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Broken Timing Belt or Chain Repair
Typical Cost: Low - High
Mobile Repair? Yes
Typical Lead Time: 1-2 days
What does a timing belt or chain do?
The timing belt/chain has a specific number of teeth/links that are matched in perfect harmony with the cog on the crankshaft and the cogs on the camshaft(s). This is set to rotate the camshaft so the valves open at the precise time they are meant to in correlation with the rise and fall of the engine's pistons.
What happens if a timing belt or chain breaks?
As the pistons and valves need to operate in perfect synchronization with each other, when a break occurs in the belt/chain, this will not happen. The result is that the piston will collide with the valves with considerable force, bending them and potentially damaging the pistons themselves, the cylinder head, camshaft and cylinder bore.
In other words, it ends in one big mess inside the engine! It doesn’t matter what speed the car is at, it could even be stationary, it is the revolution speed of the engine (RPM) that causes the damage.
Please note
You cannot see the timing belt or chain on an engine, it is hidden behind covers. If you can see a broken belt it will be the auxiliary drive belt, this is NOT the timing belt and very easily replaced. Please view https://www.clickmechanic.com/help/articles/357/auxiliary-drive-belt-replacement for more information on drive belt replacement.
How do I know if the timing belt or chain has broken?
The initial clue is that the engine will cut out pretty quickly. As the damage occurs so fast, you don’t even hear the collision over the engine noise, it is that instant.
The engine will not then re-start of course, although it may still turn over if you try.
You could potentially take off the oil filler cap on some engines and see if the camshafts are turning while someone tries to start it, however this is not always possible to see. Therefore a mechanic would be needed to check both physically and diagnostically (camshaft and crankshaft position sensors will not be in synchronization).
So what needs to be done?
Firstly, the vehicle will need recovering back home!
A mechanic will then be needed to strip the cylinder head off the vehicle so they can assess what damage has occured so a quote can be put together to repair it. Obviously a new timing chain or belt will be needed (and a water pump if it is on the timing belt circuit), new valves, new rocker arms, head gasket and engine oil and coolant. That is the bare minimum you are likely to get away with.
The quote will take into consideration the time already taken to this point.
Therefore, the mechanic will price this work up for you and you can decide whether you wish to proceed or not.
Important
If you choose not to go ahead with the quotation or need to wait until finances are available for the repair, the mechanic will NOT put the engine back together. There is no point in doing so as it will either need to be repaired, replaced or the vehicle scrapped. So we wont charge you for a pointless number of hours to do it, but the parts will be left in a tidy condition in a location of your choice.
Next steps (to book in from your quote)
All you need to do is click on the quote link in the email we sent you and then click on the green Next step button
For more information on how to book in, please view https://www.clickmechanic.com/help/articles/401/how-to-place-your-booking-with-clickmechanic
Next steps (new enquiry)
If you haven’t done so already, please complete our enquiry form for a custom quote
https://www.clickmechanic.com/mir-requests/quote-missing