Today we want to talk about timing belts. They’re something that many people don’t know much about and yet your vehicle won’t run if it’s broken – and it could cause many thousands of dollars damage if it does break.

A broken timing belt is usually a tale of woe. Even though timing belt replacement is scheduled in the owner’s manual, it’s not the kind of thing that people remember because it’s not well understood.

Let’s review what a timing belt does. As you know, the engine’s power is generated in the cylinders. A piston rides up and down in the cylinder. During the first down stroke, an intake valve at the top of the cylinder opens and air and fuel is drawn into the cylinder. Then the piston returns to the top, compressing the fuel and air mix. At the top, the spark plug fires, igniting the fuel pushing the piston down in the power stroke.

As the piston once again returns up in the final stroke of the cycle, an exhaust valve opens at the top of the cylinder and the exhaust is pushed out. The timing belt is what coordinates the opening and closing of the intake and exhaust valves. It’s called a timing belt because the valves have to open and close at just the right time.

Now, not all vehicles have timing belts. Some have timing chains. Like the name implies, they use a chain rather than a belt to perform the function. It used to be that most engines used timing chains, which are extremely durable. Manufacturers started using belts rather than chains to save money in the manufacturing process.

So now were left with a component that can break. They sort of shifted the problem to us. There are two broad categories of engine design: interference and non-interference. If the timing belt on a non-interference engine breaks, the engine simply stops running. That could be very dangerous depending on where you are at the time, but it causes no internal engine damage.

Interference engines, on the other hand, will get real messed up when the timing belt breaks, because the valves will actually fall down into the path of the pistons. Things get chewed up when that happens and it’ll cost thousands to repair the engine.

So, what are the warning signs? Unfortunately, there really aren’t any. There aren’t tell-tale sounds. In some vehicles, a technician may be able to see part of the belt for a visual inspection, but many have a cover that’s in the way. The reality is that if the belt slips even one notch, it might as well be broken for all the damage it’ll cause. There’s no middle ground.

So how can we avoid these problems? Simply replace the timing belt when your owner’s manual calls for it. It can be 60,000 miles; it might be 90,000 or 100,000 miles.

The point is, if you have 60,000 or more miles, ask your service adviser right away if your manufacturer requires a timing belt replacement. Sometimes you can go quite a while without a failure, but we’ve seen them happen within a couple of oil changes of being due. It’s not worth the risk.

What does it cost to replace a timing belt? Well, that really depends on what kind of car you have. I can tell you that it’s usually not very easy to get to the timing belt – you often have to remove some accessories to get at it. It isn’t a cheap procedure, but it’s a fraction of what it could cost to repair the damage caused by a failure.

At AutoNetTV we’re all about trying to prevent costly repairs, keeping you and your passengers safe and increasing your driving enjoyment.

Your cooling system is very important.  It circulates coolant through the radiator and your engine to protect your car from overheating. There are five main components to the cooling system: the radiator, the radiator cap, the hoses, the thermostat and the water pump.

The water pump’s like the heart of your cooling system, circulating the fluid throughout.  It’s a small pump that’s driven by the engine: usually by belt, but sometimes by a chain or gear.

The water pump only operates when the engine’s running. Water pump failure is pretty routine.  Some start failing at around 40,000 miles, but most fail by 100,000 miles.  Consult your owners’ manual or service technician to see what’s recommended.

Since a water pump either works or it doesn’t, you need to change it when it fails. Water pumps fail in one of two ways: the bearings fail or they begin to leak.  It’s possible to have a leak from a cracked water pump, but it usually leaks at the gasket where it attaches to the engine.

So how can you tell when the water pump is failing? If you can hear a low-pitched grinding sound coming from the water pump – it’s got a problem.  If you can see coolant in that area, you’ve got a leak.

Some water pumps are driven off the timing belt.  They might be under a plastic cover so you can’t see the water pump.  Look for coolant on the driveway.  If you see some, have your service center check it out.

Most timing belts need to be changed at 60,000 miles – some longer.  It’s a good idea to change your water pump at the same time if it’s one of those that’s driven off the timing belt.  To start with, 90% of the work’s already done with the timing belt change. And, if you don’t, and develop a leak later, you’ll have to change the belt again along with the water pump because the belt will have been contaminated by the leaking coolant.

You can replace your water pump with a brand spankin’ new one or with a rebuilt pump.  Rebuilt will save you some money, but ask your technician what he thinks. Don’t feel too bad if your water pump gives out.  They will all wear out eventually.  Your service technician can get you back on the road and on with your life.

Ever heard the sad tale of a staggering repair bill from a broken timing belt?  Bad news.  Let’s take a lesson from their woes and remember to think about our timing belt.

First, let’s review what a timing belt does.  The top part of the engine, over the cylinders is called the cylinder head.  The head contains the valves.  There’s at least one valve that lets the fresh air into the cylinder.  This air, mixed with fuel, burns to create power.  Then another valve or two open to allow the exhaust out of the engine.  Each cylinder has 2 to 4 valves – that’s 12 to 24 valves for a V-6, up to 32 values on a V-8. The opening and closing of the valves is done by a camshaft. The timing belt uses the rotation of the engine to drive the camshaft which opens and close the valves. It’s called a timing belt because it has to be adjusted to rotate the camshaft to keep proper time with the engine so that everything’s in sync.
The timing belt is a toothed rubber belt . But some cars use a timing chain or timing gears instead of a belt. Timing chains and gears are much more durable, but manufacturers are using belts more because they are quieter – and cheaper.  If you have a small or mid-sized passenger car, crossover or mini-van, chances are you have a timing belt.

Unfortunately, timing belts fail without any warning.  That shuts you down right away.  A technician can inspect your timing belt and look for cracks and looseness.  But getting to the belt to take a look can be almost as much work as changing it on some cars. That’s why manufacturers recommend replacing the belt from time to time.  For most vehicles it’s from 60,000 to 90,000 miles or 95,000 to a 145,000 kilometers.  If your owners’ manual doesn’t specify an interval ask your service advisor.

One AutoNetTV producer has had two timing belts fail.  The first was while he was waiting at a stop light – that repair cost several thousand dollars.  The second was while driving on the highway – that one cost more than twice as much.  Both had the cars out in the shop for three weeks. His cars had what we call “interference engines”, meaning that the valves and pistons are very close to each other.  If the timing belt slips even one notch, the pistons will slam into the open valves.  That’s why our friend’s highway failure was so much more expensive – his engine was traveling so fast that the valves were smashed and they chewed up the cylinder head.

A non-interference engine will just shut down if the timing belt breaks.  You’re stranded, but the engine doesn’t suffer permanent damage. In both cases, our hapless friend was just a couple oil changes past the recommended interval for changing the timing belt.  This is one of those things that you just cannot put off.  Now replacing a timing belt is not cheap – but repairs for a broken belt can be many times as much.

Check your owners’ manual right away – especially if you have more than a 60,000 miles or 95,000 kilometers.  You may need to get that belt replaced right away.  And on many cars, the timing belt drives the water pump.  So, it may be a good idea to replace the water pump while you’re at it because 90% of the work required for the new pump is already done with the belt change.  Doing both at the same time saves you a lot of money because as they say, “timing’s everything”.