Timing belts have been around long enough that most of our customers are well aware that they need to be replaced at a scheduled interval. Most are also aware of the catastrophic consequences should they be overlooked and left in service until they fail.
Photos 1 and 2: Remove and cap the power steering line before removing the pump. Some techs prefer leaving the pump in place and removing the pulley to gain access.
This month, we’ll take a look at replacing the belt on the V6 Honda/Acura engine, pointing out some details that may make the next job go easier for you.
The first step in timing belt replacement is selling the job. For many years, the industry standard for belt replacement was 60,000 miles. Those of us with more experience can even remember when 30,000 miles was the norm.
Over the years, the materials and processes used in timing belt manufacturing have allowed Honda to move that interval to 90,000 miles and 105,000 miles. I use the 90,000-mile mark as my signal. As a customer’s vehicle nears this indicator, remind him or her that the belt needs to be replaced.
When pricing the job, don’t overlook additional and necessary related sales. The timing belt drives the water pump on these engines. Although very reliable, I would consider it a bad bet to think the pump will last 180,000 miles. The same thing goes for the drive belts. Be sure to include replacing them as part of the 90,000-mile service on the four-cylinder vehicles; it’s easily overlooked when the car is equipped with a timing chain.
I’ll go through the timing belt replacement steps here, but this is not intended to replace the service information available in your shop. One of the most frustrating things for any shop owner is when techs don’t take advantage of available service information.
1. Get started by disconnecting the battery and removing the accessory drive belt. On power steering-equipped cars, the pump or pulley has to be removed to gain access. Some techs will remove the pulley and leave the pump in place, while others will opt to disconnect power steering lines and remove the pump. Either way will work, but if you opt to pull the lines have some shop rags handy to catch any fluid that escapes to avoid messing up your work area (see Photos 1 and 2).
2. As you remove the belts, spin anything that rotates to ensure the bearings are in good shape, and source any needed parts before reassembly.
Photo 3: Crank holding tool
3. Next, bring cylinder number one up to TDC by lining up the white mark on the crank pulley with the pointer on the front cover. Loosen the crankshaft bolt; this can be a challenge without the proper tool to hold the crankshaft. This hex-shaped tool (see Photo 3) fits inside the crank pulley with an opening that provides access to the crank bolt. With the breaker bar or handle of the tool against the cross member, you can apply the needed loosening torque with a breaker bar and extension (see Photo 4).
Photo 4: Crank tool with breaker bar
4. While you’re there, take a close look at the crank pulley for any signs of wear or separation. It’s not a very common problem, but if you’re ever chasing a report of a noise in the timing belt area, or a slipping belt noise when the belts look good, these pulleys have been known to separate. Look closely with the engine running to see if the outer ring (where the drive belt rides) is running true to the hub. If it’s wobbling, more investigation is warranted.
Crank marks are in line for TDC on cylinder number 1
5. Next, support the engine to remove the right-side engine mount bracket. Remove the dipstick tube if it’s in the way, and the previously loosened crankshaft pulley.
6. Remove the timing belt covers. If the model you’re working on uses a timing guide plate, remove the plate from the front of the crankshaft sprocket, making note that the concave side is facing outward.
7. With the covers removed, be sure you have number one cylinder on TDC. With the lower, outer cover removed, align the dimple on drive pulley with the mark on the oil pump (see Photo 5), while confirming that the cam pulley marks are in line with the marks on the inner covers (see Photos 6 and 7).
Any sign of leakage at either style of tensioner should lead to replacement.
8. Before the belt is removed, your service information will instruct you to hold the tensioner in place to prevent it from extending as the belt is removed. To accomplish this, there is threaded boss provided that lines up with the tensioner pivot arm.
New sealed-style tensioner with installation pin installed.
The bolt to do the job is also provided as one of the L-shaped bolts that secure the battery. Grind a slight point on the bolt and install it only hand-tight. You’re not trying to compress the tensioner, but rather just hold it in place. This step can be a time saver if you’re planning to reinstall the timing belt you’re removing. Since the bolt holds the tensioner in place, it won’t be necessary to remove and retract the tensioner.
Photo 10a: Slowly tighten the vice until the pin can be installed
9. Relieve the tension on the timing belt by loosening the timing belt idler pulley bolt and pulley, and then remove the timing belt. There are two styles of tensioners used on the V6s one is sealed, while the other has a service bolt on the backside. With the tensioner removed, if it’s the sealed unit, slowly apply pressure until the service pin can be installed (see Photos 8, 9 and 10a, and 10b-10c).
Photo 10b: Auto tensioner before removal. Note how far the tensioner has extended to compensate for belt wear.
Photo 10c: Tensioner installed with the pin in place
10. If you have a tensioner with the service bolt, clamp it in the vise by one of the mounting ears with the service bolt facing up. Remove the service bolt and, using a flat-bladed screwdriver in the hole, turn the screwdriver clockwise to retract the tensioner to install the U-shape stopper (retaining) tool (see Photo 11). Take care to prevent spilling the oil.
Photo 11: Manual tensioner and stopper tool
Note: If either style of tensioner shows any signs of leakage, it should be replaced. Neither one is very expensive and always keep in mind that the client is expecting this job to hold up for 100,000 miles.
11. With the belt removed, you can now remove the fasteners and replace the water pump. Before you do, don’t forget that you removed the dipstick tube, so if you didn’t seal the hole before, now is the time to be sure you don’t allow coolant to enter the crankcase. Either temporarily install the tube or find a plug that will do the job. An unopened witch’s hat from a bottle of gear oil or tube of silicone will do the job.
12. When it comes time to install the timing belt, reinstall the tensioner with the pin or stopper tool in place, loosely install the idler pulley using thread locker, and then install the timing belt in a counterclockwise direction following this sequence: Crankshaft pulley, idler pulley, front camshaft pulley, water pump pulley, rear camshaft pulley and tension adjust pulley.
Note: Be sure the crankshaft and camshaft pulleys remained aligned with the marks on the back cover. To aid in this process, we use spring-loaded clips to hold the belts on the pulleys as the belt is routed. With the belt in place, tighten the idler pulley bolt to 38 ft.-lbs.
13. Next, remove the retaining tool or pin from the auto-tensioner. Install the engine mount bracket to the front of engine. If you have a timing belt guide plate, install it with the concave surface facing out. Install the lower cover and crankshaft pulley.
14. Lubricate the pulley bolt and tighten to the proper torque; most go to 181 ft.-lbs., with certain models using a torque-to-yield-type bolt (but you would have seen that in your service information before you started this job).
Photo 12: This simple tool makes filling and bleeding the cooling system easy.