Skip the auto shop - Our mechanics make house calls

Q: Timing belt needs replacing

asked by on

My car won't start. I think it might be the timing belt.

If your car is not starting, and you suspect the timing belt, the first thing we could do is have the belt inspected. Remember, when the timing belt breaks only half of your engine is turning. This is why you hear a very characteristic sound while the motor is spinning and you don’t hear the "puffs" or coughs you normally hear when a cylinder makes compression. Also, it will spin much faster if there is a brake in the belt. The bad news is that a lot of engines are built in a manner that do not permit this. When a belt breaks the bottom half of the engine continues to spin but the camshafts stop moving. That means the valves stop moving.

Let’s say this happened when both intake valves for cylinder 1 were open. Now, if the engine were an "interference engine," when the piston got to the top it would slam into the open valves because it was not built with enough clearance for valves to be open when piston was at top. In an engine like this, when the belt brakes and serious engine damage occurs, this will usually require an entire engine replacement. So checking to see if your car has an interference engine would be the second thing on our list. An inspection of a mechanic will let you know if your timing belt needs replacement. Sometimes it will be okay to only replace the timing belt, however the best way to do this job would be to replace the idlers, tensioners, and water pump, along with the timing belt to ensure that all new components work well together.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Timing chain too loose

Hello. The rattling sound that you are hearing could be coming from several different areas of the engine. Your drive belt pulley could be bad, a compressor clutch could be loose, or the alternator pulley or timing chain could be...

Q: We have changed the fuel pump, air filter, battery, spark plugs on my nissan xtrail and the car still wont start

Hi. I'm thinking you have a broken timing belt causing the SUV not to start. If the timing belt breaks the engine jumps time and the engine has to be in time for it run. If the timing belt is...

Q: Shaking and stalling during low idling

There are no common issues that would cause this problem - especially with the relatively low mileage. I recommend testing the computer for codes causing the stalling you have. If the computer sees the stall, it should set a code...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...