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Replace Oil Drain Pan

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by cgm55082, Jul 13, 2013.

  1. cgm55082

    cgm55082 Junior Member

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    Can anyone provide instructions or tips for replacing the oil pan on a 2006 Prius? I changed the oil on my new-to-me 2006 Prius this morning and the oil drain plug was stripped. I bought and tried installing a self-tapping plug, but it didn't work -- basically destroyed any hope of salvaging the pan. Now my car is stranded, without oil, at my home, which is 40 miles from the nearest dealer. That means I'll be doing the work myself. Just wondering if anyone can provide tips or instructions? The dealership said there isn't a gasket, but a gasket forming substance/sealant used between the drain pan and block. Has anyone used that stuff and, if so, how do you use it? Also, anyone know what the drain pan bolts should be torqued to? Is there a pattern in which they should be tightened? Lastly, once the pan is in place can I immediately fill the car with oil and start driving, or do I need to give the sealant time to dry?

    Lots of questions I know, but any help is really appreciated.
     
  2. Mike500

    Mike500 Senior Member

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    You don't need to replace the oil pan.

    The Prius oil drain plug is M12x1.25.

    Those oversize self-tapping drain plugs don't always work.

    Your best solution is to tap the hole out to the Honda or Mazda drain plug size, which is M14x1.5.

    Get a real tap at M14x1.5 and a M14x1.5 drain plug with gasket, and you'll be fine.

    You can also go with M14x1.25 which is used on BMW.

    Conveniently, a stripped out 12mm hole is the correct size for using a 14mm tap without the need to drill out the hole.
     
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  3. vertex

    vertex Active Member

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  4. Mike500

    Mike500 Senior Member

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    Not to brag, but I am a machinist and technician dealing with aircraft, spacecraft, and mechanical devices for over 50 years.

    I have tried and used the rubber plug. It works for a while.

    The method I have outlined is the "tried and true" procedure, that makes it equivalent to a factory OEM quality repair. The larger diameter actually makes the repair stronger than the original.

    The oil plug screws into a welded nut inside the oil pan. I've seen many of them. It is NOT a case hardened of medium carbon steel nut. It is basically "mild steel." Any standard tap in the correct size will suffice.

    If done right, the job is very very easy. The actual job takes no more than 10-15 minutes. And, the results are as good as a new oil pan and a new plug.


    A Mazda or Honda oil plug will have the same 14mm hex on the head as the Toyota drain plug.
     
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  5. vertex

    vertex Active Member

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    I agree with your repair method, I think it is a good input. If you have the tap and can get the new plug quickly, it is the way to go, but if not, the rubber plug will get him on the road until the job can be done properly!
     
  6. Mike500

    Mike500 Senior Member

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  7. cgm55082

    cgm55082 Junior Member

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    Thanks for the comments, but the suggestions will not work for me. When I tried installing the self tapping plug, it bent the wall of my oil pan around the hole where the plug screws in and it's now misshaped pretty badly. Besides that, if you drill and tap your oil pan, don't you get metal shavings in it? The bottom line for me is that I need to replace the pan (it's only $70 at the dealership). I'm hoping someone can help me out with how to use the Toyota form-a-gasket sealant and torque specs for the pan bolts. Anyone?
     
  8. The Critic

    The Critic Resident Critic

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    Pay $27 for alldatadiy and it will have the torque specs for the pan bolts. IIRC Toyota specified FIPG for the oil pan, but I think Permatex has a similar product.

    I would think that the alldatadiy instructions for oil pan R&R would state the cure time require for FIPG. Otherwise Permatex would state on their product packaging, the cure time required.


    iPhone ?
     
  9. The Critic

    The Critic Resident Critic

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  10. Patrick Wong

    Patrick Wong DIY Enthusiast

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    There is no prescribed pattern to tighten the 9 bolts and 2 nuts. I would gradually tighten the hardware in steps, following criss-cross patterns that you've probably noticed used with other vehicles. The idea is not to warp the new pan.

    See below, from the Toyota repair manual.

    45. INSTALL OIL PAN SUB-ASSY NO.2
    (a) Apply a continuous bead of seal packing (Diameter 2.5 to
    3.5 mm (0.0984 to 0.1378 in.)) to the oil pan as illustrated.
    Seal packing: Part No. 08826-00080 or equivalent
    NOTICE:
    Remove any oil from the contact surface.
    Install the oil pan within 3 minutes, and tighten the
    bolts within 15 minutes after applying seal packing.
    Do not expose the seal packing to engine oil within 2
    hours of installation.
    (b) Install the oil pan No. 2 with the 9 bolts and 2 nuts.
    Torque: 9.0 N-m (92 kgf-cm, 80 in.-lbf)
    (c) Install a new gasket and oil pan drain plug.
    Torque: 38 N-m (387 kgf-cm, 28 ft-lbf)
     
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  11. uart

    uart Senior Member

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    Probably not a permanent fix, but that design looks like a great idea for a temporary measure to get it back on the road. It would probably still work as a temporary solution, even with the distorted sump.
     
  12. cgm55082

    cgm55082 Junior Member

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    Patrick, thank you so much for weighing in -- I knew I could count on great information from you. That's exactly what I was looking for. I just want to double check that the oil pan bolts and two nuts should be torqued to 6.6 foot pounds (80 inch lbs)? Thanks again. You're a huge asset to this board and your posts have helped me out time and again, most recently replacing my front/rear struts.
     
