wh-AskMechanic-Nov12

Dear Ask a Mechanic,

My 2009 Toyota Corolla has a warning light that stays on. I’ve brought it into the dealership, and they say it has to do with the tire pressure. At the time, they did something to clear the warning light and checked the tires. They said it would cost a lot of money to replace the sensor that is causing the warning light. They said that if I didn’t want to pay for it to be replaced, I could just live with the warning light being on and just be sure to check the tires now and again. But it’s annoying seeing the light on every time I’m driving. What do you think? – Tire tired

Automotive tire pressure monitoring systems, generally referred to as TPMS, have been around for more than 30 years. The earliest design, co-developed by Bosch and Porsche, used specialized wheels with calibrated pressure switches built into them. The system was costly and not widely used.

Improvements in technology eventually allowed sensors powered by internal batteries to do the job. Each sensor transmits its information to the car’s computer using radio signals. While these sensors have become smaller and capable of transmitting more information (such as tire temperature and sensor battery strength), the basic premise of what is known as direct TPMS remains the same today.

At the same time, anti-lock brakes (ABS) have also become more common and its controllers are now much more sophisticated. This is also a way that tire pressure can be detected. Known as indirect TPMS, this method uses the ABS wheel speed sensors to monitor average tire speeds relative to one another.

Low pressure will result in a tire’s overall diameter becoming smaller. The tires sidewalls get smooshed out and the wheel is closer to the road, meaning the tire’s overall height is less and it will rotate slightly faster than a properly inflated tire. Eventually the average tire speeds reveal the imbalance, and the ABS module will turn on the TPMS warning light.

Automakers frequently use either type. Your Corolla uses the direct kind with four sensors in the valve stems. Since they have batteries built in them, they have a finite lifespan. The battery is attached to the sensor, so replacing the sensor is required to replace the battery, and the tires must come off the wheels to do it.

Like you, I hate having warning lights on, and TPMS is a useful system when it works, so I’d want to fix it. Just know that the sensors are probably all the same age, so even if only one is dead, the others may not be far behind.

While factory sensors can be expensive, aftermarket sensors are widely available, functionally interchangeable and potentially far less costly. I would expect that it will cost well under $100 for each sensor to be replaced and installed. You’ll most likely have to go an independent shop for this option, though.

Ask a Mechanic is written by Brian Early, a Red Seal-certified automotive technician. You can send your questions to wheels@thestar.ca. These answers are for informational purposes only. Please consult a certified mechanic before having any work done to your vehicle.

Dealing with the pressure from a tire warning light

wh-AskMechanic-Nov5

Dear Ask a Mechanic,

I have a three-year-old Mini Cooper. Recently two tires developed a bump on their side walls. I do hit the occasional pothole, but never at any high speeds. Because the wheels on the Mini do not have a conventional inner tube, I was told I would have to replace both tires (they have less than 18,000 kilometres on them). There is no warranty or insurance coverage, and it has cost me $750. What is going on here? – Tire Dinged 

Unfortunately, you’re the victim of a couple of automotive industry trends. One is the market’s preference for larger diameter wheels and correspondingly shorter sidewalls. With less sidewall height to flex and compress, the likelihood that the tire will get pinched by something, like the edge of a pothole or a driveway lip, becomes even greater.

Mini’s use of tire sizes on the Cooper that are a smaller in overall diameter than what is common in Canada and the U.S. results in even shorter sidewalls.

Your cost sounds quite high, but you probably tried to match the remaining tires, which would be a major factor. Even if you didn’t, the Cooper’s less popular tires sizes mean there are fewer alternatives on the market. One of the Mini’s tire sizes, the 205/45R17, is a common factory fitment on Mazda’s MX-5, but the Japanese roadster doesn’t use run-flat tire

Run-flat tires are another factor in your replacement costs. BMW, Mini’s parent company, began transitioning to primarily using run-flat tires in the early 2000s, eliminating spare tires and saving on vehicle weight, space and production costs. The German automaker isn’t alone in using run-flat tires, Chevrolet’s Corvette has used them for three generations, but BMW is among the higher users of them in the auto industry.

The key benefit of these extended mobility tires is the ability for the heavily reinforced sidewall to safely permit continued driving without air pressure (albeit at reduced speed) far enough to reach a service station or garage. Most tire manufacturers have a policy of replacing and not repairing the tire once that happens. Some do not permit repairs at all.

Due to their heavier and specialized construction, run-flat tires are typically anywhere from 10 to 30 per cent more expensive than comparable tires. They also tend to increase ride harshness, a side-effect of the super-stiff sidewalls necessary for low pressure support. Many owners opt to replace run-flats with other tires (and rely on roadside assistance in a flat tire situation) when they buy a vehicle with them.

While it won’t help you with your car’s original tires, pro-rated Road Hazard warranties are available from select tire retailers and brands (often at additional cost) for future tire purchases, offering you a limited form of insurance protection.

Ask a Mechanic is written by Brian Early, a Red Seal-certified automotive technician. You can send your questions to wheels@thestar.ca. These answers are for informational purposes only. Please consult a certified mechanic before having any work done to your vehicle.

Ask a Mechanic: The reality of having run-flat tires

wh-AskMechanic-Oct29

Dear Ask a Mechanic,

I have a 2004 Mazda 6 with very low mileage, about 60,000 kilometres, and in pretty good working order. The only issue is when I drive in reverse and step on the brake. There is a peculiar squeal (it sounds like a wounded animal). My mechanic assures me there is nothing wrong with the brakes. Any suggestions on what could be causing the noise. – Squealing Brakes

Brake noises are the nemesis of many mechanics. There are plenty of obvious causes for squeaks, squeals or grinds, but if you inspect the brakes and nothing is seized, rusty or worn out, the source of these unwanted sounds can be tough to pin down.

