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Help! I am not sure if there is something wrong with my engine

Discussion in 'Gen 2 Prius Technical Discussion' started by GasSaver1, Jul 12, 2009.

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  1. GasSaver1

    GasSaver1 Member

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    I have a 2008 Prius that has everything but the leather package. (NOT TOURING) In the last year, I put a lot of miles on the car (22k) mainly driving back and forth to Florida.

    I am not rough on the car, but I do tend to do the 17-20 hour trip straight through. But I typically cruise at 70-80.

    I do keep everything up to date as in I change the oil every 3k miles with mobile 1 5w30 synthetic, always replce the filter and the crush washer, keep all the air filters up to date, tires at the right pressure ect.

    Now this is going to be really hard to explain..... there is a strange noise that I have not noticed before.
    >It sounds mechanical and is louder the faster I go
    >I do notice it if I have talk radio on an like level 30.
    >It is almost a growling ch-ch-ch-ch, as if something is turning on the engine or transmission.
    >The sound is there if I am coasting too and if I drop it into neutral.
    >It is not the rev of the gas engine if I give it gas.
    >It is not the raw of the factory tires on the road.
    >Sometimes I hear it more like if I have been driving for a while. If I stop for gas I tend not to hear it for a little while.
    >If I am cruising and hear it and gun the gas a little (accelerate) but quickly take my foot off the gas the sound seems to go away until the transmission readjusts itself at which point it starts again.
    >It is not the high "whirl" when you are coming to a stop and the regenerating brake kicks in.
    >The sound is a lower tone and as I tried to describe has a mechanical frequency to it that speeds up as I go faster.
    >I check the info screen when this is happening and it can be at all times: engine giving power to battery and wheels, battery giving power to wheels, engine and battery giving power to wheels, only battery recharging, and coasting in neutral.

    Now my father owns a 2007 and I took that for a drive. I do hear the same sound a little but no where near as loud as mine and it happens in my car more often.

    I am not sure if I can use my father's car as a good test because he had that extra battery installed where the spare tire goes- with the wall plug in- this also requires the suspension to be upgraded for the weight. In short, the car has been modified so might act differently.

    ---

    I really noticed this after this past week but I put 4k miles on the car this week. The sound may also have always been there and I just never noticed or had the radio too high to hear.

    I still avergaed 48mpg at 70-80 (actually I was even at 57mpg while I was stuck in traffic in the city- this is trans NYC-South Florida driving).

    So despite the sound, the car is WORKING........

    So my questions are:
    Is this normal?
    If not, what could it be? engine? transmission? something with the charging system?

    I am rather worried, I would be grateful for any feedback.
     
    #1 GasSaver1, Jul 12, 2009
  2. triumph1

    triumph1 Member

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    That's the sound of an engine chuckling for you running 3000 mile synthetic oil change intervals. j/k :pound:
     
    #2 triumph1, Jul 12, 2009
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I understand that the sound occurs at all times that the car is in motion, regardless of whether you are in N or in D. I also understand that the intensity of the sound (and the frequency?) increases as your speed increases.

    If my understanding is correct, then I would say that the problem is likely to be a wheel bearing or maybe a tiny rock stuck in your front disc caliper. Your car is probably still under the 3 year / 36K mile warranty; if you can demonstrate the noise to your dealer's service writer it would be reasonable to take the car in and let the service dept figure this out. Good luck.
     
    #3 Patrick Wong, Jul 12, 2009
  4. FL_Prius_Driver

    FL_Prius_Driver Senior Member

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    Next time, turn off the air conditioner if that was on. Probably not the cause, but too easy to eliminate if it is on.

    There are two basic rotational frequencies in the drive train, the engine rpm going into the planetary gear and the wheel related rpms after the planetary gear. When you hear it again, try to see if it follows the engine rpm changes or the car speed changes.
     
    #4 FL_Prius_Driver, Jul 12, 2009
  5. GasSaver1

    GasSaver1 Member

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    well it cant be something stuck in the caliper, its not a squeeking or grinding. its like a quick paced: woo-woo-woo-woo that sounds like it is coming from the front someplace. The intensity goes up as speed goes up (if I have it locked at 80mph it will be much louder than at like 40mph) but again it is not ALWAYS there and it is there on my fathers prius (just fainter) he only has 6k miles on his car.

