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Timing Chain Replacement Interval

Discussion in 'Gen II Prius Technical Discussion' started by JeffG, Oct 11, 2006.

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  1. JeffG

    JeffG New Member

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    I called Toyota a little while ago with this question: What is the interval for changing the timing belt?

    It's the wrong question of course since it is a timing belt and not a chain.

    In spite of that, I was given the standard answer of 90,000 miles or 6 years.

    I ain't buying that. Has anyone been able to get an official and realistic answer to this question from Toyota?

    If not, what are your suggestions? I have 115,000 miles on my 2004 and want to believe I don't need to change the chain. Hell, I'm still running on the original brakes.
  2. Beryl Octet

    Beryl Octet New Member

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    <div class='quotetop'>QUOTE(JeffG @ Oct 11 2006, 12:28 PM) [snapback]331184[/snapback]</div>

    I tend to follow the manufacturer's suggestions, I believe this engine is an interference type, i.e., the belt breaks, the valves and pistion attempt to violate one of the laws of physics... I'd go ahead and change it now, unless you are almost ready to sell the car. I'm kidding about that last part, btw.

    <div class='quotetop'>QUOTE(Beryl Octet @ Oct 11 2006, 12:47 PM) [snapback]331194[/snapback]</div>

    I know how to spell piston, but my typing goes to crap after I read the bit about no edits.
  3. ekpolk

    ekpolk The Regenerator

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    <div class='quotetop'>QUOTE(JeffG @ Oct 11 2006, 11:28 AM) [snapback]331184[/snapback]</div>

    Your second line is, I think, backwards. Given your last statement, I'm assuming you're aware it is a chain in the 1NZ. If there's any lingering doubt, here's a snip-out from the first step in the chain replacement procedure:
    [​IMG]

    Since you apparently asked the "belt" question, I'd assess the answer as worthless with respect to a Prius. I wouldn't worry about the chain unless you've got some indication that it's damaged.
  4. JeffG

    JeffG New Member

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    <div class='quotetop'>QUOTE(ekpolk @ Oct 11 2006, 12:42 PM) [snapback]331229[/snapback]</div>

    What indication of damage would there be?
  5. Ari

    Ari New Member

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    I'd be surprised if you ever have to change this part! That's the whole point of a gear or chain driven timing design: it should last the life of the vehicle.

    Dealers like to say something rather than saying "I don't know." When we were shopping for our Honda Odyssey, the sales lady said "... and it doesn't have a timing belt so you never need to change it." That of course is false as I found out when I looked at the maintenance schedule. (apologies to galaxee in advance : not all dealers are shady) B)
  6. FBear

    FBear Senior Member

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    You know the chain is going when you try and do a tune up. Plugs and adjust timing and it runs like cr*p. The chain has probably stretched and skipped a couple of teeth so the engine will run rough.
  7. JeffG

    JeffG New Member

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    Tune up a Prius?

    <div class='quotetop'>QUOTE(FBear @ Oct 11 2006, 12:50 PM) [snapback]331235[/snapback]</div>

  8. ekpolk

    ekpolk The Regenerator

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    <div class='quotetop'>QUOTE(JeffG @ Oct 11 2006, 12:44 PM) [snapback]331230[/snapback]</div>

    Sometimes they will rattle noticeably. This is a common issue with the Nissan/Infiniti VQ series V-6. I owned a G35 that had occasional bouts with rattle on startup. In my case, it was caused by the slight delay in oil pressure to the chain tensioning mechanism. In that context, if it goes away within a couple seconds, it's not indicative of a problem. OTOH, if your chain is stretched (or perhaps it has a damaged link or two), you may hear constant or frequent rattling. In the case of a stretched chain, the rattling is likely the result of the chain tensioning mechanism being unable to keep the now-too-long chain at proper tension.

