What Happens When a Timing Chain Breaks While Driving

Last Updated on December 2, 2020

The timing chain is a critical component of the internal combustion engine. Its function is to keep the camshaft and crankshaft rotating together at the same speed. This enables the valves of the engine to open and close at precisely the right times.

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These are the valves responsible for allowing air and fuel to flow into the internal combustion chamber. As you probably know, the engine needs the proper amount of air and fuel mixture for the ignition to be successful. That way, the proper amount of power can be generated to satisfy the demands of the vehicle.

If the timing chain were to break, it will jeopardize the entire internal combustion process. This means you won’t be able to drive your vehicle anymore.

Related: Timing Chain vs Timing Belt Differences

What to Expect

timing chain

If you want to know what exactly will happen when the timing chain breaks while driving, it depends on whether you have an interference engine or a non-interference engine. Although they are both internal combustion engines, the “interference” word refers to the timing configuration of the engine.

No matter which type of engine you have, a broken timing chain will cause your engine to immediately stop running and turn off. If you’re driving, you’ll have to pull over quickly to the side of the road before you lose all your momentum.

When you have an interference engine, the stroke of the piston and valve consume the same area of the cylinder. The timing chain is what prevents them from coming together. However, if the timing chain breaks, the piston and valve will collide. The result will be a damaged cylinder head, valve, piston, cylinder, and/or camshaft.

These are very expensive items to repair or replace. You’d probably be better off either purchasing a new engine or trading in your car for a new one.

See Also:  Symptoms of a Faulty Timing Belt

If you have a non-interference engine, the result of a broken timing chain will not be as severe. It will simply cause your engine to turn off but that’s all. The valves, pistons, and other vital components of the engine will not be damaged.

But still, you don’t want to take the chance of being stranded somewhere because of this. That is why it is better to regularly maintain your timing chain and make sure it is doing okay.

If it looks or sounds like it is getting too worn out, then simply bite the bullet and replace the timing chain with a new one. It is a lot cheaper to do that than having to deal with severe engine damage.


13 thoughts on “What Happens When a Timing Chain Breaks While Driving”

  1. This information has been very helpful. The details are so understanable, I feel like I could repair my own vehicle.Well at least I can explain to the repair shop what’s happening to my car. Keep up the good work!!

    • If your engine is a non interference engine, all you likely have to do is replace the timing belt.

      If your engine is an interference engine, there is a chance that you had valve on valve contact, or valve to piston contact. This could cause some pretty expensive damage, unless you got really lucky and the timing belt broke in a position where there was no contact. In this case, you can try replacing the timing belt and see what happens. If your engine doesn’t fire after the timing belt replacement, a leak down test may help you determine what went wrong, as it will show you where air is rushing through when the combustion chamber should be sealed (on the compression stroke).

  2. My timing chain went on my 2014 beetle while the mechanics were working on it they found that my camshaft had too much give and should also be replaced. Total estimate is $3400 give or take. Car was purchased CPO and I still have 14 payments left. Should I repair car or roll the remaining balance into something new with a warranty? Concerned that I put this $ into repairing the top half of the motor and then end up getting hit with a $2000 bill to repair the bottom half six months down the road. Is this a rational concern or should I feel ok that the top is the issue and I’m good to go from here?

    • That is completely up to you. Without having seen the car, knowing much about your situation, or knowing the mechanic’s assessment, it’s very difficult for me to give advice on this situation.

      Sometimes it’s better to stick with the problems you know, rather than rolling the dice on a different used vehicle.

      On the other hand, your mechanic needs to be really honest with you about the current state of the vehicle. If he or she foresees many problems in the near future, it may be best to cut your losses and find a different vehicle in better condition.

  3. Had the top timing chain on bmw 118 go when at a red light …. but it’s the dreaded N47 engine any idea if replaced the car would run again?

    • That one is an interference engine, right? If so, there is a very strong possibility that other components were damaged when the timing chain let go.

      The car could probably run again, but it depends on how much effort (and money) you want to put into it, and the extent of the damage.

  4. It looks like the timing chain on my 2013 Kia Sorento broke. The car just stopped and wouldn’t start. Slight smell like something burned. Battery & oil all good. Took to a local mechanic and he inspected it (not a deep dive) but said it looks like the timing chain. Said he saw what looks like small metal pieces in the oil. I believe the 2013 Kia Sorento SX V6 is a interference engine. I’m wondering if it’s worth taking it to another mechanic to do a deep dive to confirm it’s the timing chain?

    • It’s up to you if you want to take it to another mechanic for a second opinion. If your timing chain broke and it’s an interference engine, you’re looking at an expensive repair. Cars are misdiagnosed all the time by not looking closely enough at the problem. A deeper dive will cost more but it’s worth it to know exactly what the problem is.


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