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Well, I just finished replacing the timing belt on my 2000 Tundra 4.7 with 201,000 miles. Not too hard to do. I read the several excellent posts around here, and printed out the relevant sections of the manual.

Here’s one from another forum: Tundra 4.7 (2uz) Timing Belt & Water Pump Replacement - YotaTech Forums

A lot of details weren’t explained in these posts, so as a detail-oriented person I’ll try to help the next person with my experience. This post will not duplicate those other directions, just refine them.

When buying a replacement serpentine belt, be sure to get one for an engine with A/C - Amazon sells belts for trucks without. :embarrassed3d:

After removal I found that my original serpentine belt tensioner was a bit rough from worn bearings.

I was very pleasantly surprised by how nicely nearly all of the nuts and bolts came off. A far cry from most of the older engines that I have worked on. I washed the engine the day before I did this, to get much of the grime and dirt off the parts I would be handling.

There are two small lines on the bottom of the radiator. These are to cool the transmission fluid. When they come off, a small amount of ATF will come out. Have some newspaper underneath before starting, and a way to block the now four points of oil leakage. I learned that saran wrap held on by rubber bands only works for two days. I probably spilled four tablespoons of ATF total, most on re-assembly.

Taking the fan off was very easy. I just held a blade of the fan near its base and the nuts came right off. To get the fan clutch off was very easy as well. The belt did not grip the clutch pulley tight enough to stop it from spinning when I turned the nuts there, so I just used one hand to grip the pulley with the belt - tightening the belt grip - and that stopped the pulley from rotating enough to loosen the nuts.

I had a fair amount of trouble getting the durn electrical connectors off of the left hand timing cover. The ones that wrap around the wires and then plug into the plastic covers, I found that just pulling them out worked fine, damaging neither the hole nor the fitting. The two longer, tubular ones that hugged a wire were easy as well, a thin screwdriver in a crack and it popped open, freeing the wire. Getting the grey connectors apart took 20 minutes to figure out, but from my O2 sensor experience I remembered that a small flat head screwdriver inserted in the right hole releases the clamp, and the connectors unplug. The connector of the camshaft position sensor would not fit through the hole of the plastic cover because of the black plastic connector that clips onto the grey plug. I never figured out the trick here, and ended up “using a bit of force” and it came off - kicking and screaming - and almost certainly won’t go back on again. . .

To get the left hand cover off, I removed a support bolt on the vertical coolant line support, philips head, so it would move out of the way.

The thermostat cover came right off (I was replacing the thermostat). The thermostat gasket, with 201,000 miles on it, still looked very good and was nice and soft. Still, given the age of the truck, I replaced both the thermostat and the gasket. Remember that the gasket has to be ordered separately (though the Toyota brand one may come with one). No silicone was used on the thermostat cover at the factory, so I wouldn‘t use any either.

Getting the thermostat housing off is a bit of a pain, I have read. I banged it pretty good with a hammer and block of wood, to no avail. There is a tight O-ring fitting on the tube that inserts on the upper passenger side, and the rectangular water pump housing connection to the water pump is siliconed. I rather quickly inserted a very large screwdriver over the rectangular opening, pried down gently but steadily, and it broke free instantly, and then pulled right off. There is a groove in the thermostat housing connection to this rectangular section suggesting an o-ring, and some writeups say o-ring, but there was no o-ring or gasket on my unit - and this was the original water pump. Don’t worry about the short horizontal length of coolant hose that connects to the vertical run. When the assembly is loose it is easy to get to and disconnect.

You have to take off the serpentine tensioner (which I was replacing anyway). To do this, you have to remove the alternator (which will then nestle nicely below on a frame member). To get the alternator off, you need to move the power steering pulley out of the way. Take off the two lower bolts, but just loosen the nut on top. The PS pump will then rotate nicely out of the way. Study and write down whether the tensioner has to be installed before the two covers, or after. On my reassembly the tensioner needed to be installed first, though the manual says after.

One of the toughest things I hit was getting the bottom outside bolt of the fan bracket off, by the A/C compressor. The top bolt might have been easy. Easy to reach with an open end wrench, and once the wire connector is removed, it will come right out But there’s just not enough room to grab the bottom bolt with anything. So, you either disconnect and move the A/C compressor, or (I have read elsewhere) you remove the oil filter. Which means draining the oil then re-filling it. Note that removing the filter helps you not a bit, as I will learn.

I started by trying to remove the A/C compressor. It has just four bolts - Easy! As long as your arms are 37 inches long. . . One with only side access, that you can’t back out very far. You need to remove the wire bracket, which has a Philips head screw. But I got three of the bolts off, and the third backed all of the way out, and that wire bracket off, and the compressor would still just barely move. Huh.

So I drained my oil into a clean container (so I could put it back in the engine). Then started fiddling with the oil filter. And THEN looked at that troublesome bolt. Idiot! There is an easily reached steel compressor support in the way. A bolt (one of the four compressor bolts) and a nut. Then a long extension and 14mm socket and the last fan support bolt comes right off. The A/C compressor moves easily then. The oil filter is in the way of nothing. Well over an hour wasted because I didn’t look at the troublesome thing from below.

