7 Tips for Changing Your Own Timing Belt
Many vehicles use a timing belt to adjust the position of the valves and crankshaft. This adjustment allows the engine to get the most out of each combustion process. If you have experience working as a mechanic in a factory, changing a timing belt can be a great next step to improve your DIY skills.
If you’re new to engine maintenance, there are a few things to keep in mind to ensure the job goes smoothly and only once.
Timing Belt Replacement Tips
1) Do Your Research
It’s a good idea to do as much research as possible before embarking on any major repair job. What are some common mistakes that other owners have encountered? What parts will be needed? Have any owners discovered any tricks that make the job much easier?
Do you have an interference or non-interference engine? With a non-interference engine, the risk is lower because it is impossible for valve-to-valve or piston-to-valve contact to occur, even if the engine timing is significantly different. Make sure the part number of the part you purchase matches your specific VIN. Many models come with several different engine options. Parts may be very similar, but are not always compatible between trim options.
Some engines require cylinder 1 to be at top dead center (TDC). Other engines require the piston to be mid-stroke (many Subaru engines operate like this). Many engines don’t even have a timing belt.
Be sure to find the correct configuration for your specific timing belt replacement. You’ll also need to know the correct order for installing the belt, adjusting the play, and installing the timing belt tensioner.
Each engine manufacturer uses slightly different implementations for these, so it’s a good idea to understand the nuances of your particular engine before you start working on it for the first time.
2) Buy a Factory Service Manual (car repair manual).
A Factory Service Manual (FSM) is a book that lists all the systems and specifications for a particular year, make, and model of vehicle. The target audience is primarily service technicians and general mechanics.
Factory service manuals contain everything from wiring diagrams to troubleshooting procedures for common problems. They also contain torque specifications for all the fasteners on your vehicle.
Haynes and Chilton repair manuals are great because they’re cheap and easy to read. However, nothing beats the OEM manual when it comes to the level of detail of how the various systems interact. You can also often find the best exploded views (also called exploded diagrams) for various systems in the factory service manual.
3) Get a torque wrench
A torque wrench allows you to measure the tightening force you apply to fasteners. When working on an engine, it is important to follow the manufacturer’s torque specifications for each fastener. Most modern engines are made from aluminum. The threads on aluminum components are much more easily damaged than the threads on iron or steel components. When assembling your engine, always consult the manufacturer’s service manual for all torque specifications. If the bolts are not tightened enough, engine vibrations can cause them to loosen after thousands of miles.
Overtightening the threads can stretch the threads (also known as “flow”), distort the component they fasten, and damage the threads. Most damaged threads can be repaired, but it takes a significant amount of work. Worn threads are typically repaired using a Heli-Coil or Time-Server kit.
4) Turn the motor by hand
After installing the new timing belt, turn the engine by hand a few times. Make sure the engine turns smoothly. If the motor seizes or runs sluggishly, check its operation.
When turning the engine, make sure you turn the engine in the direction you want the crankshaft to turn. Usually this is clockwise, but check your manufacturer’s service manual. Running the engine backwards is not good and can throw off the timing if you haven’t installed the timing belt tensioner yet.
5) Recheck your time settings
It’s no fun putting your engine back together only to have it idle badly because of bad timing. Check your timing marks again after cranking the engine by hand a few times. When you return to the original alignment configuration, the markers should be in the exact same place.
6) Maintenance in the meantime (water pump failure)
Most timing belts require a proper disassembly of the engine. After all that effort, there may be a few other components that are very easy to replace if they start to deteriorate.
Common examples of components that may need to be replaced during the job include the front main seal, camshaft seal, valve cover gasket, idler pulley, timing belt tensioner, thermostat, various cooling hoses, water pump, etc.
7) Have a spare vehicle on hand
If something goes wrong, it’s a good idea to arrange for a loaner vehicle while your vehicle is at the repair shop. A timing belt repair can be completed in as little as an hour by an experienced mechanic.
It will probably take at least a weekend if this is your first time doing this job. You may need to order additional parts, which could delay your schedule.
Bottom Line
If you can change your brakes, you can probably change your timing belt yourself. This is a great way to learn more about working on engines and cars in general.
When in doubt, search for information about your specific vehicle on YouTube or forums. Other vehicle owners who have done the work will probably have great tips to help you get started.
