Front of engine oil leak

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by randerson9248, Feb 18, 2015.

  1. randerson9248

    randerson9248 Junior Member

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    I'm working on daughter-in-law's 2005 Prius.

    It has an oil leak at the front of the engine that leaks a few drops of oil a day. There is oil around the front seal, but I can't tell if leaking out of that seal or leaking down from above the seal. The timing pointer tab is wet with oil. The upper part of the engine is dry.

    Is that front seal (the one behind the crank pulley) part of the oil pump?

    Any guesses about the most likely spots on the front of the engine to be leaking oil?
     
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Yes. I would clean off the accumulated oil and then monitor the new oil leak to see if it is coming from the seal itself. That seems most likely since you say the upper part of the engine (i.e., the valve cover) is not leaking.

    You would have to remove the crankshaft damper, then the seal can be removed. See techinfo.toyota.com for factory repair manual info if you decide to DIY replace it.
     
  3. randerson9248

    randerson9248 Junior Member

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    Back to working on this.

    I have the water pump pulley and crank pulley off and can see the front engine area better now.

    There is oil dripping from the lower of the 3 bolts attaching the passenger engine support to the front of the engine.
    What would be the cause of engine oil there? I assume that engine support bolt goes through the front cover and is threaded
    into the engine block, not threaded into the front engine cover. Does that bolt attaching the support normally need any kind of gasket
    or sealant to prevent oil seepage.
     
  4. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Looking at the exploded parts diagram I don't see a gasket for the bolt. To investigate further, I suggest you place a hydraulic floor jack with a piece of 2x4 in the saddle under the engine oil pan to hold up the engine, then remove that passenger-side engine support from the front engine cover and see what happens. Those bolts are torqued to 41 ft.-lb.

    Maybe one of the O-rings sealing the oil pump in the front cover to the engine block is faulty. Or perhaps the front engine cover has a crack in it in the vicinity of the oil pump, thus allowing oil to leak out?

    No oil is leaking out at the crankshaft seal?

    Was the car in a front-end accident at some point in its history?

    While you are looking around, how does the engine coolant pump look? Any coolant leaking out of the weep hole?
     
    #4 Patrick Wong, Feb 26, 2015
    Last edited: Feb 26, 2015
  5. 69shovlhed

    69shovlhed Surly tree hugger

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    might just need to remove the bolt, clean everything up good with brake clean. glob the bolt with sealant and torque it back down.
     
  6. randerson9248

    randerson9248 Junior Member

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    Got the support bracket off the front of the engine. Top and bottom bolts were leaking oil.

    Car was purchased used with salvage title. Front cover has been off the car previously, I see a couple
    of non-oem bolts. But, I don't see any cracks in the cover.

    I'm going to reassemble with sealant on the bolt threads. But, I doubt I will be able to clean the block
    threaded holes that well.

    Any suggestions on what sealant to use on the bolt threads, assuming that the block bolt holes may have
    some oil that I won't be able to clean 100%.
     
  7. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Well, if you seal the bolt threads and do nothing further, I think you are just treating a symptom and not the cause.

    The question is where the oil is coming from. One of the two O-rings between the oil pump and block might be leaking, they have to withstand ~60 psi at high engine speeds. The question is whether you want to ignore the leak which may result in engine lubrication failure, resulting in an engine failure down the line.

    Although it will be painful, I think you need to remove the valve cover, then the front cover so you can see what is going on. You may find damage that was never correctly repaired after the accident.
     
    #7 Patrick Wong, Feb 27, 2015
    Last edited: Feb 28, 2015
  8. randerson9248

    randerson9248 Junior Member

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    Patrick,

    I take it from your post that oil around those bolt holes is not normal. If so, I would like to fix correctly.

    Is removing the valve cover and front cover straight forward? Obvious what bolts to remove? Or do I
    need a repair manual to know what steps to follow.
     
  9. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Oil in that area (or any external surface for that matter) definitely is not normal and that should prompt you to look for its source.

    I suggest you subscribe to techinfo.toyota.com so you can see what is involved, where to apply FIPG sealant, etc. You'll need to purchase new gaskets at minimum. If you find damaged parts then the shopping list will lengthen. Good luck.
     
  10. 69shovlhed

    69shovlhed Surly tree hugger

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    I don't know cause I've never done it, but removing the timing cover is probably a royal pita. if you hose those bolt holes out with brake cleaner spray cans, you should be able to get them clean enough to seal it with yamabond, or Mercedes-benz sealant, there are a few other very good sealants out there. you want to seal the shank and head of the bolt, cause the threads are behind the sealing surface. both yamabond and MB sealant will seal an old Harley, and that's saying something. if the cover has been off, most likely the butcher who did the job just didn't know how to seal it right. one more thing: if the bolts aren't oem, you need to verify they are the correct length. there are too many "techs" out there that figure "it ain't my car" and don't care enough to make certain they are using the right hardware for the job. if it doesn't leak after sealing the bolts, you're probably fine. if it does continue to leak, then you must remove the timing cover. I admit I'm lazy, so I would try to seal the bolts before I took the engine apart and ruined a whole weekend or more.
     
  11. randerson9248

    randerson9248 Junior Member

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    Ok.

    Valve cover and timing cover now off. Sealing the bolts would not have helped.

    Timing cover has a crack just above the top motor support bolt. Crack probably happened during whatever event caused the car to be salvage title and crack probably went unnoticed during the rebuilt process.

    Timing cover, two o-ring seals, and valve cover gasket ordered. I don't see anything else needed.

    The timing chain is loose. The chain tensioner appears to be operated by oil pressure. I assume the chain is loose because there is no oil pressure to activate the tensioner. Would this assumption be correct.
     
  12. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I believe the tensioner is spring-loaded and if you find the chain is loose, I strongly suggest you replace the tensioner while you have the front cover off. Check the factory repair manual for info about how to do that.

    What is the condition of the engine coolant pump? Any weeping at the bearing weep hole?

    I have to wonder what else "went unnoticed" during the repair process. More likely, noticed and ignored. Good luck with your investigations and repairs.
     
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