What are timing belts and why do they cost so much?
Updated 6 Apr 2021
Somewhere around each 40,000 to 150,000 kilometres – it varies from model to model – servicing your car gets to be a big pain in the wallet. And often the extra expense is all down to a crucial part of the engine called the timing belt.
To avoid you coming to a halt in the middle of the road, because of a banging, crash of pistons and valves fighting with each other, let’s investigate what the timing belt is, what it does, and why it costs so much to replace or repair.
Have you just received a quote for a car service and wondered why you will have to pull out the plastic to pay for it? It’s probably an indication that the service you’re having done includes the replacement of your timing belt, or timing chain (different names, but they do the same job… more on that later).
A timing belt is one of the more expensive and intensive services your vehicle will go through, second only to the non-service task of replacing or reconditioning the engine. Which is what you might well be doing in the future if you don’t replace the timing belt when recommended!
If you avoid doing this service and the belt or chain stretches, deteriorates, or breaks, it will more than likely cost you an engine without any warning. So the cost of attending to the timing belt is well worth it in the long run.
What does the timing belt do?
Unless you have gears directly driving your camshaft, as part of an internal combustion engine you will have either a timing belt or timing chain performing that task. The belt or chain synchronises the crankshaft’s rotation with the engine valves, allowing them to open and close at the correct times during the air intake and exhaust stroke.
Timing belt or timing chain?
Before moving on, we should tell you that while the predominant part used is a timing belt, your car engine could instead use a timing chain.
A timing belt is usually a toothed belt, and a timing chain is a roller chain. A timing belt has in recent history been the more commonly used part, but car makers are using a timing chain more often these days, as they find them to be more durable than belts.
When to change a timing belt
Some old school mechanics may tell you to replace the timing belt every 100,000 km. While this may have been the case 20 years ago, nowadays you need to do your homework as every make, model and engine has different requirements.
In modern engines manufacturers recommend replacing the timing belt from between every 40,000 – 150,000 kilometres, depending on the engine. If you only use your car now and again and don’t do many kilometres, you will still need to have the belt/chain replaced based on the age of the vehicle. Timing belts/chains can deteriorate and/or stretch over time.
Why does it take so long to fix?
You won’t want to hang around and wait while they do this service. All vehicle types are different, but allow at least 3 to 8 hours for this service, all going well. To fix the timing belt the mechanic has to:
- strip the front of the engine
- check seals, pulleys, and water pump
- change the timing belt, plus kit if needed
- set the camshaft/valve timing
- and then test it all
In some cases the mechanic will also need to remove the front section of the vehicle, and on some front-wheel drive vehicles lower the engine to be able to access it, which is why it can take a long time.
Possible extra costs
Whilst the mechanic is pulling the front of your engine apart they will probably recommend you replace your water pump and coolant at the same. Given the age/mileage of the vehicle, the possibility of the water pump failing not long afterwards is higher, and with this usually being a highly labour-intensive job, doing both while you have the engine pulled down, replacing the belt and the pump it’s the smart thing to do. Pretty much the only additional cost you’re incurring is the price of the water pump, rather than paying for the labour twice.
The mechanic may also need to replace hydraulic tensions as part of a kit, instead of just the belt. It is best to lock in and fix a timing belt service prior to it getting done as this service has the ability to take longer than expected. So put your mind at ease by fixing the price before they commence.
Most mechanics can get the job done without any concerns, but there are some questions you may like answered before you select the mechanic:
- Does the mechanic have the required tools to get the job done?
- Is the mechanic experienced?
- Have they replaced the timing belt on your type of vehicle before?
- Will they allocate enough time to do this service, or will they be rushed to get it done?
It’s a must-do to plan ahead, to budget for a high-price service, and, importantly, allow the mechanic the time required to do a great job. Expect to be without your car for at least a day during this type of service.
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Rachel spent her early adult life around cars, motorsport and hands-on with her own cars. This interest moved into various careers within the Automotive industry. Joined with her passion for writing, Rachel loves putting the two together to share her experience, so we can all become AutoGuru’s.