AfterMarketNews Auto Care Pro AutoCareCareerHub Brake&Frontend BodyShopBusiness Counterman EngineBuilder Fleet Equipment ImportCar Motorcycle & Powersports News Servicio Automotriz Shop Owner Tire Review Tech Shop Tomorrow's Tech Underhood Service Speedville

‘Green’ Bullets: Tips for Servicing Hybrid Vehicles

Newsflash: Hybrids are here to stay. The oldest Toyota Prius models are now 14 years old and many other hybrids from other manufacturers are crossing the 100,000-mile mark every day. Here are a few of my Silver Bullets, — or in this case “Green...

Read more...

Legendary Spark Plugs: The Six Toughest Vintage Spark Plug Replacements

1. AMC Pacer: The Pacer was supposed to get a GM Wankel rotary engine. If this were the case, the four plugs would have been easy to access. But thanks to emissions problems, the Pacer would get the regular AMC straight six. This forced the engineers...

Read more...

Battery Service and Diagnosis

A good battery with an adequate charge is absolutely essential for reliable cold starting. A weak battery, or one that is rundown, may not deliver enough amps to crank the engine when temperatures plunge and the oil thickens. Cold weather can be hard...

Read more...

The Problem With Living In The 'Now'

I once had a shop manager who concentrated on the “now.” Every day was a mad dash to complete the jobs at hand. He wanted to know who was working on what, where the parts were and when everything would be done. He was constantly reacting to a customer’s...

Read more...

ASE G1: Drive Belt Inspection, Replacement

The ASE G1 Certification test contains 55 scored questions, plus 10 unscored ­research questions, that cover a range of skills and knowledge related to maintenance and light repairs in engine systems, automatic transmission/transaxle, manual drivetrain...

Read more...

Amateurs and Hacks Provide Job Security For Automotive Service Professionals

Two cars pull up in front of my shop. The drivers didn’t come in, but I heard the commotion from my office window. The boyfriend opens the hood of his girlfriend’s car. They both stare at the engine; she tells the boyfriend that she was supposed...

Read more...

Rotor Failure: Why Rotors Crack and Make Noise

The prices of rotors seem to be dropping the past few years. Call just about any parts supplier and they can quote you a vast range of prices for the same application. And when you compare the rotors side-by-side, they may look the same, but the difference...

Read more...

Wheel Bearings: Measurement and Torque

Wheel bearings are either of the ball or tapered roller variety. Front wheel bearing applications are an angular-type ball bearing, which will accept greater thrust loads than a Conrad-type bearing, and will accept a 100 percent load in the radial...

Read more...

Why Alignment Angles Change

An alignment angle doesn’t change randomly. There is a cause-and-effect relationship between external and ­internal forces that can alter the geometry of a vehicle’s suspension. Having the alignment reading for only one angle on one corner is just...

Read more...

Bendpak Breaks Ground On New Warehouse and Shipping Complex

    BendPak, Inc. announced the recent groundbreaking to celebrate beginning construction of a 67,000 square-foot multipurpose warehouse and shipping center located on 3.7 acres of land in Santa Paula, CA. The new 67,000 square-foot...

Read more...

Pulling Codes: 7 Common Causes of Misfire Codes

A flashing check engine light and a P0301 to P0312 diagnostic trouble code (DTC) is a surefire indication that one or more cylinders are misfiring. Occasional misfires may pass unnoticed, but a steady misfire is hard to miss. The engine usually feels...

Read more...

Analyzing the Cylinder Pressure Waveform from a Running Engine, Part 3

By Vasyl Postolovskyi and Olle Gladso Contributing Writers and Instructors at Riverland Technical and Community College in Albert Lea, MN   In Part 1 of this Maximizing Tools series, we discussed an alternative approach to diagnosing an engine...

Read more...

