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Engine oil drain bolt torque spec

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by cycledrum, Nov 19, 2008.

  1. cycledrum

    cycledrum PSOCSOASP

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    http://priuschat.com/forums/care-maintenance-troubleshooting/20794-oil-drain-plug-torque.html

    The thread above says the engine oil drain bolt torque spec is 28 ft-lbs.

    Can anyone confirm this is the Toyota spec for the 14mm drain bolt on the 04 - 09 Prius?

    My 2003 FZ1 motorcycle uses a 17mm drain bolt whose spec is 31 ft-lbs, and we owners feel that is a little high.

    Any comments appreciated. I could always tighten to 20 ft-lbs by feel first and use common sense.
     
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    28 ft.-lb is correct; see attached.
     

    Attached Files:

  3. bc104

    bc104 Junior Member

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    As a former ASE certified master auto mechanic, don't worry about the torque spec on an oil drain plug. Tighten it until it feels tight, but don't crank it until the threads strip.
     
  4. cycledrum

    cycledrum PSOCSOASP

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    Thank you both.

    At Toyota today, I briefly brought torque spec for the drain bolt. Both said, nope, just tighten, but not too tight.

    Now, for the decision of early first oil change, or not. :eek:
     
  5. rumpledoll

    rumpledoll Member

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    If you have a torque wrench, why the heck not tighten to spec? If you don't, I wouldn't go out and buy one for this purpose.

    As far as a pre-5,000 mile oil change, I would leave the factory oil in for the full interval. Not that anyone has brought up any evidence of it being a special "break-in" oil or anything, but neither has anyone shown that modern engines benefit from a quick change out.

    Rumple

     
  6. Patrick Wong

    Patrick Wong DIY Enthusiast

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    On rare occasion we read about a poster who lost their engine when the drain plug came free and oil leaked out. If the mechanics involved were required to utilize a properly-set torque wrench, this would not happen.

    The question of "feel tight" is highly subjective, hence a torque spec is published. Note that the Toyota spec is greater than the spec established on some other vehicles.

    I like using a torque wrench because in the past when I took a more relaxed approach, I found that the subsequent removal of the drain plug took less force than I recalled exerting on the plug during installation - perhaps the drain plug washer compressed while in service. So, by using a torque wrench, there's no need to guess and no need to worry about the plug either coming loose or stripping the oil pan threads.
     
  7. Mr Incredible

    Mr Incredible Chance favors the prepared mind.

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    My first employment out of HS and welding school was working on BIG transformers at Westinghouse in KCMO. Big nuts, big bolts, big wrenches, lots of oompf. It took me decades to get over that indoctrination and no long strip threads and break bolts when working on smaller things. I'm much better now, and use a tq wrench whenever a value presents itself.
     
  8. cycledrum

    cycledrum PSOCSOASP

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    I have 3 torpue wrenches and noted the spec., thank you. I'll bring some wrenches to check fasteners on dealer site after a service.

    I'll be returning the oil and filter to Toyota this morning. Better to follow Toyota recommendations and I have pre-paid maintenance, so no need for oil, filter hanging around the house.
     
  9. narf

    narf Active Member

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    Use the torque spec! The problem is that crushing a new crush washer feels an awful lot like stripping threads. At least a torque wrench can give you the courage to get it tight enough. The penalty for not getting it tight enough could be running the engine dry and either getting stranded or buying a new engine.
     
  10. dogfriend

    dogfriend Human - Animal Hybrid

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    One of my technicians (at my former employer) used to overtighten everything, to the point where I had to stock screw extractors to remove the broken and/or stripped screws from various pieces of equipment.

    On the other hand, I have a tendency not to tighten enough compared to published torque specs; I think this is because I remember what a PITA it was to remove broken exhaust manifold studs from my first vehicle when I was 16 or 17 years old.
     
  11. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Yes, I also recall working on my dad's 1967 Mustang when I was a teen and breaking bolts constantly. In this particular case I think that both the fastener quality and my wrenching technique were suspect. Replacement hardware purchased from Sears was much better quality than the Ford OE hardware.
     
  12. dogfriend

    dogfriend Human - Animal Hybrid

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    Back during the teen years, I didn't even know what a torque wrench was for. I bought the first one after graduating from college. That was also when I started buying quality tools - after rounding off many bolts using cheap sockets.