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YES.......in a millisecond it is a boat anchor. If you are asking this, I assume you are putting off doing a timing belt/water pump job.. Don't if you want to keep your truck a long time....and change everything you can while you're there.
 

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YES.......in a millisecond it is a boat anchor. If you are asking this, I assume you are putting off doing a timing belt/water pump job.. Don't if you want to keep your truck a long time....and change everything you can while you're there.
I just bought it with 154k miles . The belt and water pump was done at 100k according to records. Would like to get another 30k to save up and do it again. Thx for the info.
 

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I just bought it with 154k miles . The belt and water pump was done at 100k according to records. Would like to get another 30k to save up and do it again. Thx for the info.
If you know for sure the belt/pump job was done right, It should be OK. The questions I would have are, Did they change the pump/pulleys, tensioner, etc, and did they use quality parts? There are low quality fake Chinese "kits" being sold as OEM for this job. I found out the hard way and bought one. They look fine if you don't know what they are supposed to look like. I was lucky and found out they were fake before I installed them. Only buy the quality Aisin parts kit and you won't have any nasty surprises in the future.
 

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I see people claim the early 4.7L are interference engines frequently. But I'm not so sure. I have an 02 Sequoia and the timing belt just jumped 180 degrees or more due to a mouse and its nest getting sucked into the crank gear.

Here's the story.... a couple weeks ago my remote starter failed to start the vehicle in the driveway. So I wasn't in it when the problem first occurred and don't know what it sounded like. But it wouldn't start and wouldn't even fire like it wanted to start. I cranked the engine while debugging to be sure it wasn't a spark or fuel problem. I cranked enough to eventually discharge my battery. When I got down to check the timing, the cams were off by about 180 degrees when the crank was at zero. I had just done the timing belt two years and 20k miles ago because it slipped for the same reason but only by a couple of teeth. During that episode 2 years ago, the engine would run like crap and threw codes for misfires. This time the timing was so far off it wouldn't run at all and wouldn't even fire. When I pulled the timing belt and cleaned everything up, I had to reset the cams to zero which meant spinning them 180 degrees while the crank was stationary. I rotated the left cam an extra 360 degrees as a sanity check because the belt lines weren't lining up quite right. Once I got everything back together, the engine runs as good as it did before the problem.

I didn't get a picture of the crank gear when I removed it but the space between the gear teeth were nearly full of compressed mouse guts and nest material. I did get a pic of the gear before I pulled the belt off. I can imagine that the crank gear might have been spinning and the belt not moving at all or continuously slipping because the teeth were riding over the top of all the crap.

So based on this recent experience I'm not convinced the pre-vvti 4.7L are interference designs despite how often I see statements that it is. Now with all that said.... it's still better to replace the timing belt at reasonable intervals. I'm not recommending that anyone wait for it to fail. I'm lucky mine crapped out in the driveway rather than on the road. But I'd wager another 30k on the OP's belt is probably going to be ok.
 

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Not exactly true its the engine would be toast. There's a reason its called the "timing" belt. It has to let go at just the right time, as in one of the valves is open in order to cause damage, so there is always the chance that the belt lets go when the valves are closed. You get those guys who say "well nothing happened so it must not be interference engine". So it is true you can get lucky, but is the risk worth it?
 

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Yes confirmed. The 4.7L engines used in the Tundra, Sequoia and Lexus LX were all interference engines. Timing belts were designed to be changed every 90,000 miles. But many OEM belts do go longer. Toyota starting in 2007 model year, changed all timing belt engines to timing chain engines.

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Sold my 2003 Sequoia with 191k on the clock and the timing belt had never been replaced. I told the new owner and of course adjusted the price accordingly but it just goes to show that a timing belt will go for far more than 90k.
 

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Sold my 2003 Sequoia with 191k on the clock and the timing belt had never been replaced. I told the new owner and of course adjusted the price accordingly but it just goes to show that a timing belt will go for far more than 90k.
I changed mine at just over 90K on my 2001 Tundra just to be safe…and it was in excellent shape! Oh well…peace of mind!😉
 

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Keep in mind that the 4.7L has 2 sets of belts. The visible belt just turns the asssecories and,yep, that definitely needs to be changed before 90k. I'm thinking that 90k on the timing belt is a little aggressive. But if you had to tear into the engine that far to repair the water pump, then hell yeah, do the time belt too. Replacing the water pump is a big job
 

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1st let me say every engine design & recommendation differs between manufacturers on this matter just like what mile to change belts is.

I had an Isuzu for yrs with an interference engine. Some who had a timing belt failure on Isuzu's swore it never hurt a thing on their engine.
Yet others swore it destroyed their engine when theirs failed.
After extensive reading on timing belts I learned most car makers list interference on any engine that "Can" get destroyed when its belt fails.
So lets say 3 out of 10 Toy 4.7 engine's are destroyed when belts fail? Toy says change them all before xxx..

You can gamble?
If it happens maybe you'll be one of the lucky 7, but again you may be one of the unlucky 3 like I'd sure be?

Like mentioned I always worry about what parts were installed last on any used vehicle myself. Way too many junk parts on the market today. I only buy Aisin kits and I always change hyd tensioner every time cause I removed two completely rusted & seized around 100k so not all last 200k like many believe, both cars had oil changed on schedule too.
 
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