the hole. It would either result in a low tension situation that results in low lock up pressure on the mating surfaces that hold the assembly together.

    At the very worst, the pressure asserted in the blind bolt hole would have nowhere to go except to crack the casting around the bolt hole.
     
  10. ASRDogman

    ASRDogman Senior Member

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    That's very sad. I take it YOU are going to repare it? Hopefully, the screw holes are not
    stripped needed a helicoil....
     
  11. Georgina Rudkus

    Georgina Rudkus Senior Member

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    It's the "goop" or FIP (form in place) gasket material that Toyota uses at the factor. Improperly applied, it fills the screw holes.

    FelPro makes a conventional gasket that does not require hours to cure. To me, that's a better replacement. At the factor, the FIP stuff is cheaper for Toyota when used in bulk.
     
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  12. MrPete

    MrPete Active Member

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    Yep, I'm fixing it, with the experienced help of a mech friend here.

    It's all cleaned up now, and waiting for a full set of new parts to arrive at my local dealership parts counter on Tuesday. Lessons learned / hints from this unusual (?) experience (seems to me not many repairs require pulling the oil pan!)
    • Getting the pan off: not at all easy. I tried several methods. What actually worked, quickly and well:
      • Order an oil pan separator tool. They are all similar, all have similar strengths and weaknesses. I bought the linked one because it was available next-day.
      • (Remove all of the bolts and nuts)
      • Use a flex blade metal putty knife to start. On the leading edge (towards car front) there's an area with flat metal from the engine perfectly aligned, so one can push the knife directly into the seam. Work it until it goes through, then wiggle sideways a bit to grow it.
      • Now hammer (literally) the separator tool into the gap. I was unable to do this without using the putty knife first.
      • Hammer it sideways along the oil pan. It easily stays in the slot with just a little pressure, even around the corners.. I didn't even need the handle most of the time. You'll only get three sides due to the posts in the back corners. That's fine.
      • Now gently pull the pan down with fingers, and pull down/off the two posts. Be Ready: there's still oil in the pan!
    • Cleaning the surface to prep for re-sealing/installing: also not easy until I found a good combo of tools for the job:
      • The bulk of old sealant can be removed with a strong/sharp object. I happen to have lots of woodworking chisels; a one inch chisel worked great! Just be sure it is sharp/smooth. No scratches.
      • Now you've got the remaining stuck-on goop. I tried several less-than-satisfactory things: various scrubbers, solvents (cleaner, brakleen, etc). Too ineffective, easily scratched.
      • What worked great was borrowing a technique I've used (carefully) on our stainless steel gas cooktop:
        • Get a heavy duty (green) scouring pad. About 1/4-3/8 in thick is best. NO sponge. Available cheap at grocery stores. (I have a pack of larger ones for all-purpose use.) Caution! You do NOT want a pad that scratches.
        • Pull out your vibrating multitool (!). Attach either the flex triangle sanding surface, or any other strong flat non-cutting blade (this time I used a triangular rough-sanding blade.)
        • Cut a piece of scouring pad, larger than the multitool blade (you do NOT want the multitool to touch anything directly!)
        • Place the scouring pad on the surface, hold it in place with the multitool blade.
        • Run at a reasonably high vibration level. You'll quickly get the feel: the multitool makes the scouring pad a zillion times more effective! For this task, with this non-abrasive pad, you can press pretty hard except near the bolts.
        • I had the whole surface cleaned off in a few minutes.
      • I did a final cleaning swipe with some Brakleen. (Suggested by mech friend.) That stuff easily removes residue of almost anything from metal. (I tried removing thicker amounts. Not fun: it evaporates very quickly, before it has time to melt the bad stuff. And it is pretty strong/dangerous. Don't want to have a lot of it around!)
    One more hint: I started cleaning up the oil pan, thinking I would reuse it. But then I discovered it was subtly but seriously bent near the hole that had the broken-off (likely overtightened) bolt, which also had the main leak. Hint: a nice way to visualize flatness of a surface is to run a straight laser beam along it, edgewise. I used my laser level beam. Made the unevenness quite obvious!
     
    #12 MrPete, Mar 19, 2023
    Last edited: Mar 19, 2023
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  13. ASRDogman

    ASRDogman Senior Member

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    There are easier ways of getting off, but as long as it worked... (y)
    You just need to be very carefull not to scratch the engine mating surface...
    Leaving 2 nuts/bolts in place, but very loose, so when it pops off, it doesn't fall.

    Whoever attached the pan was trying to be lazy and cheap and hoped tightening it
    would work. NOPE!

    A new pan is best, and new bolts/nuts.

    P.S. Using a brass wired brush, or wheel on a hand grinder, will protect the
    mating surface from scratches....

     
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  14. MrPete

    MrPete Active Member

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    In this case (Prius), FelPro only has a cork gasket. Totally a matter of opinion. My opinion: no thanks. Cork has a more limited lifetime, tends to spread over time, can dry (on the non-wetted surface) and crack, etc etc.

    There are several RTV options, depending on your working speed:
    • Toyota: 5 minute working time
    • Permatex Right Stuff: available in one minute black or 90 minute black
    • Permatex Ultra Black: 24 hour
    I'm going with Ultra Black myself.
     
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  15. MrPete

    MrPete Active Member

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    Dumb (??) question: if using RTV sealant, are small scratches actually a big deal? I would think the RTV would fill in such things. Would be interesting to see testing to demonstrate how much of an imperfection will be fine ;)
     
  16. ASRDogman

    ASRDogman Senior Member

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    The RTV will fill in the small scratches, that's what it's for.
    I'm not a fan of cork gaskets either. Parts store might still have rolls of black
    gasket material that will work. But I'm certain you could find one that is not cork.
    I owuld think the 90 minute version would be best for what you're doing.
    That will give you enough time without having to feel like you're rushed and
    risk making a mistake.
    You can clean up and put your tools away while you're waiting for it to cure.
    Then install the oil and drive the car so the engine will run for 15-20 minutes.
    Then check for leaks.

     
  17. Mendel Leisk

    Mendel Leisk Senior Member

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    Maybe @GregC1979 will weigh in; this is a black mark for them.
     
  18. Georgina Rudkus

    Georgina Rudkus Senior Member

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    Cork is not ideal, but is is quick and easy to replace, if it has to be done again. Not so, with the goop.

    I've replaced oil pan gaskets on small block Chevy's in Camaros. Now, even with gaskets, that's a real job, especially when the engine needs to be lifted to get the oil pan out.
     
  19. GregC1979

    GregC1979 Active Member

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    Grit, we have exactly what you are looking for actually. We have one built, brand new zero mileage. Contact us if you're interested!
     
  20. GregC1979

    GregC1979 Active Member

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    It's a 1 in 500 "mark" and we will make it right with Pete. We've been texting back and forth. It only helps us on quality control moving forward, which then helps all of YOU who buy engines from us later. ;)
     
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