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Mazda: Timing Belt Replacement

September 1, 2008

It wasn’t too many years ago that broken timing belts were a fairly common occurrence that would naturally lead to belt replacement. But with improvements in belt materials and technology, as well as better informed consumers, timing belt replacements at our shop are now almost exclusively performed as preventive maintenance. This is good news for both the shop and your customer. For the shop, it prevents a surprise job being towed in when your schedule can least absorb it. And there’s never a good time for the customer to experience an on-the-road breakdown, not to mention the potential catastrophic damage that can result from a failed belt.

But like any other maintenance operation, it’s our job to keep the customer informed of when the timing belt should be replaced and why it should be replaced. This month, we’ll be looking at the Mazda line of vehicles, but most manufacturers use similar recommendations. As a general rule, we recommend replacement at 90,000 to 100,000 miles.

At the same time, we always recommend a water pump replacement and a set of drive belts to ensure a job that will deliver another 100,000 miles without having to go under the covers again. While we’ll be looking at the nuts and bolts of a 2002 626 for this article, other Mazda models are similar. And, as always, don’t dive into anything without reviewing service information procedures.

BELT REPLACEMENT TIPS
  1. With the 626 in the bay, the first step is to remove the battery cable, spark plugs, and cam and crank sensors.

  2. Remove the drive belts and move the power steering pump to the side, with hoses attached.

  3. Remove the valve cover and position the engine so the number one cylinder is on top dead center of the compression stroke.

  4. While holding the crankshaft in position with an appropriate tool, remove the crank pulley bolt, the pulley and washer-like guide plate.

    Note: Be careful with the pulley; the crankshaft position sensor rotor is mounted on the rear of the pulley and can be easily damaged if it’s mishandled. If you’re working on a car where the timing belt has failed, it’s not at all uncommon for this rotor or the crank sensor to be damaged by pieces of the broken belt. More than one tech has pulled his hair out with a no-start problem after replacing a broken belt.

  5. With the pulley out of the way, remove the dipstick tube along with the upper and lower belt covers.

  6. Support the engine and remove the right-side engine mount.

  7. Before you go any farther, confirm your timing marks are in the correct location.

  8. Using an Allen wrench, turn the tensioner clockwise to permit removal of the timing belt tensioner spring from its pin on the block.

    Note: It’s important not to be tempted to simply back off the tensioner with the spring attached — that will surely result in stretching the spring beyond its useable tolerance. This engine relies solely on that spring tension to maintain the proper belt tension, so it’s critical that it be in good shape. While they’re available separately — and many timing belt “kits” will include them — there’s no reason to damage the original.

  9. With the spring unhooked, remove the timing belt and check the tensioner and idler pulley for any bearing play or noisy operation that would lead to replacement.

  10. Also be sure that the tensioner pulley moves freely on its pivot so the previously mentioned spring will maintain the proper tension.
CHECK FOR LEAKS PRIOR TO REASSEMBLY
This is the time to take a hard look at the camshaft and crankshaft seals for any sign of leakage that would lead to replacement. Some shops choose to replace seals as part of the recommended maintenance, and that’s certainly not a bad idea. With the belts out of the way, water pump replacement is simply a nuts and bolts procedure.

Reassembly is straightforward, replacing the items removed in the reverse order. Be sure to confirm that the timing marks are aligned, and the tensioner spring is doing its job. It’s always a good idea to turn the engine over a couple of revolutions and be certain the marks return where expected before installing the covers. When filling the cooling system, be sure to fill the radiator or engine, as well as the reservoir, and let the engine warm up until you get good heat in the car, indicating the system is free of air pockets.

V6 PROCEDURE
The procedure for the V6 is very similar with a couple of exceptions that are pointed out in your service info. On this engine, you’ll have to remove the motor mount before the belt covers, and the belt tensioner uses a hydraulic piston rather than the simple spring like on the four cylinders. We should be familiar with the tensioner system and how to service it; don’t use excessive pressure or be in a hurry when pressing the tensioner plunger into its housing, to pin the plunger.

And if there’s any sign of leakage, replace it. Remember, our goal is to give the customer another 100,000 miles of service without repeating this procedure. Like the four-cylinder model, check the idler and tensioner pulleys for noise or play, and be sure the tensioner assembly works smoothly.

On the six, there’s a suggested procedure for belt installation with the goal being to end with some tension between the crank and cams, with the slack on the tensioner side. With the belt in place, install the tensioner plunger, remove the pin and rotate the engine two revolutions. Confirm your timing marks and be sure the plunger extended as expected as specified in your service information system.

CUSTOMER APPRECIATION
As you can see, there’s no reason your shop can’t handle timing belt and water pump replacements on Mazdas. And as it gets harder to keep our bays full with “repair” work, we have to take every opportunity to point out the benefits of preventive maintenance to our customers. Remember, when you recommend needed services, you’re not selling a job, you’re providing the level of service your customers expect and appreciate.


Remanufacturing Is Recycling
Have you considered how your decision to make a major repair to your customers’ vehicle affects our environment?

We’ve researched how much energy Jasper utilizes in the remanufacturing process and compared it with information from the Argonne National Lab, a research center for the U.S. Department of Energy. By averaging the curb weight of three vehicles — a Mercedes-Benz W126, a Hummer H2 and a Toyota Prius — a determination was made on the average amount of energy required in remanufacturing vehicles. Energy usage at Jasper, per drivetrain component, was figured and, on the average, only 1% of the energy is consumed in remanufacturing a drivetrain component in comparison to manufacturing the entire vehicle.

In tangible terms, that’s an energy savings of nearly six tons of coal or 1,008 gallons of crude oil. By purchasing Jasper remanufactured products, rather than replacing their vehicles, our customers saved enough energy in 2007 to power an estimated 598,000 households, or every residence in a city the size of Washington, D.C., for an entire year!

In a still-cited 1981 Massachusetts Institute of Technology study on remanufactured automotive components, it was approximated that 85% of the energy exhausted in the original product was preserved in the remanufactured product. Instead of wasting energy in the replacement of raw materials, Jasper cleans and remanufactures the original castings to the specifications of the OE manufacturer. In another study at the Fraunhofer Institute in Stuttgart, Germany, it was estimated that annual energy savings by remanufacturing worldwide is equivalent to the electricity generated by eight nuclear power plants or 16,000,000 barrels of crude oil — enough to fill 350 oil tankers.

The remanufacturing process breaks the cycle of raw material harvest and production, greatly reducing the emissions of greenhouse gases.

Courtesy of Jasper Engines and Transmissions. Jasper is a recipient of the 2006 Verizon Supplier Excellence Award in recognition of the company’s strengths in environmentally safe remanufacturing techniques. One example is that when drivetrain cores are disassembled, all nonusable metal and aluminum parts (4,057 tons annually) are sent out for reclamation. www.jasperengines.com

 

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