The clutch is the lifeblood of your car. Without it, the engine has no way at all to distribute its power to the wheels, and without power going to the wheels, you’re just going to be sitting there making a lot of noise.
You can get similar momentum-lacking results when your clutch wears out. And when it does, you may be wondering why the garage has given you an eye-watering quote. Much like when we talked about head gasket failure, the reason is simple: changing your clutch is a big job.
Before we get to that though, let’s look at how a clutch works.
How a clutch works
Your clutch takes power from the engine and then delivers it to your gearbox, which in turn delivers it to your wheels. It’s a very stressful job, especially when you consider that even at idle, your engine and consequently the flywheel – the bit the clutch grabs on to – is spinning at 1,000rpm.
Yet even so, you lift your foot off the clutch pedal and as you do, the clutch plate will roll up its sleeves and grab the spinning flywheel. And it will do it at all speeds, as you merrily drive along.
The clutch is subject to a lot of wear and tear, and that can be exacerbated by your driving style. When your foot is off the clutch pedal, or when your foot is pressing it all the way down, that’s when the clutch is at its happiest. It’s either clamped between engine and gearbox or spinning freely respectively.
Hold the pedal half way though, and you’re effectively grinding it away. That’s what people mean when they say you’re riding the clutch. The same thing can happen when you operate the clutch too slowly.
We’re sure you don’t do that though. Instead, you’re more likely to suffer from general failure, which given that the clutch is a wear and tear part, is unavoidable. But what are the signs that your clutch is going?
When a clutch needs replacing
Wondering if a clutch can cause a burning smell? Drive a high-mileage car that's still on its original clutch up a long, steep hill in a high gear and chances are you'll notice a horrid, burning, earthy odour that could make a skunk blush after a while. If there is even a little bit of slip going on, you’ll smell it.
New clutches don’t tend to give off bad smells, but can still slip. Why does a clutch slip? It happens because the clutch plate is so worn that it simply can’t grab the flywheel anymore, so it just slips and fruitlessly tries to put power to the gearbox.
You’ll know if your clutch is slipping because it simply won’t drive, or it will, but very slowly and at about 5,000rpm.
Can a clutch be adjusted?
Modern cars tend to use a slave cylinder and a hydraulic clutch. These are self-adjusting as the clutch wears, so there's nothing that can be done when it starts to slip apart from change it.
Old models are fitted with a clutch lever and cable. This allows for adjustment at regular intervals. In fact it demands it to avoid slippage. So you can see why this tech has been replaced by the self-adjusting clutch.
Clutch and flywheel replacement cost
So what about the repair? Why does a new clutch cost so much? It's largely because of where the clutch is located, which is in the bellhousing - the space between your engine and gearbox. So to change the clutch, you have to separate the two, which is a fairly big job.
As such, it may mean the engine has to be lifted, or dropped lower depending on the car, to make enough space to crack the gearbox and engine apart. This takes lots of time.
If you drive a rear-wheel-drive car you’ll be pleased to hear that your mechanic has an easier job. It still takes a lot of time, but because the engine and gearbox run longitudinally, it’s just a case of jacking the car up, removing the propshaft, unbolting the gearbox, yanking out the old clutch, fitting a new one and then screwing it all back together. Simple. Still a good day’s labour, but simple.
If your car is front-wheel drive, the chances are (unless you drive an old Audi A4) the engine is transverse, meaning it runs the across the car rather than along it.
That means everything is crammed into a much smaller space, so it’s a lot harder to work on. It could be double the time of a clutch change in a rear-wheel-drive car.
So, if your clutch does go, don’t get annoyed thinking the garage is trying to pull the wool over your eyes. It’s a big, labour-intensive job.
Just be glad the garage will do it for you, and if you need convincing, just have a look under your bonnet and ponder on how you’d get at the clutch yourself!