    All this said, I doubt the 1NZ will have much trouble with its chain, at least I've never heard of this. Chain rattle is one of those things about which there is little mystery when it appears. If you have it, you'll know it. It sounds pretty much like, well, a rattling chain. You won't have to stand there with a technician eying you with that "what asylum did you escape from" look, while you ask, "did you hear that...did you hear that?"
  9. Beryl Octet

    Beryl Octet New Member

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    <div class='quotetop'>QUOTE(ekpolk @ Oct 11 2006, 01:42 PM) [snapback]331229[/snapback]</div>

    Thanks, I just assumed everything had a belt these days.
  10. ekpolk

    ekpolk The Regenerator

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    No sweat. Car makers seem to be drifting back toward the chain designs. Another example is the xGR series V-6s which appear in the 4-Runner/Taco (1GR) and the Camry/Avalon/ES350 (2GR) -- they've gone chain too. I'm guessing that the belt designs created two classes of unhappy customers, those who didn't like the high cost of periodically replacing the belts, and those who didn't like the cost of failing to periodically replace the belts.
  11. hdrygas

    hdrygas New Member

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    <div class='quotetop'>QUOTE(ekpolk @ Oct 11 2006, 11:55 AM) [snapback]331283[/snapback]</div>

    Great answer! LOL :D
  12. Tideland Prius

    Tideland Prius Moderator of the North Staff Member

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    I was under the impression that timing chains were maintenance-free lol. Hmm... But really, if a regular engine needs a tune-up at 100,000 miles...... what about the Prius' engine? 2x that?
  13. Pinto Girl

    Pinto Girl New Member

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    Some engines are designed so that if the timing belt or chain breaks, the pistons and valves will *not* have an unhappy encounter. The Ford 2.3 liter Lima engine (itself forgettable in most other respects) is one example.

    Don't know the engine in our Prii is like that, however.

    Regarding the service life of timing chains...from what I understand, they should last "more or less" the life of the engine.

    But, as the timing chain stretches (even before it jumps a tooth or two) cam timing will begin to go in and out of spec. This may cause some very unusual, and difficult to diagnose, drivability issues, including reduced fuel economy and increased emissions.

    I'd suggest that attending to the timing chain might be one thing to try if the ol' bucket of bolts just isn't running up to snuff.
  14. statultra

    statultra uber-Senior Member

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    i had a chain on a 1985 toyota hilux 22R 4 cylinder, lasted 456,000 miles no problems, i dont really think ill change my chain on my prius until 600000 miles or so, the engine starts and stops half that time anyway
  15. cwerdna

    cwerdna Senior Member

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    <div class='quotetop'>QUOTE(ekpolk @ Oct 11 2006, 11:36 AM) [snapback]331271[/snapback]</div>

    I had a similar (same?) issue w/the same engine (3.5L VQ V6) in my 02 Maxima. They issued a TSB for this http://www.nissanhelp.com/Ownership/Bullet...3/NTB03-060.htm.
  16. dmckinstry

    dmckinstry New Member

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    <div class='quotetop'>QUOTE(ekpolk @ Oct 11 2006, 11:55 AM) [snapback]331283[/snapback]</div>

    Well, in the "good" old days, even with timing chains they would have to be replaced at ~ 60k - 80k miles. Even though the chains were metal, the gear would have nylon teeth, which would break after they got old enough and the chain "stretched" enough. Then the chain would jump a tooth or two, and there'd be no choice but to change the gear and chain.

    Dave M.
  17. BobZ

    BobZ New Member

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    <div class='quotetop'>QUOTE(dmckinstry @ Oct 12 2006, 08:45 AM) [snapback]331627[/snapback]</div>

    Nowadays many timing chain set ups like the three used on Cadillac engines have hydraulic gear tensioners to take up the slack and nylon toothed gears have all but been abandoned ;)
  18. JeffG

    JeffG New Member

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    This is great information, especially because it tells me I don't need spend money.

    Thanks everyone.
  19. Godiva

    Godiva AmeriKan Citizen

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    Uh.....never?
  20. Mia

    Mia New Member

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    <div class='quotetop'>QUOTE(statultra @ Oct 11 2006, 09:42 PM) [snapback]331495[/snapback]</div>

    456,000 miles???? My god, where do you live and drive for that matter.