    I am wondering if the prius is just not designed to run for 17 hours straight at like 70-80 without issues

    edit and I know for a fact it is there with the AC off. I was trying to isolate for most of my trip
     
    #5 GasSaver1, Jul 12, 2009
  6. Celtic Blue

    Celtic Blue New Member

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    Side topic: Why change synthetic oil at 3,000 miles when you are doing long distance trips? If you were using dyno oil and doing primarily short trips (few miles per year) a shorter interval might be justified, but what you are describing is a waste of oil, money, and time.

    On topic: I don't see what 17 hours straight run time would have to do with it. According to you the sound is tied to velocity (tire rotations), not the engine.

    First thing I would check is the tires, rotating front to rear. If the sound switches to the rear then you know it is the tire. Second thing I would consider is tire pressure. You indicate you are running stock pressure. It might be worth trying a higher pressure, still within placard limits to see if it alters the sound.

    Other rotating parts that operate at drive line frequency are of course a concern so the bearings and rotor/caliper assemby would be suspects. Demonstrate the noise to a dealer service writer/mechanic. (Ask to borrow one for a few minutes to demonstrate while it is doing it--I've done that before with various vehicles.)
     
    #6 Celtic Blue, Jul 13, 2009
  7. dogfriend

    dogfriend Human - Animal Hybrid

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    I agree - try to confirm or eliminate tire noise as the issue.
     
    #7 dogfriend, Jul 13, 2009
  8. GasSaver1

    GasSaver1 Member

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    Honestly, I do not think it is the tires because between the 1500mile straight trips I had the tires rotated and balanced and I had the sound in both directions. Of course it is one of those things that once you notice- you go crazy over.

    I am hoping this is not a big deal or anything. Searches from before I posted were listing transmissions over heating and what not- I was worried that maybe running the car for so long so fast damaged something due to heat.

    Hmmm let me ask this, because you all have and drive Prius and know your cars well:

    When you are driving (not braking) and taking the engine rev out and the usual roar of the tires on the roar do you ever notice another "sound" from some place around the engine
     
    #8 GasSaver1, Jul 13, 2009
  9. richard schumacher

    richard schumacher shortbus driver

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    If it is a bearing or joint problem it can quickly become dangerous. Take it to a dealer.
     
    #9 richard schumacher, Jul 13, 2009
  10. jayman

    jayman Senior Member

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    Could be a bearing, could be something else. With sealed bearings, a lot of the old tricks to check bearings (Jack up one wheel at a time, wiggle the wheel to see if it feels "loose") are iffy and may not apply

    Compare the noise to another Prius. Get it taken care of. If it is a bearing, they tend to go quickly
     
    #10 jayman, Jul 13, 2009
  11. paprius4030

    paprius4030 My first Prius

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    We routinly use our 08 Prius to go back and forth from Pa. to Fl. Never noticed any weird noises even with 70k on it now. Do you still have the original tires?
     
    #11 paprius4030, Jul 13, 2009
  12. Bear68

    Bear68 Member

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    Hey GasSaver, I will offer my assistance if you are interested... I am in the West Palm Beach area and would have no problem meeting up with you for an extended test drive to attempt to identify the noise you are hearing. If it turns out to be something covered under warranty, I can even help arrange an appointment at my shop to get it taken care of. If not under warranty, I will be happy to offer my two cents worth on getting it straight.

    Send me a PM if you are interested.
     
    #12 Bear68, Jul 13, 2009
    1 person likes this.
  13. snead_c

    snead_c Jam Ma's Car

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    Just read your offer...way to go Bear68 :rockon:
     
    #13 snead_c, Jul 13, 2009
  14. donee

    donee New Member

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    Hi All,

    Tire or bearing are my guesses. At that kinda service both are running hot. If your not running 42/40 PSI on the tires, they might get hot enough to be at risk for internal delamination over a 17 hour trip. My hydroedge tires make that noise, but its not audible, except during low-speed glides from the driver's position. And they have actually gotten quieter with wear.

    It could be a "spun" bearing too. The bearing is pressed in. If it got real hot and froze momentarily, it could have spun in the hub, and ground the hub clearance loose. Now it spins regularily in the hub.

