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How often do you replace your timing belt on your V8?

Discussion in '4th Gen 4Runners (2003-2009)' started by Muggsy71, May 13, 2024.

  1. May 13, 2024 at 6:57 AM
    #1
    Muggsy71

    Muggsy71 [OP] New Member

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    I’ve been reading up on this and it says you need to replace it every 90,000 miles. How many people do that? How many don’t? Has anyone ever had one break? Evidently it is catastrophic on this engine if that happens.
     
  2. May 13, 2024 at 7:08 AM
    #2
    Borracho Loco

    Borracho Loco My 4Runner identifies as a Prius!

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    Oooh look, another mod.....
    A timing belt or chain breaking on ANY engine can be catastrophic. It can bend valves, crack cylinders, gouge cylinder walls, etc..

    [​IMG]


    Inspect the belt very closely. If see any signs of cracks or excessive wear, change it. What's worse, spending money to replace it too early, or spending thousands of dollars after it breaks and causes your 4Runner to be worthless?
     
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  3. May 13, 2024 at 7:13 AM
    #3
    backpacker

    backpacker New Member

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    I've always replaced timing belts on schedule in any vehicle that had them. Every person I know that's broken a timing belt ended up having to replace the vehicle because the cost of repair is so high.
     
  4. May 13, 2024 at 7:15 AM
    #4
    JChiz

    JChiz Old Member

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    I replaced the timing belt (including timing belt tensioner bearing, idler bearing, water pump, thermostat, drive belt, and pressure cap) at 95k miles on my 2008 Limited. It gave me "peace of mind" out in the remote areas which is priceless!
     
  5. May 13, 2024 at 7:31 AM
    #5
    gkomo

    gkomo New Member

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    I did not know I was recommended at 90k. Thought it was 100k, with that said when I bought my 4Runner I had no proof the second time it was done so I assumed it went 120k before I had it changed. There was a sticker with 117k on the timing cover, and I bought it at 237k
     
  6. May 13, 2024 at 8:01 AM
    #6
    Thatbassguy

    Thatbassguy New member? Really??

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    Only if it's an "interference" motor, meaning that the valves won't clear the piston when they're open. On a non interference motor, it just stalls out. This happened twice on my Supra. No issues, just an inconvenience.
     
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  7. May 13, 2024 at 8:06 AM
    #7
    Thatbassguy

    Thatbassguy New member? Really??

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    I didn't replace the timing belt on my '03 until somewhere around 240K miles. I definitely don't recommend waiting so long. If the belt breaks, it will be a very expensive repair.

    Here's what the timing belt looked like on my 2UZ when we finally replaced it. I was really pushing my luck!

    IMG_20150501_234401705.jpg


    IMG_20150501_234344409.jpg
     
  8. May 13, 2024 at 8:50 AM
    #8
    Borracho Loco

    Borracho Loco My 4Runner identifies as a Prius!

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    I always knew you were crazy, and now I have proof! You played a very dangerous game, sir.
     
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  9. May 13, 2024 at 8:52 AM
    #9
    icebear

    icebear Recovering Kia Owner

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    Ah, so the true interval is clearly 240,000 miles!

    Jokes aside, I'm sure there's more wiggle room in there than we'd say or expect OP, but it's best to play it safe. I'd personally target 100k if I had to stretch it, I don't think a little more would be that bad but it's not my engine on the line.
     
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  10. May 13, 2024 at 9:19 AM
    #10
    Muggsy71

    Muggsy71 [OP] New Member

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    Did you do that yourself or have it done?
     
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  11. May 13, 2024 at 9:25 AM
    #11
    Muggsy71

    Muggsy71 [OP] New Member

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    Holy hell, I have 434,000 on mine. I wonder what it looks like??
     
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  12. May 13, 2024 at 9:26 AM
    #12
    J.A.

    J.A. New Member

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  13. May 13, 2024 at 9:33 AM
    #13
    Thatbassguy

    Thatbassguy New member? Really??

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    I know you aren't asking me, but I did this with a friend's help. We started on it on a Friday evening and it was done Saturday by midday.

    One interesting challenge was that we needed a chain wrench in order to remove the bolt that holds the harmonic balancer on. It wasn't terribly expensive and I think I found it at an auto parts store.

    I think anyone who is decent at wrenching will be able to get it done themselves. It's just time consuming as there's a lot to take off and reinstall.

    Please post a picture when you finally get to it! I'm a little terrified to think what it looks like personally.
     
  14. May 13, 2024 at 9:36 AM
    #14
    Muggsy71

    Muggsy71 [OP] New Member

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  15. May 13, 2024 at 9:41 AM
    #15
    Thatbassguy

    Thatbassguy New member? Really??

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    With the Supra, it wasn't about trying to play Roulette or anything like that.

