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Replace Pistons/Rings vs New Short Block vs Ignore?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by MrPete, Apr 27, 2022.

  1. rjparker

    rjparker Tu Humilde Sirviente

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    Here is a recent video showing an engine removal. Overall a pretty good video on the subject. Link shows potential windshield issues by watching for about one minute.

     
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  2. MrPete

    MrPete Active Member

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    @Tombukt2 -- I have not found a JDM source that can guarantee a 2015 engine. Without that, I guarantee I'm just buying the same issues. I checked P/N's on a few JDM's at the shop... they were just as old as mine :(

    Thanks all... need to talk w/ my mechanic friend. Unfortunately he's also dealing w/ family medical stuff... praying my car can last until there's a window of opportunity.

    Maybe we should make our upcoming Washington State trip into a loop, and return home by way of the SF Bay Area LOL
     
  3. rjparker

    rjparker Tu Humilde Sirviente

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    #23 rjparker, Jul 12, 2022
    Last edited: Jul 12, 2022
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  4. ToyXW

    ToyXW Active Member

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    The longer you drive with a blown head gasket, the more damage you will do to your engine so the less likely it is that you'll be able to use it as a core. Overheating can cause the head and block to warp. Water saturating the cylinder can corrode the cylinder liner and, in extreme cases, cause rods to bend or break (water doesn't compress like air so something else has to give). Coolant mixing with the oil can scour the bearing surfaces...
    Your scope images looked promising in that your cylinder crosshatching still looked pretty good so I bet your engine is currently a candidate for rebuilding, but it currently has a blown head gasket in cylinders 1 & 2 (you can see the carbon on the valves is beginning to flake off from the steam cleaning)

    Used engines are a total crapshoot. Used car dealers have a bad reputation for a reason and used car part dealers are even worse. I just bought a used highlander hybrid engine because the previous owner drove 10,000 miles with overheating issues and cracked the head. Buying a good used engine was an ordeal - and I've done it a few times before! The first engine with "70,000" miles showed up with a VIN number from a car with 170,000 miles (the VIN riveted to the engine did not match the 70,000 VIN on the paperwork). The salvage yard offered to replace it with another "low mile" engine, but said this one had the VIN plate removed... :cautious:

    Ultimately 8 out of the ~10 local junkyards claimed to have <130,000 mile engines, but when I ran the carfax on the VINs they all had odometer readings reported between 150-300K+ As a whole Junkyards lie, so do not believe anything you cannot personally verify. I wound up buying an engine from LKQ and having it shipped from Texas. They had a picture of the car (which had been rear-ended so I didn't have to worry about block damage), the vin, the odometer, etc. All matched carfax records for low miles (and the VIN on the engine actually matched). Still, they said the engine would be here in 5 business days and it took over 2 weeks so I can't quite give glowing reviews for LKQ.

    JDM importers usually have even less documentation. Sure, engines from Japan tend to, on average, have lower mileage. But there are taxi and delivery vehicles in Japan too. The lowest-mile Japanese exports tend to stay in entire cars. The engines tend to come from the rougher cars that aren't worth shipping whole to be sold overseas...

    If you do buy a used engine, don't just throw it in. Replace all of the seals & gaskets while it is out of the car on the engine stand and easy to do. Head gasket, valve stem seals, new timing chain, etc. Ideally you (or your machine shop) rebuilds the head (remove the valves and clean off all the carbon, make sure they seal & recut if necessary, and then measure their tolerances and reinstall them to Toyota specs).
     
    #24 ToyXW, Jul 12, 2022
    Last edited: Jul 12, 2022
  5. Tombukt2

    Tombukt2 Senior Member

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    Yeah anybody who buys another two FX engine is buying into the same problems that they're just getting out of that's a fact but if I'm buying that engine with 65 or 70,000 miles on it I've got 100,000 miles to run that engine generally speaking until the same problems or I get to the near the same mileage that the same problems creep up again and for $2,000 that's not too bad of a deal 2,200 whatever you do of it no problem so mine was around a thousand for the engine if I would have just bought the engine and it been about 500 to put it in I paid three or four more hundred than that because I got a transmission too with the same mileage etc so two grand for a hundred thousand or so miles of driving I don't think that's too bad of a deal you get a gen 4 15 engine Good on you that doesn't guarantee anything is fixed because they made a couple of changes yeah okay. Sounds good but this is happened many times with some of these newer fangled Toyotas you know we've had lots of lots of things going on The Americans have bought them pretty good and now they're a lot of problems just like the American car companies almost That's why I try to stay out of this real new stuff these tacomas and tundras and all this kind of stuff. Go over to the Toyota dealer on a weekend it's worse than the Chevrolet dealership I want to be as far away from that culture as possible
     
