Tehachapi's Online Community News & Entertainment Guide

Timing belt replacement service

Helpful tips from Don's Pro Tech Automotive

What to expect from a timing belt replacement service

On the list of engine maintenance items, one of the most important after consistent oil changes is timing belt replacement. For the engine's valves to open and shut at the appropriate times relative to the position of the pistons, a timing belt is used to synchronize the rotation of the crankshaft and camshaft. Unfortunately, timing belt replacement isn't nearly as quick or easy as an oil change, nor is it as low-priced. Regardless, it is necessary to invest in timing belt repair in a timely manner. So, what goes into a timing belt replacement and why is it important?

One thing you need to know is whether your engine has a timing belt or a timing chain. Your owner's manual will have a service interval section. If you have a timing belt, there is an inspection and replacement service interval listed for the timing belt. If nothing is listed, you most likely have a timing chain, which has different service needs, and many times can last the lifetime of the vehicle.

What does it cost to replace timing belt parts?

Timing belt replacement cost varies based on the design of your engine. Typically, the more complicated the engine, the more expensive the timing belt replacement. A single overhead camshaft 8-valve, 4-cylinder engine only has two pulleys to align, one on the crankshaft and one on the cylinder head. A dual-overhead camshaft V8 engine likely has five pulleys that all must perfectly align.

Some engines require special tools to lock the camshafts in place while the timing belt is changed. There is also the issue of what engine components need to be removed to access the timing belt itself. You can also add to it any "might as well do this, too" jobs that the technician should address while the engine is opened, like change the water pump and replace timing belt tensioners.

What if you wait too long to address your repair?

Putting off timing belt replacement is either a bad idea or a downright terrible idea. Most engines with a timing belt require replacement every 60,000 to 100,000 miles (consult your owner's manual for specific mileage). The signs of a bad timing belt are usually sudden and catastrophic.

If you have a non-interference engine and your timing belt breaks, your engine will stop running immediately. You will likely lose power brakes, power steering and all powered motion. If you have an interference engine and your timing belt breaks, you have all the previously mentioned problems plus the likelihood of total destruction of the engine internals. If your engine has an inspection panel, you can look at the belt itself for signs of it going bad. Cracking, fraying and missing teeth are sure signs of a timing belt going bad.

How long does it take to replace a timing belt?

How long it takes to replace a timing belt also highly depends on your engine. The more complex the engine, the longer it will take. A technician can complete a simple timing belt replacement on a simple inline 4-cylinder in less than two hours, while a complicated dual overhead camshaft V8 may take more than eight hours.

How the engine is positioned in the engine compartment makes a difference in how easy it is to access the timing belt. Some vehicles need to be put in "service position," which involves removing large key components like the front bodywork. Engine accessories like the alternator or power steering pump will likely need to be removed.

How to replace a timing belt

The following is a break down of how a timing belt will be replaced by your mechanics:

1. Disconnect the vehicle battery to prevent short circuits and sparking.

2. Remove the serpentine belt. The serpentine belt tensioner needs to be loosened first.

3. Remove any components or engine accessories that block access to the timing belt cover. This may include the radiator fan, alternator, power steering pump or AC compressor. The cooling system may also need drained.

4. Remove the crankshaft pulley and the timing belt cover.

5. Rotate the engine to top dead center or whichever rotation is specified in the vehicle service manual. Usually a special tool is used to lock the camshaft sprocket(s) in place to prevent rotation. With the camshaft locked, you can now remove the timing belt.

6. Typically, the timing belt tensioner is removed and replaced, as well as the water pump if it is nearby.

7. Referring once again to the vehicle service manual, the new timing belt can be fitted. Ensure the belt is aligned with the correct timing marks (if any).

8. Following the vehicle service manual, the engine can be rotated by hand to verify camshaft timing is still correct.

9. Once the belt installation is verified as correct, reassemble all of the removed components.

10. Replace or top off any fluids that were drained.

This is a very simplified overview of the timing belt replacement process. The key to this repair is keeping the camshaft sprocket(s) timed exactly with the crankshaft. It is tricky to line up the camshaft sprockets perfectly on a complicated dual overhead cam V6 or V8 engine, which adds to repair time.

Do it yourself or leave it to the experts?

It is best to have your timing belt replaced by an expert mechanic. Many of our mechanics are ASE certified and are committed to getting the job done correctly.

Feel free to make an appointment for your timing belt replacement at Don's Pro Technology Auto Repair. The shop is located at 230 E. Tehachapi Blvd., in Tehachapi and can be reached at (661) 822-1600.