    The first time it happened, I was totally clueless. I didn't even know it was a potential issue back then. The second time was about a year later, because a camshaft seal had failed, allowing oil to seep into the timing belt cover. Somehow the oil caused the belt to break down and some of the teeth sheared off.

    In the case of the 4Runner, I did inspect it at around 100K, and it looked brand new. I decided to leave it for the time being and then I just put it off way too long.
     
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  16. May 13, 2024 at 9:41 AM
    #16
    JChiz

    JChiz Old Member

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    As a former mechanic, I do most of my own maintenance, however I decided to have this done by a Toyota mechanic at a non-dealer. It saved me a lot of time and trouble plus their excellent work was warrantied.
     
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  17. May 13, 2024 at 9:46 AM
    #17
    Muggsy71

    Muggsy71 [OP] New Member

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    Thanks for the info. I don’t know if I will ever get to it, currently that 4runner is not running, radiator blew out and engine over heated, but I am really curious as to what it looks like. If I had known the V6’s had a timing chain, I would have went with that. I ended up buying another 03 V8, it has 222,000 on it currently.
     
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  18. May 13, 2024 at 9:47 AM
    #18
    Muggsy71

    Muggsy71 [OP] New Member

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    What is required for inspection?
     
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  19. May 13, 2024 at 9:57 AM
    #19
    Airdam

    Airdam New Member

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    a rounded plastic cover on the drivers side, its easy to pull off. Its like 3 bolts and the cover slips up and out of the way to reveal the belt wrapped over the cam gear.
     
  20. May 13, 2024 at 10:00 AM
    #20
    Thatbassguy

    Thatbassguy New member? Really??

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    What @Airdam said-->

    This
     
  21. May 13, 2024 at 11:43 AM
    #21
    Muggsy71

    Muggsy71 [OP] New Member

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    Great, thanks for the info. I’m gonna check them both this evening.
     
  22. May 13, 2024 at 12:08 PM
    #22
    Borracho Loco

    Borracho Loco My 4Runner identifies as a Prius!

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    I just Googled "What percentage of engines are interference engines?" and found this:

    upload_2024-5-13_14-7-50.png

    The list had all automakers on there, from A to Z, but I just wanted to know about Toyota's. Here's the full list.
     
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  23. May 13, 2024 at 12:49 PM
    #23
    Dillusion

    Dillusion New Member

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    I always err on the side of caution.

    Interference or not why do you want to chance being broke on the side of the road.
     
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  24. May 13, 2024 at 1:44 PM
    #24
    Muggsy71

    Muggsy71 [OP] New Member

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    I could be one of your neighbors. I bought a toyota because I don’t really like to work on cars all the time
     
  25. May 13, 2024 at 1:50 PM
    #25
    Muggsy71

    Muggsy71 [OP] New Member

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    I don’t know much about engines, just the basics. I don’t understand why they have these two types. If I was a designer of an engine, I’d want that SOB bombproof….and there wouldn’t be any timing “belts” and I sure as hell wouldn’t design any engine that would be destroyed if the timing belt broke. Must be a price point issue.
     
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  26. May 13, 2024 at 1:50 PM
    #26
    Muggsy71

    Muggsy71 [OP] New Member

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    I know, I was kidding.
     
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  27. May 13, 2024 at 1:58 PM
    #27
    Muggsy71

    Muggsy71 [OP] New Member

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    Kidding about being your neighbor anyway. I do some maintenance but I know I’m a slacker when it comes to timing belts. I’ve never changed one and Ive never had….I’m gonna stop there, I ain’t going to jinx myself. Haha
     
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  28. May 13, 2024 at 2:25 PM
    #28
    Thatbassguy

    Thatbassguy New member? Really??

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    I think non-interference motors are usually lower compression, which isn't always ideal for performance.

    Also, I'm pretty sure modern engines have all gone back to timing chains.
     
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  29. May 13, 2024 at 2:29 PM
    #29
    Muggsy71

    Muggsy71 [OP] New Member

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    Lol. That’s awesome, 24 years, 1 more and you can put a classic plate on that bad boy. How many miles? I’ll work on smaller stuff, enginewise. I replaced the cam shaft on a honda big red side by side. That was pretty tedious and it only has one cylinder. Everything else usually just needs a new carb put on it. As far as vehicles go, I’ll do the basics but if it gets into the engine or transmission, I’m out.
     
  30. May 13, 2024 at 2:33 PM
    #30
    Muggsy71

    Muggsy71 [OP] New Member

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    Well, that makes sense to me, the lower compression thing. Everything being a little further apart may affect compression. Seems like it would be a good idea to have a timing chain on an interference engine. All that aside, this V8 has impressed the hell out of me.
     
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