Time for new engine?

Discussion in 'Gen 2 Prius Technical Discussion' started by peregrin, Jan 30, 2021.

Page 1 of 2
  1. peregrin

    peregrin Junior Member

    Joined:
    Mar 7, 2013
    28
    9
    0
    Vehicle:
    2007 Prius
    Model:
    IV
    Hi all,

    Our 2007 has 325k, for about 1500 miles the engine has been ticking, apparently the same tick that people report fairly frequently on higher mileage cars that seems to be valve train related. (Top/front of engine) In the last 100 miles, it has become SIGNIFICANTLY louder, with a slight loss in power and a slight occasional surging effect.

    -There is no error code, no MIL/CEL.
    -Oil is checked regularly, changed regularly, with conventional 5w-30 as per the manual. The red triangle of death has never come on in regards to low oil. We have owned the car since 2009, bought with 55k.
    -I removed the Oil Control Valve, not clogged at all.

    I don’t think I want to sell the car, I just replaced the hybrid battery (Newpriusbatteries @2k1Toaster, working great), new tires, new CV axles, new control arms, new struts/shocks, all done recently and before the engine started this nonsense.

    @ChapmanF, @Patrick Wong, @edthefox5 - I’ve read your posts and replies on this subject, time for an engine replacement?

    Everybody, thanks for any and all help.
     
    #1 peregrin, Jan 30, 2021
    Last edited: Jan 30, 2021
    edthefox5 likes this.
  2. Aaron Vitolins

    Aaron Vitolins Senior Member

    Joined:
    Feb 28, 2014
    1,612
    1,144
    0
    Location:
    Franklin TN
    Vehicle:
    Other Hybrid
    Model:
    N/A
    How are your spark plus and oil consumption?
     
    #2 Aaron Vitolins, Jan 30, 2021
  3. peregrin

    peregrin Junior Member

    Joined:
    Mar 7, 2013
    28
    9
    0
    Vehicle:
    2007 Prius
    Model:
    IV
    Spark plugs were fine the last time I checked, always changed at the appropriate intervals (sometimes earlier) with the correct Denso or NGK iridium plugs and torqued correctly. I’ll check them again though.

    Oil consumption is about what is considered normal for a Toyota engine of this era and mileage. It consumes a little, more than it did 250k ago.
     
    #3 peregrin, Jan 30, 2021
  4. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    25,663
    16,763
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    Do you have compression- or leakdown-test results? How's it holding up?

    If you suspect a valve train issue, just taking the valve cover off to see what you see, and even measure the clearances, is not a horrible job, a little worse than a spark plug change. (Doing anything about what you see, that's a horrible job.)

    Those checks could give you some idea how bad anything is really. Maybe it will take you another 100k if you just put up with the noise. Or if you see stuff clearly out of spec, you could choose to replace the engine. Repair/adjustment of the 1NZ valve train is just too fiddly, unless you've got nothing but time.
     
    #4 ChapmanF, Jan 30, 2021
    Mendel Leisk likes this.
  5. peregrin

    peregrin Junior Member

    Joined:
    Mar 7, 2013
    28
    9
    0
    Vehicle:
    2007 Prius
    Model:
    IV
    Just checked the plugs, they seem to be fine. They were tight, not rattling in their sockets. Very little wear, as I changed them not long ago.
     
    #5 peregrin, Jan 30, 2021
  6. peregrin

    peregrin Junior Member

    Joined:
    Mar 7, 2013
    28
    9
    0
    Vehicle:
    2007 Prius
    Model:
    IV

    Hi ChapmanF,

    I don’t have any compression or leak down info handy. A compression loss should result in a noticeable efficiency drop also, yes? We’ve been holding steady at 42-44 at highway speeds for a few years now when there are hills, 46+ when level. This is a bit less than when the car was new. There didn’t seem to be a big change when the ticking got worse, though that was a pretty short distance ago.

    I suppose I really should do a compression test to make sure...
     
