1MZ-FE timing belt replacement

We are going to work with Lexus RX300’s three-liter, 24-valve 1MZ-FE engine.

It is necessary to replace two rollers — tensioner and bypass in addition to the belt itself while replacing the timing belt. The automatic belt tensioner is also used on the current engine model and it’s better to replace it.

The pump is also subject to replacement since it is an additional roller and is driven by the reverse, not toothed belt side in gas distribution mechanism. No one would like to have the pump stuck at the most inappropriate moment despite the greater pump resource compared to other rollers, therefore it should be replaced with a new one together with the gasket in the kit.

Here is the timing belt. The package includes a sticker which must contain the date and mileage at the belt replacement moment. Glands — a crankshaft frontal gland (oil pump) and two camshaft seals are required in order to complete the procedure.

It’s possible to replace the mounted units, i.e. power steering’ and generator’s/air conditioning’s belts at own discretion.

Start the procedure with protecting the wing from accidental damage- this requires to close it with appropriate fabric piece.

Fasten the fabric with several fairly strong magnets.

Disconnect the two connectors ground wires, unscrew the cruise control mount drive, remove it to the right and unscrew the mount. Remove the upper bracket and engine mount lever.

Then loosen the alternator belt tension mechanism’ locking bolt and loosen the alternator mounting bolt. Then unscrew the belt tensioner bolt to the extent when the alternator belt can be removed and then remove it. Jack up the car and remove the right front wheel and protective plastic panel, fastened with two bolts, thereby gaining an access to the crankshaft pulley. Carefully set the bolts aside in a suitable place or, if possible, tighten them into place in order to prevent the bolts loosening.

Then weaken the power steering belt tensioner (power steering) bolt, as well as the fastening bolt. Now move the pump up and remove the belt. The following procedure — the crankshaft pulley removal is one of the most difficult in the current process.

The required bolt is tightened by a threaded sealant, therefore an impact wrench with force up to 800 Nm will hardly help. Such options as pulley turning off with a starter or locking the flywheel may cause some issues as well as the need to remove the engine. Therefore, a special Toyota tool is used to keep the crankshaft pulley from spinning, but there is an opportunity to make a similar tool with your own if you don’t have the one. A pipe segment with an outer diameter of 90 mm and a length of 50 mm, as well as a steel strip of 30x5 mm and a length of about 700 mm, two M8 x 60 bolts are required in order to manufacture the stripper.

The manufactured tool is fastened to the pulley with two M8 bolts, the lever rests on the ground and the pulley nut is being unscrewed.

The pulley itself is unscrewed once the pulley nuts have been unscrewed, but it hardly may be completed oneself. Try to void knocking on a pulley with a hammer or remove it with a mounting device since the pulley material is rather fragile. It is possible to remove a stream from a pulley or to chop off its edges while Using a puller, therefore, the tool will be required to be modernized a little while making a full puller out of the device for the pulley fastening. A steel strip 30x5mm with the 90mm length is required for refinement. The nut and bolt sizes are M10 x 70mm. The nut is welded to the strip.

Screw the pulley bolt back, but not completely since it will serve as a prop. Fasten the puller on the pulley and gradually tighten the M10 bolt into the puller, which, will move the pulley while resting.

The bolt was tightened too much, so the fixture had to be strengthened, therefore, don’t pay attention to the pre-fabricated element.

The pulley is removed due to long and hard work. But the most interesting is yet to come.

Unscrew 4 bolts, then remove the lower timing belt cover as well as the belt guide plate from the shaft. Be sure to avoid losing the crankshaft keys!

Then remove the cable box from the brackets, unscrew 5 bolts, remove the upper timing belt cover as well as the generator bracket.

Engine bracket rests on the car body while being fastened with two bolts and a nut, which must be unscrewed.

It’s required to jack up the engine for a few centimeters while using a wide wooden beam and a rubber mat the way to avoid damage to the engine tray in order to pull out the bracket, dressed in studs screwed into the unit.