  6. Bill Norton

    Bill Norton Senior Member

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    Buddy, Nobody loves a critic....
    However,
    Your posts are troublesome to read because you don't use punctuation marks. With a few of your posts you used the 'Period Key' and those were easier to read!

    Also, you could hit enter at the end of a thought and create a new paragraph.
    I'm just trying to help your readers!(y)
     
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  7. Mendel Leisk

    Mendel Leisk Senior Member

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    He’s apparently voice-dictating and posting without review. Many have commented, for naught.
     
  8. MrPete

    MrPete Active Member

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    Further update.... on the road in WA (yep, 1600+ miles on this trip and another 1600 to get home next week!)
    The HG liquid-fix is holding. Not a single code at any time since Texas, and other than one slight startup hiccup (w/o any banging), it's been smooth.
    And yes, my cylinders appear fine through my new borescope.
    YET: oil still pouring through. 3-4 quarts in 1600 miles. So I DO need a fix.

    I read the older threads on soaks and rings and also valve seals.

    When I get home...now that I understand better
    * I'll do a better look with borescope, to see if the cylinders are actually OK, and also to see if the HG seal has evened up the look of the cylinders.
    * I'll try an extensive soak, to see if that improves oil consumption
    * I expect to at least need to replace the HG sooner than later

    QUESTIONS
    * It appears some people use things like a BG or Liqui Moly product directly in the cylinder as a head soak. Is that right? It does seem marginally safer than using a strong solvent... but also seems less likely to be effective in a soak. Thoughts?
    * I don't find the Cummins Blue Restore product ANYwhere anymore, at any price. Is it still made?
    * I"m thinking the following experiment might be informative before I do a soak: why not try soaking something loaded up with carbon -- say an EGR cooler, or stove-top burner element -- and see if the carbon melts off / falls off / easily comes off? Seems hit or miss to try to test soaks in the cylinder directly ;) Thoughts?
    * Has anyone collected experiences with various soaks in one place on PriusChat? I haven't found anything like that. Just some lists of suggested possible soak fluids.

    Oh, and how far do I have to get into the engine to assess the valve seals?

    THANKS, all!
     
  9. rjparker

    rjparker Tu Humilde Sirviente

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    When the car is burning that much oil plus a confirmed hg leak, it is engine time. The problem on the oil side is the cylinder walls have likely developed uneven wear. There is really no way to repair that on a Prius aluminum block. Even if the cylinder walls are factory and nothing is warped, new pistons and rings are needed.

    In a similar manner, nothing really melts away hard baked carbon, especially while on the engine. The "lucky" direct injection VW owners end up with even more carbon and often resort to walnut blasting with some success. It is expensive and tricky. The Prius egr coolers sometimes need wires as drill bits to plow through.

    I would use your current sealant grace period to line up a rebuilt engine and then go for it. You will still have to ensure your egr and intake systems are cleaned or replaced. With new rings in a rebuild including a head the engine will be reliable for a very long time.
     
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  10. Mendel Leisk

    Mendel Leisk Senior Member

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    Traditionally the head would come off, but IIRC there’s a “rope trick” that’ll prevent the valves dropping. But if you’re doing the head gasket?

    think @rjparker is right; it’s an ex engine.
     
  11. ToyXW

    ToyXW Active Member

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    A brand new shortblock is $1,800 and is going to be superior to any rebuild and far superior to any used engine. A remanufactured head is ~$400-750 (or rebuild your own for half that if you don't mind waiting a few weeks on a machine shop). An overhaul gasket kit is ~$200.