The $6 Harbor Freight chain wrench won’t quite fit around the crank pulley - it’s one link too short. I bumped the crank bolt loose with the starter. It came off with the first brief kick, appropriate fuses removed (EFI and Fuel Pump fuse modules) to prevent starting. The risk here is not as obvious as you might think. Sure, it’s easy to get off, but how are you going to torque it back to spec? I used the old-timers’ method of quick sharp raps with a hammer on the socket wrench handle to up the torque on the bolt. As part of the reassembly I used a fair amount of Loctite on the threads. The crank bolt is 22mm, but a 7/8“ socket fits well. I would strongly suggest that you use a ½” socket wrench or a ½” breaker bar for this.

And. . . My pulley puller bolts that should fit in the holes on the crank pulley didn‘t. After wasting an hour on this, I staged a dramatic retreat for the evening. Research on the web says that these bolts should be M8-1.25. Which, after measuring, is what I had. If not, there are a fair number of donor bolts this size that you just removed. So, a nice soak in penetrant on the hole threads, and the bolts screw right in. Rust or dirt was the problem. Stick a big socket in the crank hole, so your puller doesn’t have to go all the way to bottom of the threaded hole. A quick rap with a hammer and it might have come off on its own - with the puller it came off with almost no force. But you should be hesitant to rap the crank in the direction of its plane - as you will want to do. The fit of the crank pulley is so close on the crank that it slides on or off rather slowly. It slid back on, and off, and on very easily.

The old timing belt tensioner has a rubber cap, too. It stayed when I pulled the tensioner out. I had to dig it out with a screwdriver.

Don’t install the timing belt tensioner until the new timing belt is on. Even with the pin in it, it would move the tensioner pulley enough to make putting on the belt extremely difficult. Installed but with the pin still in, the belt was tight enough for the rotation test, and easily removed without consequence if the test fails.

On the rotation test: I will remind you that the marks on the BELT will not line up again, you’re looking for zero on the timing marks and the marks on the camshaft gears to match up with the marks on the head.

As you reinstall the timing belt cover over the crank, don’t forget to put in the small angular plastic timing belt cover spacer. It’s shaped like a triangle with the top corner cut off. No bolts, it just slips in. And if you discover this too late - loosen the two near bolts on the timing belt cover, and it bends enough to allow you to slip the piece in.

The thermostat housing didn’t want to come off, and it also didn’t want to go on. Get a small cup of soapy water and heavily lubricate the new o-ring. Then force it on aggressively. Your goal is to get the o-ring as deep in the well as you can. It took me three tries to do so. I could see a tiny gap on the right side, and a single edge razor blade would slip into the gap, even with both bolts tightened. Banging with a hammer and block of wood didn’t help much if any. Remember that the fancy silicones set up very quickly!

My serpentine tensioner needed to go on before the timing belt covers, though the manual says differently. Best pay attention to these parts when you’re taking them off.

I paid extra to get the Aisin water pump. Just like stock. It is a thing of beauty! And the gasket. . . Oh, man, the gasket. Metal, clad in something slick. And already sealed with a silicone bead. . . The car did not originally have any added silicone here, so I didn’t use any. If your gasket isn’t of such high quality, use your own judgment.

Reassembly requires the use of a torque wrench. Don’t forget to have some Loctite handy.

Since I cheaped out and bought the Permatex Water Pump and Thermostat housing sealer, instead of the pricey Toyota or high end Permatex sealant, I gave the silicone overnight to cure before adding coolant. Eh, to save over $15. And my impression is that the pricier two simply cure faster. I was moving rather slowly anyway.

I had drained the coolant a few days earlier, and re-filled the system from the hose, then drained and re-filled again. A bit of trouble, but I’m changing coolants (to another silica-free brand, not Dexcool). From the block drains, too, with the heater dial set to hot, to get nearly all of the old coolant out. I used a 9” extension and an angle connector for my socket wrench to get the block drains open, and with some tubing this was quick and easy. Actually, since you can get a hand in there to attach the tube, you could also open it with an open end wrench. The drains are brass, one on each side of the block, and have a spout that will hold some tubing to direct the coolant into a bucket. Higher on the block than you’d think, towards the rear. Once you see one, it will be both obvious and easy - just look for the brass. You probably need to lift the front of the truck to do this easily. I drove up on ramps. I drove around a couple of days with just water in the system, then drained the water/coolant in a leisurely manner the night before. No coolant water spilled during the timing belt replacement process.

I don’t think that it’s been mentioned here, but there is an easy way to be sure of a 50-50 coolant mix. If there is only water in the system when the final draining occurs, first add three quarts of pure coolant. In a six quart system like ours, you now know that the mix will be 50-50. Then add distilled water to top off. Mix 50-50 by eye in the overflow tank, up to the middle of the high-low marks.

Since they were both exposed and dirty, I cleaned the Mass Air Flow sensor and the Throttle Body.