Install the first cylinder to the top dead center while turning the crankshaft clockwise. This requires to combine the crankshaft sprocket label with the oil pump body label. Check if the labels on the camshaft sprockets are opposite the inner lid labels and turn the crankshaft one more turn, if so. Camshaft labels pictures can be seen at the photo report completion.

Then remove the boot from the belt tensioner and measure the stem departure. The distance from 10 to 10.8 mm should be kept from the tensioner body to the stem edge there should. The tensioner must be cocked by drowning the rod. This will require making a serious effort — at least 100 kg. This can be done in a vice, but the tensioner must always have «stem up» position during cocking. Therefore, slowly push the rod until matching the holes in the rod and body and fix it by inserting a suitable hex key into the hole. Then remove the camshaft sprockets. A special tool is required in order to keep the sprockets from scrolling, but this can be done while using the old timing belt help and a suitable wooden board. For this, Screw the belt to the board while using the self-tapping screws and cut off the board from the edge by an arc according to the sprocket radius.

Sprockets surface damage is excluded since the wood is a soft material. Unscrew 6 bolts and remove the inner metal timing belt cover.

Coolant is drained from the system. Unscrew the upper hairpin, which will require a stud extractor in order to pull out the pump. Unscrew the pump mounting bolts and one nut and then remove the pump. Be careful, the antifreeze residues are likely to flow. Old pump gasket is removed. I.e., pump is removed.

Here is the stud extractor itself.

Wipe the pump seat on the block. Then install the new gasket and fix the new pump. Return the screwed pin to its place.

Then start to change the glands. Be sure to remember the depth the old gland was located at. The easiest way to pull out the old gland is while using red-hot self-tapping screws for drywall. Carefully drive in the screw and twist it a couple of turns in the center of the gland, between the shaft and the body. Pull the gland while using the pliers. Usually it’s enough to use just one screw. Rub the gland seat and shaft. Lubricate the sponge as well as new gland outer edge while using lithium-based grease. The gland can be pressed into place while making efforts with fingers.

Slowly approaching to finish. Install back:

1. the inner metal cover (6 bolts, torque 8.5 Nm),
2. the crankshaft sprocket.

Install the bypass roller torque of 45 Nm.

The picture above contains the tensioner, avoid putting it before the belt installation, the new unstretched belt can’t be worn while having the belt tensioner installed. For the tension roller, the tightening torque is 34 Nm while applying thread sealant. Make sure the rollers rotate freely and the tension roller bracket moves without jamming. Moment 125 Nm install camshaft sprockets. Pay attention to the fact the distant camshaft sprocket is installed with the side-guide outward while the near sprocket is installed inside.

Now start to wear a new timing belt. There are 4 labels (2 labels on the camshafts, a crankshaft label and the pump location label) on the new belt. Strictly observe the belt installation procedure, otherwise it will be a painful process to wear it:

1. The «FR» (front) label with the arrow must look to the «from the engine» side;
2. Combine the dotted label with the crankshaft sprocket label;
3. Get the belt for the pump pulley;
4. Then circle the belt around the camshaft pulley neighbor while aligning the belt label with the sprocket label and fix the belt on the sprocket while using a nylon tie-strap;
5. Now circle the belt around the pulley;
6. Then circle the belt around the camshaft far pulley, while aligning the label on the belt with the label on the sprocket and now fix the belt on the sprocket while using a nylon tie-strap;
7. Now put the belt on the tension roller (the new belt will come tight). Install the belt tensioner (27 Nm) while avoiding to remove the check-stopper. Carefully check the matching tags, especially carefully on the far camshaft. Both mirror and flashlight will be required for this. The photo contains the label on the crankshaft sprocket.

Label located on the camshaft sprocket.

The label on the camshaft sprocket in the mirror.

«Front» pointer. Release the belt tensioner — pull out the check if everything matches. Then wait for some time, once again check the label. Now make two full turns of the crankshaft clockwise and check the labels again. Collect everything in reverse order if all is ok.