Home Asian Engine Maintenance: Timing Belt Replacement on Lexus GS 300s

Print Print Email Email

When I think of a “sports sedan” I usually think of the German variety. A BMW 3 or 5 Series, or maybe an Audi Quattro or “E” series Mercedes. Since the early 1990s there has been another choice, but the sales figures have kind of kept these cars a secret. The cars I’m talking about are in the Lexus line of upscale luxury cars, but are either sold as an entry-level car above the ES (fancy Camry), or a step below the flagship LS Series.

The GS and more recently the IS platforms are high-quality, performance luxury models with a conventional front engine, rear-drive or all-wheel-drive layout. Initially, these cars were powered by an in-line six-cylinder from the Toyota Supra line. Later models have gone to V6 and V8 powerplants. Since these cars are somewhat rare (you have to look to spot one on the road), many people would mistake them for their luxury “fluff mobile” cousins in the LS class.

The focus of this article will be the timing belt replacement on a 2001 Lexus GS 300 with the in-line six-cylinder 2JZ-GE engine with VVT-i (Toyota’s variable valve timing). Nothing can spoil the resale value of a high-dollar car more than an engine failure. Due to the complexities of the valve timing and internal engine clearances, these engines will most likely bend valves if the belt fails, or if the belt is installed incorrectly. For these reasons, I would recommend that you read through this article and the service manual description for this job very carefully before starting this repair. There are also differences between models on this platform that can impact the way certain components are removed.

WHEN TO REPLACE
Recommended replacement intervals for timing belts are all over the map these days. Depending on which tech manual or tech assistance site you access, you can get widely varying mileage and time suggestions.

photo 1: it’s difficult to see the dohc in-line 6-cylinder under all of the plastic covers.My advice is to look closely at the accessory belts, note any cracking or evidence of replacement, and then factor in the use of the car and its maintenance history. Cars that are driven primarily in hot, dry climates will probably benefit from earlier replacement than those living in more moderate conditions.

Due to the possibility of engine damage if the belt breaks or jumps time, I would not recommend waiting beyond six years or 90,000 miles, which is the OE-recommended interval for this engine.

A quick scan through service bulletins, tech assistance requests and first-hand experience with this repair leads me to advise that extra care be taken on this repair. Ensure that every step is done correctly, and the proper tools and procedures are used to prevent comebacks, driveability complaints or difficulties in completing this service.

FIRST STEPS
photo 2: color-coding the timing marks will help avoid confusion.Because of the interference possibilities, I suggest removing the ignition key and hiding it so the engine does not get cranked by mistake while the belt is off. The job is easier if it is on a hoist and the lower engine covers are removed. Drain the coolant and remove the fan shrouds.

The various models and yearly changes to this series of cars make an initial inspection worthwhile after checking a repair information source. To prevent the possibility of damage, I would recommend removing the radiator and fan just to provide more working space (see Photo 1). Without removal of the radiator and shroud, space to remove the crankshaft pulley bolt is pretty much non-existent. (On SC 300 models, the battery and battery box will also need to be removed.)

The serpentine belt tensioner may turn either direction depending on model, and the pulley mounting bolt will have threads of one direction or the other, depending on the adjusting rotation of the tensioner. Remove or loosen the brackets for the external accessories (alternator, power steering pump and A/C compressor) as needed to allow removal of the lower front engine cover. Depending on the year, model and body type, some accessories and their brackets are removed or can be left in place to save repair time.

The two upper timing belt covers can now be removed to allow the setting up of the engine for disassembly. Toyota designates these covers as cover 3 (the large piece with VVT-i on it) which looks like the front of a large valve cover, and cover 2, the center part of the front engine cover. If you haven’t already done so, remove the serpentine belt tensioner. Using a suitable tool to hold the crankshaft damper, loosen but don’t remove, the bolt and pulley at this time.

ENGINE SETUP
photo 3: the location of timing marks on the vvt-i sprocket.In order to get the engine in the correct position for removing the timing belt, the tension on the variable timing must be removed to allow the engine to be at actual TDC.