A short test drive and. . . WOW! The engine is much smoother, and has more power. Almost certainly the MAF sensor/throttle body cleaning. AND the ticking that has been getting progressively more horrible is gone. It had to be coming from either one of the belts or the failing serpentine tensioner, I think. Not the exhaust manifold. I currently still have the original serpentine belt mounted, but I did remove and re-install it. I’m going to put the gatorback belt on when I get it. And if the ticking returns, I’ll remove the belt and idle the car in the driveway to see if it goes away. This will turn on the check engine light, but I can un-set it.

If I had known the stuff above, and worked straight through, I rekon that the job would have taken me, a handy but non-professional guy, seven or eight hours to do.

Chris
 

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Awesome addition to the existing information. :tu::tu:

I have 97K on my truck and I am leaning towards doing mine myself. Shopping a little for some decent quotes though. So far the best is about $750.00 for the belt and water pump. One shop quoted me $1400.00
 

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Looks like you're in or around Atlanta.... want to help do it again on an 06 DC? I have a friend that's willing to help so you could be more of a supervisor since you've recently done it.

It seems my water pump or what I believe to be the water pump has a slow leak. I figure I'm close enough to the recommended mileage and at about the time range to just go ahead and do the timing belt service. Truck only has ~75k miles on it but I bought it used with 42k less than two years ago and have no idea how well it was treated. It hasn't given me any issues yet but I'd rather keep it that way and do some preventative maintenance.

So what do you say, want to help supervise? I'll buy the beer :)
 

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Discussion Starter #5
Let's see now. How many hours of work - in the Atlanta heat - at my hourly rate, plus travel time to and from, plus gas, plus. . . Man, I'm not sure the Tundra can hold that much beer! :D

Chris
 

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Let's see now. How many hours of work - in the Atlanta heat - at my hourly rate, plus travel time to and from, plus gas, plus. . . Man, I'm not sure the Tundra can hold that much beer! :D

Chris
Understandable. I actually started reading the .pdf and it seems a bit intimidating for me, but only because of the timing pieces of it. Everything else I'm positive I could get through, but I've never played with timing on any vehicle so that part scares me a little.

The hourly rate probably isn't worth my time but I love working on my vehicles and saving that cash would be nice.

If you'd seriously consider helping or supervising, I'd be more than willing to wait a while longer until it cools off..... The house also has a dual kegerator in the bar in the basement :becky:

Where around Atlanta are you? The house is in west Midtown, off the Howell Mill exit.
 

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Discussion Starter #7
I'm near Canton - 45 minutes north of 75/285. The timing part of the job is easy, and clear. Getting the belt on correctly was obvious and easy, and the two rotation test is clear proof that things are set up correctly. Off by a tooth? A minute's work to slip the belt off, move a cam gear a hair with a wrench, and put the belt back on.

Chris
 

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I'm near Canton - 45 minutes north of 75/285. The timing part of the job is easy, and clear. Getting the belt on correctly was obvious and easy, and the two rotation test is clear proof that things are set up correctly. Off by a tooth? A minute's work to slip the belt off, move a cam gear a hair with a wrench, and put the belt back on.

Chris
Maybe I'll just have to go for it. I hope to be doing this in the next month or two so when I do I'll let you know. If you'd like to take a day to come down to the city and supervise while boozing it up, we'll make it happen. :thumb:
 

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I'm desperately hoping to get some help here! Just done my T-belt replacement, waterpump etc, al went well, lined up, good to go. Tried to start it, nothing, just cranking over. Opened again, went over everything, all perfect . Few things I have noticed: 1) I could not hook up a scanner to look for codes, would not connect to computer, 2) The "check Engine light does not come on at all, 3) the 4l & 4H lights are coming on, nothing else. It cranks over just fine, but there is NO spark at all, I have verified by pulling No1 piston Spark Plug, ground it out and cranking it. Please help, my truck sits at someone Else's house, need to get it running, need it daily??

David
 

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Recheck any electrical connections you may have removed and reinserted. Sometimes they won't click all the way in. If all the mechanical stuff went back correctly it seems to me that maybe a harness plug is loose at connection. Reaching here but not sure what else it could be.
 

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Recheck any electrical connections you may have removed and reinserted. Sometimes they won't click all the way in. If all the mechanical stuff went back correctly it seems to me that maybe a harness plug is loose at connection. Reaching here but not sure what else it could be.
Thank you Dino, I'm going to start there. Such a frustration, but part of the deal.
 

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I put a strip of black rubber roofing (bike tube works) then a high grade large hose clamp with hex head on balacer so a piece of wood would go from the clamp head to the frame. You may need to cut hardwood or use a putty knife or such so the wood doesnt split. Works like a charm getting bolt out and in. You can add clamps end to end if too small. Puller bolt holes are actually jacking holes on mine. Just like brake drums. Just keep driving them in evenly. No puller needed. From Pathfinder days, i drew rough sketch of engine front on cardboard and put bolts through to keep the differing lengths where they belong. I dont think it mattered on my 02 4.7.
 
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