    #6 peregrin, Jan 30, 2021
  7. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    25,663
    16,763
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    I can't say how much compression loss translates to how much MPG or what not ... anyway MPG is such an insanely variable real-world measurement I could scarcely suggest how to pick any particular signal out of that noise.

    I just kind of like to combine a leakdown test with each spark plug change. The plugs are out anyway. It's not so much about what any particular test is going to show, as much as what kind of a trend is showing up.
     
    #7 ChapmanF, Jan 30, 2021
  8. PriusCamper

    PriusCamper Senior Member

    Joined:
    Mar 3, 2012
    11,684
    4,730
    0
    Location:
    Pacific Northwest, USA
    Vehicle:
    2007 Prius
    Model:
    Two
    What's it's oil change history? Has it been done by oil change shop that adds oil above the full line? Or have you done it yourself always and kept it more precise? If the former and not the latter your cat could be starting to clog up which can decrease performance.

    Also how's the intake? Have you done air filter, clean MAF sensor and throttle body? I ask because eliminating the performance issue may help determine if the ticking is part of or seperate from the performance problem...
     
    #8 PriusCamper, Jan 30, 2021
  9. peregrin

    peregrin Junior Member

    Joined:
    Mar 7, 2013
    28
    9
    0
    Vehicle:
    2007 Prius
    Model:
    IV
    Hi PriusCamper,

    I have always done the maintenance and have been pretty precise when filling the oil. The intake is clean, I check it regularly (including yesterday) and have cleaned it when necessary, MAF sensor as well (non-chlorinated cleaner), air filter replaced regularly, etc.

    The exhaust system including the cat has been replaced once (by me), both O2 sensors have been replaced also. The exhaust was done about 100-120k ago, both sensors done at the same time, though the upstream sensor has been changed again due to a voltage problem (seemed to be a defect, scanner/Techstream diagnosis).
     
    #9 peregrin, Jan 30, 2021
    PriusCamper likes this.
  10. PriusCamper

    PriusCamper Senior Member

    Joined:
    Mar 3, 2012
    11,684
    4,730
    0
    Location:
    Pacific Northwest, USA
    Vehicle:
    2007 Prius
    Model:
    Two
    Always refreshing to read about a Prius that has been taken such good care of... At this point, maybe it'd be worth experimenting with a different viscosity of synthetic motor oil to see if that changes the sound in any way? There might be some oil additives you could use too, but those can be more problematic than just switching to a full synthetic for older engines that's a bit thicker...
     
    #10 PriusCamper, Jan 30, 2021
  11. peregrin

    peregrin Junior Member

    Joined:
    Mar 7, 2013
    28
    9
    0
    Vehicle:
    2007 Prius
    Model:
    IV
    It’s been a great car, another reason we are not in a hurry to get rid of it. Sure, there’s been the normal maintenance, but I’ve never had a car go 325k with such little fuss. I have a 2008 Civic hybrid with 260k also, and while there are things that Honda does extremely well, the car has been a bit more temperamental than the Prius. (It’s needed three hybrid batteries...the engine is fantastic though.)

    The Prius is due for an oil change about now; I could certainly try a thicker oil and see what happens.
     
    #11 peregrin, Jan 30, 2021
    PriusCamper likes this.
  12. peregrin

    peregrin Junior Member

    Joined:
    Mar 7, 2013
    28
    9
    0
    Vehicle:
    2007 Prius
    Model:
    IV
    Compression update:

    From the left/passenger side -
    Cylinder 1 - 140-150 psi
    Cylinder 2 - 140 psi
    Cylinder 3 - 125 psi
    Cylinder 4 - 125 psi

    All were checked multiple times.
     
    #12 peregrin, Jan 30, 2021
    PriusCamper likes this.
  13. PriusCamper

    PriusCamper Senior Member

    Joined:
    Mar 3, 2012
    11,684
    4,730
    0
    Location:
    Pacific Northwest, USA
    Vehicle:
    2007 Prius
    Model:
    Two
    They make an engine flush you can add before draining the oil... I bought a quart of it once and after reading all the details of what it does I decided to only risk using 1/3 of a quart of it because it seemed like it was designed for big old engines, not tiny little Prius engines.
     
