What follows is a timing belt replacement guide for Toyota 3.0L V6 motors. To begin start by removing the following parts:

Battery

Engine under cover (IFS skidplate)

Over flow tank (optional, makes it easier to reach radiator bolts)

Fan shroud assembly

Drain engine coolant, remove radiator, and hoses

Ignition wires going over top of engine

Engine fan

Remove power steering, AC and alternator belts

Water inlet top and studs (back two nuts together and turn, put a rag into the bowl to prevent loosing the bolts)

Timing belt cover (large black cover, 11 bolts)

Set crank at TDC #1 (should read 0 degrees and both cam marks should be up, if the cam marks do not line up turn the crank one full turn)

Timing belt tensioner

Fan clutch and bracket

If replacing cam seals remove cam gears

Crank pulley (may be necessary to use a puller after bolts have been removed

Remove lower timing belt cover

Timing belt guide (Notice how this washer is slanted on one side)

Remove old timing belt

Remove crank gear (only if replacing crank seal)

Remove idler pulley

Water pump and thermostat

Idler pulley (don't loose the washer behind the pulley, it's very important)

Notes:

There are two different versions of the idler pulley. The '88 to '93 version has a spring integrated into the idler that acts as a tensioner. Upon reassemble this tensioner needs to be adjusted like a fan belt. On '94 to '95 engines the tensioner is a separate part and is not adjustable.

When changing the timing belt there are a number of other items that should also be considered for repair or replacement. Below are several items that are commonly found in need of replacement. Which items you replace is up to you. Mileage and age of the parts should be considered. Is this the first time the belt has been replaced? If not were any of the other items serviced?

Parts Inspection and service

Water Pump:

Check the water pump by turning the impeller and feeling the seal friction. It should not turn freely. Also look at the seal on the impeller side. If the seal is coming apart then replace. In general the water pump is one of the weaker components of the engine and often fails before the engine does. It's a good idea to replace the water pump especially if this is the second belt replacement for the engine (120,000 miles).

Thermostat:

Check the thermostat by compressing the spring, it should move freely and with out binding. You can also boil the thermostat in water to check the opening temperature. As inexpensive as they are it's not a bad idea to just replace them at this point. It's good idea to always replace the "O" ring.

Idler Pulleys:

There are two idler pulleys, the one around the water outlet and the other lower down and opposite the water pump. Check these to make sure they spin well. The idler pulley next to the water pump is known to fail and is often replaced at each belt change.

Tensioner:

Visually check the tensioner for oil leakage. A faint trace of oil is ok. If oil is leaking out of the tensioner it should be replaced. To test the internal resistance push the piston on the ground. You should not be able to compress it. The piston shaft should extend beyond the housing 10.0 - 10.5mm (.394 - .413 in.)

Cam and Crank Seals:

Properly working seals are important for insuring the life of the replacement belt. If oil is allowed to leak from the crank or cams it will likely damage the belt causing it to fail early. Seriously consider changing these seals to ensure long life from the new belt.

Timing Cover Seals:

The rubber seal around the outside of the front cover is important for keeping derbies from contaminating the belt and idler pulleys. Make sure the rubber seal is in good condition.

Reassembly

Once you have inspected the above parts and obtained the necessary replacements your ready to start reassembling the engine. If you choose to replace the cam and crank seals you can reinstall the gears after replacing these.

Before reinstalling the belt the engine but be set "in time". To do this start by making the crank is in the TDC position and the index mark on the top of the crank gear line up with mark on the engine. Next adjust the cams so that both cam marks are up and lined up with their respective marks. Now your ready to slip on the belt. It's important not to bend the belt more than the radius of the crank gear during handling. Keep oil and water away from the belt.

If you are using a belt that has timing marks on it like the Gates T240 belt used here in this example it may be helpful in verify the timing of the engine. In this case however the belt's crank label was way off from the cam mark.

After all three marks (cams and crank) are all pointed up, slip on the timing belt. Next you can install the tensioner ('94 to '95 models only). When installing the tensioner put the two bolts in as far as possible by hand. Next use a wrench to turn one of the bolts about three turns, then turn the other about the same amount. Alternate back and fourth until both bolts are tight. Turning one bolt all the way may cause the tensioner to bind in it's hole.

Check to make sure the belt is on correctly and that all the marks are still aligned up correctly. Be sure to put the belt guide on with the slant side facing out other wise the belt will be damaged upon startup. Continue assembling the remaining parts in the reverse order of disassembly.

It may be necessary to burp the engine after the cooling system is filled. While the engine is running slowly squeeze and release the upper hose. This works water into the engine. After about 20 minutes of running most of the air should be worked out.