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  13. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Yes
     
  14. Mike500

    Mike500 Senior Member

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    The current crop of oil pans are not made of the thick 20 gauge steel found in the pre-1980 car engines.

    The are made of thinner high strength steel. The amount of torque needed to use a self-tapping oil plug evidently met with a great deal of resistance. That resistance apparently resulted in the deformation of the sheet metal of the oil pan. Clearly, an experienced technician would not have used a longer wrench and applied more force when met with resistance that deformed the sheet metal.

    The technique of installing the new oil pan correctly will depend on your ability and your experience.

    The most important thing is cleaning the cast aluminum upper oil sump threaded holes and mating surface.

    From my experience, it is absolutely necessary to clean every remaining bit of the old blue RTV silicone off of the mating surface.

    Every bit of the RTV must be removed from the screws and tapped holes. If you don't, driving in the screws may crack the aluminum casting. Silicone, like hydraulic oil might be compressed in the hole with tremendous pressure; pressure which nay be released through a resulting crack.

    The screws are M6x1.0 pitched. In preparing for such an installation, I would carefully scrape out each hole with a small screwdriver.

    Then I would use ether a thread chasing thread restorer or a bottom tap to clean the RTV out on all the threads in the holes.

    I would either buy BRAND NEW screws or clean each and every bolt with a die or a thread restoring die. The nuts and studs are NOT as important.

    Be advised that you will NOT be able to remove ALL of the RTV residue. That's why torque specs using a torque wrench may NOT be a good idea. The torque specs are for BRAND NEW threads with no silicone residue

    The nuts and studs are used to hold the pan in position to aid in installing the bolts. Put them on first, but do not tighten them fully.

    When reinstalling the bolts, use a 10mm 1/4 inch drive socket extension with only your fingers to run all the bolts into the holes but do not tighten until ALL of them are in. If you feel any resistance, you need to back he bolt out and try again. Finally, you need to tighten all of the bolts finger tight.

    Finally, using a spiral pattern and only short 1/4 inch drive ratchet handle, tighten each bolt no more than 90 degrees or 1/4 turn. Starting from any one bolt, check around the pan with the wrench to make sure that no bolt uas been missed.
     
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  15. cgm55082

    cgm55082 Junior Member

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    Thanks for the tips Rude person's. If I were to try drilling and tapping the hole in my existing pan to m14X1.5 like you originally suggested, would that not result in metal shavings in my oil pan? If I were to try doing that, what is the best procedure? Do I simply drill out the hole with a 14mm drill bit, and then screw in a new tap (half turn in, then back a quarter turn...repeat)?
     
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  16. Mike500

    Mike500 Senior Member

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    Lucky you,

    From my machinist chart, the readily available standard US 1/2 inch drill bit is the recommended size for M14 threads in both M14x1.25 and M14x1.50 threads. While I have most all drill sizes, most people don't.

    To minimize steel chips that might get into the oil pan, I'd grease the tap and withdraw to clean it often.

    You probably distorted the sheet metal beyond the small 1/8 inch or less selling area of the washer. So, a new washer will seal.

    To catch any steel shavings that fay get into the oil, install a magnetic grain plug.


    It is really worth a try.
     
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  17. uart

    uart Senior Member

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    Yep, but it wont immediately go anywhere that's harmful. Just follow this procedure.

    1. Drain oil. (Don't change filter!)

    2. Either keep drained oil if you have a nice clean drain tub etc, otherwise have on hand the cheapest supermarket motor oil you can buy.

    3. Tap drain hole (as per Mikes instructions above).

    4. With plug removed, pour some of your used oil through to carry away the swarf.

    5. Install drain plug and pour in the rest of the used oil or a quart or two of the new "cheap nasty" oil. Don't run engine yet.

    6. Drain the oil again. At least 99.9% of the swarf is now gone. The 0.1% remaining will go directly into the oil filter (and not through the engine) when next you drive.

    7. Fill with cheap new oil. Leave old filter in place.

    8. Give it a moderate drive to get the oil up to temperature.

    9. Drain oil and replace filter. Refill with your regular oil choice.
     
  18. Britprius

    Britprius Senior Member

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    While I agree with Uarts method in principle it is the last part that is problematic.
    The oil before it gets to the filter goes through the oil pump. This consists of precision rotors rotating in an aluminium casing with precise gaps.
    Any metal particles going through this will score the aluminium and damage the pump reducing it's output and pressure. Maybe that is the best that can be done in the situation, but something I would not be happy trying.

    John (Britprius)
     
  19. jdcollins5

    jdcollins5 Senior Member

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    If it were mine, I would change the oil pan and not take a chance with tapping the drain plug, especially since you bent the pan.

    The oil pan should not be expensive and the change out is easy.
     
  20. Mike500

    Mike500 Senior Member

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    There's plenty of looseness in an oil pump. Believe me, I used to rebuild Mercedes diesels. Wear is based on the clearance between the tow geared rotors and measured with a feeler gauge. The gears don't rub on the housing.

    Unless the metal is very very fine, it will not pass through the oil pick up screen. If so, it will be picked up in he oil filter.

    I'd run a small magnetic pickup through the oil drain hole.

    Finally, as I said before, a magnetic oil drain plug will pick up most all other steel in the area.