    #13 PriusCamper, Jan 30, 2021
  14. PriusCamper

    PriusCamper Senior Member

    Joined:
    Mar 3, 2012
    11,684
    4,730
    0
    Location:
    Pacific Northwest, USA
    Vehicle:
    2007 Prius
    Model:
    Two
    Maybe it's time to start studying up on piston soak recipes to get #3 and #4 a little healthier?
     
    #14 PriusCamper, Jan 30, 2021
  15. peregrin

    peregrin Junior Member

    Joined:
    Mar 7, 2013
    28
    9
    0
    Vehicle:
    2007 Prius
    Model:
    IV
    A few months ago the tops of the pistons were looking a little dark, I used the Mopar Combustion Chamber Cleaner, definitely made a difference. Cleaned off a ton of the carbon from the top at least.
     
    #15 peregrin, Jan 30, 2021
  16. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    25,663
    16,763
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    One nice thing about a leakdown, rather than compression, tester is that you get to use your ears to figure out where the pressure from cyls 3 and 4 is going. Is there a burned or tight valve? (Hear it in the exhaust or the intake.) Blowing by rings? (Hear it in the crankcase.) Or are 3 and 4 getting friendly and gossiping through the head gasket? (I'm not sure just what sound would give that away, but it is another possibility when two adjacent cylinders have low compression.)

    Normal compression test goes a little too fast and chaotically to make judgments like that (though has its own bag of tricks, like a bit of oil in the cylinder to rule rings in or out).
     
    #16 ChapmanF, Jan 30, 2021
    Mendel Leisk likes this.
  17. peregrin

    peregrin Junior Member

    Joined:
    Mar 7, 2013
    28
    9
    0
    Vehicle:
    2007 Prius
    Model:
    IV
    I agree...unfortunately I don’t have an air compressor to do a leakdown test. I’ll have to check with a local garage.

    I’ve used the oil in the chamber trick before, in my Porsche 914 trying to chase a no-start issue. Completely different car, that one.

    Anyway, would you suggest I look at the valves and lifters first, or have a leakdown test done?
     
    #17 peregrin, Jan 30, 2021
  18. ozmatt

    ozmatt Active Member

    Joined:
    Nov 27, 2015
    596
    250
    0
    Location:
    australia
    Vehicle:
    2010 Prius
    Model:
    One
    Hi :)

    Having a similar issue with an 08 gen2 at the moment, ironically the same mileage (530,000km)

    Getting cold start knock for a couple seconds (most but not all) mornings

    What gets me is there's no codes for engine misfire, this car actually has no trouble codes at all and drives great

    Has pretty bad service history, dirty water in the radiator (no coolant) filthy inside the rocker cover! noisy top end/ lifters

    Starting to wonder if its related to valve set not working properly due to the filthy oil, think i will try a bottle of flush or a quart of diesel in the oil lol, nothing to lose the engine is a real grub!

    :) Cheers
     
    #18 ozmatt, Jan 30, 2021
  19. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    25,663
    16,763
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    I can't think of a powerful argument either way.

    If you would have to go somewhere for a leakdown test, but could peek under the valve cover from home, that might be tempting ... on the other hand, if you don't have a new valve cover gasket handy, you might end up leaky if you reuse the old one, so there might be a "go somewhere" step either way.
     
    #19 ChapmanF, Jan 30, 2021
  20. peregrin

    peregrin Junior Member

    Joined:
    Mar 7, 2013
    28
    9
    0
    Vehicle:
    2007 Prius
    Model:
    IV
    Hmmmm...a valve cover gasket is like $10 from rockauto, I might as well try to look inside there first. If the 3 and 4 valves and lifters are noticeably askew, that may answer the question. We’re not driving the car in this condition anyway.
     
    #20 peregrin, Jan 30, 2021
(You must log in or sign up to post here.)
Page 1 of 2