Turn the crankshaft clockwise to align the main timing mark (see Photo 2) on the damper with the “O” mark on the number 1 timing cover (lower part of front cover). There are two marks on the crankshaft pulley and two marks on each of the camshaft sprockets. The main crankshaft timing mark is 60 degrees counterclockwise from the sub-timing mark. The main camshaft timing marks are 30 degrees counterclockwise from the sub-timing marks.

photos 4a & 4b: marks on timing cover 4 (inner timing cover) are difficult to make out without highlighting.Note the location of the camshaft timing marks at this point. On this engine, I recommend that the marks be painted (preferably with different paint colors) to more easily reference the proper marks and locations (see Photo 3), with the hard-to-see marks on the number 4 timing cover (inner timing belt cover, see Photos 4a and 4b). Obviously, if the camshaft marks are not anywhere close, turn the engine another revolution clockwise and start the alignment process again.

Once the main timing marks are located and aligned, turn the crankshaft counterclockwise to align the sub-timing marks (see Photo 5) with the same reference points used for the main timing marks. At this point, if you were planning on reusing the timing belt for some unusual reason, put an arrow on it to indicate the direction of travel. You could also paint reference marks on the belt to speed reinstallation.

While again holding the crankshaft pulley, remove the retaining bolt. A pulley puller may be necessary to remove the pulley without moving the crankshaft. Then remove the lower number 1 timing cover (see Photo 6). Loosen the tensioner (damper) bolts evenly and take the tension off the belt. Remove the outer belt guide (concave side goes out), and the little finger retainer that restricts movement of the belt away from the crank sprocket at the lower right side (5 o’clock position). Then remove the belt after marking the belt and sprocket, if you’re reusing the belt.

INSPECTION
As with all timing belt replacement procedures, inspect for damage to or from the belt, oil leaks or mechanical problems (loose parts) that would shorten the life of the replacement belt. Also, inspect the old belt for cracks, uneven wear, oil or coolant saturation, or impact wear from the guides or foreign objects that might have made their way into the covers. Inspect the tensioner damper for oil leakage that would reduce the tension that it applies.

photo 5: turn the crankshaft counterclockwise to align the sub-timing marks.A small amount of oil may be present at the seal, but nothing more than a little seepage is acceptable. If you can depress the push rod into the housing by hand, replace the tensioner. If the rod does not stick out of the body at least 8.0 to 8.8 mm, replace it. Make sure the tensioner pulley spins freely and that the retaining bolt is tight. Specifications call for Loctite on the retaining bolt and torquing to the proper specification. The pulley bracket should move freely; if not, make sure the spacer washer is in place between the bracket and the engine block on the retaining bolt.

If the camshaft pulleys need to be removed for seal replacement, be aware that to remove the intake variable timing pulley, only the center bolt should be removed. Do not loosen the five bolts that hold the timing mechanism together. If there is any sign of oil leakage at the variable timing sprocket (not the camshaft seal), then the variable timing pulley may need to be replaced. Variable valve timing codes may indicate leakage or other component failure.

photo 6: you may need a puller to get the pulley off without moving the crankshaft.Service bulletins and tech assistance reports indicate that the crankshaft sprocket can be easily damaged, and cause timing and driveability problems and codes. There are reports of even small scratches on the reluctor wheel causing problems as well as missing teeth.

The standard procedure for hydraulic damper retraction is used to depress and pin the damper push rod in a vise or press. Make sure even and straight pressure are applied, and install a 1.5 mm hex wrench or pin to hold the pushrod in the retracted position. The engine should be cold by this time; if not, take a break until it is so the proper tension can be put on the new belt.

BELT INSTALLATION
Photo 7: Make sure the crankshaft is aligned with the mark on the oil pump housing. The crankshaft shouldn’t have moved from its proper position, but double-check and adjust the timing mark alignment on the crank sprocket and the oil pump housing, if necessary (see Photo 7).