    Of course there are the other usual suspecs. Have you kept up with inspections of CV boots? If a CV joint is dry - their ya go. If that happened at the beginning of one of those trips, the CV joint would be bad bad by the end in hot weather.
     
    #14 donee, Jul 13, 2009
  15. edthefox5

    edthefox5 Senior Member

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    I have the same issue only not as bad on my 07. Its your tires. I just had my fronts re-balanced and they are not doing it as bad but still have the low freq woo woo as you put it. Keep in mind the stock Integritys are really an awful tire. Really poor. Almost as bad as Wrangler RT/S's.

    Lets prove it:

    Drop your tire pressure on all tires to 28 lbs for a test. Take it for a ride. I bet the noise either stops or is much less. BTW, my Prius and alot of other Prius's come delivered with about 28lbs of pressure. Makes for a nice soft quiet ride (until they wear) but mileage will suffer. Good Luck!
     
    #15 edthefox5, Jul 15, 2009
  16. FBear

    FBear Senior Member

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    The sound you demonstrated above sounds like a slightly warped rotor. This would give you a ch-ch-ch sound that would increase with speed. A warped rotor in a Prius would be harder to detect as the mechanical brakes only come into play at lower speed. In a non-hybrid car the mechanical brakes are always in use so when you press them at high speed you get both a vibration and pulsing in the brake pedal due to the warp in the rotor, no matter how slight the warp. Since the mechanical brake are only used at low speeds (i.e. 7 mph and lower & in emergency situations) the vibration and pulse would be very hard to feel at that low speed. Take the car to a mechanic,put it on the lift with someone in the drivers seat, have him remove the front wheels, the driver should put the car in drive and accelerate slowly. You should both see wiggle of the rotor and hear the noise you describe, if this is your problem.
     
    #16 FBear, Jul 15, 2009
  17. GasSaver1

    GasSaver1 Member

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    The thing is.....
    I do not hear the sound until I have been driving the car for a while. For example, yesterday about 10mins into a drive I started hearing it. It almost sounds like the charging system.

    Now, I should mention that prior to my trip, i DID have my car inspected in new york. (I am a ny resident and keeping the car ny legal). It is a new car, they only had to do safety this year but I do believe that is pulling off a wheel and inspecting a brake. Maybe something happened when they put it back together.

    The next thought. I did the standard tire pressure in ny prior to leaving. 35 psi front 33 psi rear. It was nice and cool at 65ish degrees. Obviously as I moved into Florida things are hotter. Plus the constant motion would have increased the pressure as it is- I am sure my tires are a few PSI over the standard at the moment.

    The only issue I have with these theories is that it would be one thing if the sound was consistent and always there when I jump in the car. The idea that it comes after driving a bit is worrying me. It might have something to do with the battery regeneration. It is not the sharp whirl-down as you come to a stop but it sounds mechanical like an engine turning (not revving up in acceleration).

    It is not a "tick" or "knock". Believe it or not.... I am not new to cars, I owned a 300zx for years and knew all about dirty loud engines. I was able to rip the engine apart and rebuild it ect so I know the "typical" engine problem sounds and this is not one of them. The Prius is still a mystery to me.

    I guess the sound is almost like "something" is working harder than it should be.
     
    #17 GasSaver1, Jul 15, 2009
  18. dogfriend

    dogfriend Human - Animal Hybrid

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    Ah ha ha ha. I had a set of RT/S on my Explorer. Those tires suck. I finally ditched them not because of the tread depth but because I was tired of listening to the roar.
     
    #18 dogfriend, Jul 15, 2009
  19. richard schumacher

    richard schumacher shortbus driver

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    You can see how well this remote diagnosis is working. Take it to a dealer and hope that it's not a bearing or joint problem.
     
    #19 richard schumacher, Jul 15, 2009
  20. GasSaver1

    GasSaver1 Member

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    I want to say a big Thank You to Bear68!!! He met with me today and took a listen to my car. It was just my tires as they start to wear! I feel like a great weight has been lifted from my chest now. I am not sure why I have not noticed this before but I will keep the psi above 35/33 and see if the sound changes. I will also run them close to 44psi all around.

    So again, thanks everyone that replied and especially to Bear68 for meeting with me. That was very nice to do and it is clear he knows what he is talking about! :)
     
    #20 GasSaver1, Jul 22, 2009
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