Los Altos Auto Repair

Hello Los Altos auto owners, let's talk about your often-unnoticed but extremely important PCV valve. The energy from exploding fuel is what powers your engine. But some of the vapors from the explosions escape into the lower part of the engine, called the crankcase. The crankcase is where your engine oil hangs out. These gases are about 70% unburned fuel. If the gases were allowed to stay in the crankcase, they would quickly contaminate the oil and turn it to sludge. Los Altos folks know that sludge is one of the biggest enemies of your engine, clogging it up, eventually leading to expensive failures. Also, the pressure build up would cause seals and gaskets to blow out. Therefore, these gases need to be vented out.

Pre-1963, gasoline engines had a hose that let the poisonous fumes vent out into the air. In 1963, the federal government required gas engines to have a special one-way valve installed to help reduce dangerous emissions. (Can you imagine how polluted our Los Altos air would be if every car had been releasing those poisonous fumes for the last fifty years?) Diesel engines are not required to have these valves.

The positive crankcase ventilation, or PCV, valve routes crankcase gases through a hose and back into the air intake system where they are re-burned in the engine. Fresh, clean air is brought into the crankcase through a breather tube. It's really a pretty simple system, but it does the job. The re-circulating air removes moisture and combustion waste from the crankcase, preventing sludge. This extends not only the life of your oil, but the engine as well. The PCV relieves pressure in the crankcase, preventing oil leaks.

Eventually, the PCV valve can get gummed up. Then it can't move enough air through the engine to keep it working properly. If the PCV valve is sticking enough, you could have oil leaks, excess oil consumption and a fouled intake system. If you experience hesitation or surging or an oil leak, it may be a sign of PCV valve problems. Your owners' manual may give a recommendation for when the PCV valve should be replaced - usually between 20,000 mi/32,000 km and 50,000 mi/80,000 km. Unfortunately, some manufacturers don't list a recommendation in the manual, so it can be easy to overlook.

Many PCV system problems can be diagnosed with an automotive analysis by your personal Allied Auto Works service professional. Fortunately, PCV valve replacement is both quick and inexpensive at Allied Auto Works. Proper oil changes will greatly extend the life of the PCV valve. Skipping a few recommended oil changes can allow varnish and gum to build up in the valve, reducing its efficiency. So now when your Los Altos service technician tells you its time to replace your PCV valve, you will know what he's talking about. If you have had your car for a while and this is the first you've ever heard of a PCV value, ask your service professional to check yours out or call Allied Auto Works at 650.968.7227.

Today we want to talk to Los Altos drivers about timing belts. They're something that many drivers 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 most Los Altos area auto owners remember because it's not well understood.

Let's review what a timing belt does. As most 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. The leading vehicle manufactures started using belts rather than chains to save money in the manufacturing process. So now Los Altos drivers and their advisors at Allied Auto Works are 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 for drivers depending on where they are at the time, but it causes no internal engine damage.

Interference vehicle 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 a chunk of change to repair the vehicle engine.

So, what are the warning signs? Unfortunately, there really aren't any. There aren't tell-tale sounds. In some vehicles, a technician from Allied Auto Works 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/97,000 km; it might be 90,000 or 100,000 miles/145,000 or 160,000 km. The point is, if you have 60,000 or more miles (97,000 or more km), ask your Allied Auto Works service advisor right away if your vehicle requires a timing belt replacement.

Contact Allied Auto Works to learn more about your car's timing belt
You can find us at:

2073 Grant Road
Los Altos, CA 94024
650.968.7227
http://alliedautoworks.com

Sometimes Los Altos drivers 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 in Los Altos? 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 Allied Auto Works in Los Altos, we're all about trying to prevent repairs, keeping you and your passengers safe and increasing your driving enjoyment.