Make sure the front of the engine is clean and dry, and slide the new belt onto the crankshaft sprocket and over the idler/tensioner pulley. If you are reusing an old belt, make sure that you have reinstalled it in the same position and direction. Install the little restrictor to hold the belt onto the crank sprocket. Install the lower belt guide onto the crankshaft and install the number 1 timing cover.

Install the crankshaft pulley and make sure that the crankshaft sub-timing mark is still aligned with the “O” on the cover. Install the pulley retaining bolt hand tight (do not move the crankshaft). Recheck the timing marks on the camshafts and adjust if necessary, remembering that the camshaft sub-timing marks should be the ones that are lined up with the marks on the number 4 cover (inner timing cover). Slide the timing belt onto the camshaft sprockets with slack on the tensioner side and no slack between the camshaft sprockets. Install the tensioner damper by alternately tightening the bolts after making sure the dust boot is in position.

Remove the hex wrench or pin from the tensioner body and allow a few minutes for the tensioner to stabilize pressure on the belt. After checking that all the proper timing marks are aligned, turn the engine over by hand, clockwise only, at least two full turns and recheck timing mark alignment. There should not be any restrictions, except the compression of the engine. If it wasn’t such a chore, having the spark plugs out makes this step easier and more conclusive that there is no valve-to-piston contact. If the timing marks are off, redo the procedure rather than take the chance that a mistake was made. Having the marks color-coded makes verifying proper timing easier.

Tighten the crankshaft pulley bolt to the proper torque and reinstall all removed accessories, covers, radiator and fans. Use a vacuum-type cooling system filler to prevent air locks and overheating (not good for a new belt).

FINISHING UP
Even if you haven’t seen or serviced one of these cars yet, they are going to be around for a long time, like most Toyota products. Being prepared for routine maintenance and the peculiarities of the engine and drivetrain will put you ahead of the game when service opportunities come along. These Lexus models are superbly comfortable, extremely well made and performance is on par with the competition. 

The following two tabs change content below.
Latest articles from our other sites:

‘Green’ Bullets: Tips for Servicing Hybrid Vehicles

Newsflash: Hybrids are here to stay. The oldest Toyota Prius models are now 14 years old and many other hybrids from other manufacturers are crossing the 100,000-mile mark every day. Here are a few...More

Legendary Spark Plugs: The Six Toughest Vintage Spark Plug Replacements

1. AMC Pacer: The Pacer was supposed to get a GM Wankel rotary engine. If this were the case, the four plugs would have been easy to access. But thanks to emissions problems, the Pacer would get the regular...More

Timken Launches New Training Material Resources For Automotive Technicians


The Timken Company announces the launch of four new training videos and multiple TechTips focusing on light vehicles during Automotive Aftermarket Week. Timken will reveal all of its new technical training...More

Expanded Walker Direct-Fit Catalytic Converter Line Helping Shops Return To Emissions Segment

A growing number of automotive service providers that have historically outsourced catalytic converter replacement and other emissions control services are returning to the category due in part to the...More

Drift Correction with Cross Camber

One of the common handling-related complaints brought to an alignment shop is ‘drift’ — usually meaning the vehicle fails to continue straight when allowed to choose its own path. Many times, an...More

Independent Rear Suspension Theory

Independent rear suspensions are becoming the norm on cars and SUVs of all sizes. The two main advantages of ­independent rear suspension are ride and handling. When you’re looking up at one of...More

Rotary Lift To Showcase Updated Four-Post Car Lifts At SEMA Show 2014

Vehicle service professionals will have the first opportunity to see Rotary Lift’s updated 14,000-lb. capacity four-post general service and alignment lifts at the SEMA Show. The enhanced lifts will...More

Bendpak Breaks Ground On New Warehouse and Shipping Complex

    BendPak, Inc. announced the recent groundbreaking to celebrate beginning construction of a 67,000 square-foot multipurpose warehouse and shipping center located on 3.7 acres of...More