    Optional/recommended: Water pump $200. Engine coolant hoses $80. Inverter water pump $200. Inverter coolant hoses $100. Spark plugs $20.

    Premium refresh: Timing chains & tensioner $300, coils $240
     
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  12. MrPete

    MrPete Active Member

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    I just haven't found a 2015 short block yet. Not now. I've got a line on a $2800 whole engine source, that *may* have 2015+ pistons and rings. If you know of a source, I'm all ears.

    If I'm going to rebuild the head (not just replace HG), isn't that the point where I install new pistons and rings?
    My local dealer will sell me the complete TSB (169?) parts kit for about $800. But I don't have the tools to do the rebuild.

    My EGR and intake were cleaned fully before my earlier TX trip. That's all done.

    I of course will check cylinder walls when I get home. AFAIK they are ok. I do understand that if they're worn, I'm out of luck w/ my current block. :(
     
  13. ToyXW

    ToyXW Active Member

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    You can buy the shortblock from toyota (part number 11400-37140) for ~$1800 from various discount dealers. It is brand new and comes with the latest piston & ring designs.

    The short block is the bottom half of the engine - the block, the cylinder sleeves, the crankshaft, rods, pistons, rings, bearings, etc. You can bolt your existing head on it, but you probably ought to rebuild it first to ensure another 200K miles of trouble-free use. Rebuilding a head basically means cleaning everything and checking tolerances like valve stem diameters against valve guide diameters to make sure the tolerance is not too large (allowing excessive oil to go through). Replace any valves & guides that are out of spec. Make sure the valves are sealing nicely against the seats - regrinding valves/recutting seats if necessary. Replace valve stem seals. Check the deck and cam journals for flatness. Basically the old "valve job" people used to have to do a lot more regularly. Probably cost $150-200 plus any extra parts you might need (e.g. if you can't re-use some of your valves).

    If you didn't want to have you car down for a long time while you wait on backed-up machine shops, you could just buy a rebuilt head assembly from pretty much anywhere. Autozones around here even stock them for ~$650 (with 20% off if you buy online with their coupon code).
     
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  14. Paul E. Highway

    Paul E. Highway Active Member

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    Hey, to get a feel for the short block and head rebuild, have a look at this video. It’s on a 2015 Camry but all the principles are the same as a Prius. Pretty much convinced me to go short block when it’s my turn vs used, JDM or reman. Good info on bore scuffing, oil rings, prepping head, valve guide seals, and so forth.

     
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  15. Mendel Leisk

    Mendel Leisk Senior Member

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    Was watching The Car Care Nut (youtube) unbox a short block for a Camry, and it looks like it stops at the block split-line, roughly 6" above the oil pan flange. I'd suspect the Prius short blocks would be similar. Not a deal breaker. It'd be roughly between the two dashed lines, and as you say, includes crankshaft pistons, all the wear items.

    upload_2022-8-21_9-42-2.png
     
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  16. ToyXW

    ToyXW Active Member

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    Correct - the short block doesn't include the aluminum upper oil pan/windage tray (Toyota calls it "crankcase stiffening assembly") or the steel lower oil pan/sump. Neither of those wear out (unless you let Jiffy Lube impact your drain plug I suppose).

    I'm not sure the prius short block comes with a new oil pump either, but your original oil pump is fine unless you ran low on oil a long time and spun bearings, pumping metal shavings through it.
     
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  17. Krall

    Krall Member

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    What HG repair liquid did you use?

    I haven't kept track of mileage, but after using that stuff on my engine (2nd treatment) I haven't had any issues with shaking. Oil consumption has always been up and down.
     
  18. MrPete

    MrPete Active Member

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  19. MrPete

    MrPete Active Member

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    Unfortunately, CYlinder heads are excluded from coupon codes :(

    But yeah, that combo sounds pretty sweet! $1800+650 -- under $2500 for basically new core engine.
     
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  20. Krall

    Krall Member

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    Thanks Mr Pete! That's what I used. I had to redo it a 2nd time and my mechanic recommended something in a bright green bottle. When I looked there were 4 different ones in that color and the one I picked lasted 5 mins so I redid it with the Bar's.