The cause could just be due to what material the brake pads, and to a lesser extent the rotor, are made from. Inexpensive brake parts (and those meant for performance use) are prone to squealing when they are used.

The shims and retainers, as well as the dust and heat shields that are often behind the brakes, can all cause noise. Parts of the rotors and drums, areas not swept clean by friction like other parts of the brakes, can swell with rust and touch up against each other. This may only occur when they get hot, or when your vehicle is making a turn, as the wheel bearings will ever-so-slightly deflect.

Glazed rotors (or brake drums) can also result from excessively hard use and from infrequent or gentle use. In the latter, the wear surface lightly corrodes from ambient moisture while sitting, and then is polished off by the friction, becoming very hard and very smooth. Squealing, shuddering and loss of “bite” (resulting in greater braking effort being needed) can all result.

Because your Mazda is an older vehicle with very low mileage, there are additional possibilities. As vehicles age, rubber bushings in the suspension either harden, or – in vehicles that have been heavily undercoated or have appreciable oil leaks – soften and deteriorate. This can amplify sounds and vibrations. In some cases, the material hardens with time or even corrodes from the backing material. I’ve also seen pad material become saturated with undercoating overspray.

With only slightly less mileage than your Mazda 6 at 50,000 kilometres, the rear brakes in my mother’s 2009 Hyundai Sonata have recently developed a loud and annoying “moo” and accompanying vibration just as it comes to a stop. Her brakes aren’t even half worn yet and work fine otherwise. But I will still replace the pads and rotors with new ones when I do her seasonal tire change this fall, solely to banish the nuisance noise.

I suspect it’s a similar situation with your brakes. Your mechanic is likely telling you the truth that your brakes are fine. The solution is probably just new pads and rotors.

Ask a Mechanic is written by Brian Early, a Red Seal-certified automotive technician. You can send your questions to wheels@thestar.ca. These answers are for informational purposes only. Please consult a certified mechanic before having any work done to your vehicle.

Putting the stop to a squealing brake

wh-AskMechanic-Oct22

Dear Ask a Mechanic,

I own a 2006 Mazda MX-5 Miata that I store in my unheated garage during the winter. I put in a gas stabilizer and use a trickle charger on the battery. Not wanting to leave it for six months, about once every two weeks, usually on a nice day when it is around zero degrees Celsius, I warm up the car and then drive it around the block a few times until it gets to running temperature. I then put it away in the garage again. A friend suggested that, although this is great for the tires, it is not good for the engine. Would it be better to put it up on blocks for the whole six months? - Storage minded

The use of stabilizer in your fuel and a trickle charger to maintain your battery is spot on. When it comes to the trickle charger, just be sure that it’s a maintenance float charger and not a steady “on” low-amp type, as those can overcharge and damage the battery.

Your question is a tough one, as I partly agree with both of you.

A car sitting in one position for six months will flat-spot the tires. The permanence of those flat spots depends on multiple factors, including the temperature during the return to use, and the tires’ compound and construction. Michelin, for one, recommends lifting and supporting the car to take the weight off the tires when it is being storing for a month or more.

Personally, I’m not prepared to do that with my Mazda RX-8 as I need to be able to move it to access things in my garage when I am storing it. Instead, during storage I will add an extra eight psi (pounds of pressure per square inch) to my tire’s specified 32 psi to reduce the flat spotting and compensate for pressure loss from the cold. After hibernation, the resulting flat spots have always worked themselves out after driving around 10 kilometres.

While taking your ride out during the winter to do a couple laps around the neighbourhood can be good for the soul, I am still hesitant about recommending it, especially if your Miata only has summer tires on it. Several makers warn against moving a vehicle fitted with their performance summer tires at temperatures of minus-seven degrees or colder, as it risks permanently damaging them.

Even on a nice, warmer day, there is still salt dust and residue on the roads, so you’re also exposing your car to that. As well there is the moisture in the oil and exhaust systems, which – as your friend noted – a few laps around the block may not be sufficient to burn off.

Insurance is another consideration. It could be a hassle if an incident occurred at near-zero temperatures on summer tires. Sadly, your best bet is to leave your car parked, on stands, if possible.

Ask a Mechanic is written by Brian Early, a Red Seal-certified automotive technician. You can send your questions to wheels@thestar.ca. These answers are for informational purposes only. Please consult a certified mechanic before having any work done to your vehicle.

Be careful taking your summer ride on a winter spin

wh-AskMechanic-Oct15

Dear Ask a Mechanic,

I have a 2015 Honda Civic that I purchased new which only has around 27,000 kilometres on it. The vehicle’s maintenance reminders don’t indicate when the coolant should be changed, and whether it should be done based on mileage or not. It has been on the road for seven years now. What factors should be used to help decide when the coolant should be changed? – Coolant Curious

Time is a factor in the longevity of certain vehicle fluids. While transmission, differential and transfer case fluids tend not to break down or become contaminated by moisture very quickly, brake fluid and engine coolant both deteriorate with age.

The chemical properties of brake fluid make it hygroscopic, meaning it attracts and holds moisture, even from in the air. As such, Honda recommends that the brake fluid in your Civic be replaced every three years, regardless of mileage. This advice is typical industry wide, though it’s an often-neglected maintenance item.

Engine coolant (or antifreeze) has its own set of properties, not only those for resisting freezing and boil-over, but also for preventing the various metals in the engine, radiator and heater core from corroding. The additives in the coolant that help protect those parts are used up over time, which is the primary reason why it is recommended you change your car’s coolant regularly. The coolant’s actual freeze resistance is not reduced over time.

Because all of Honda’s modern engines use aluminum in both the cylinder heads and block, the antifreeze doesn’t get discoloured to the same extent as in applications where iron components are present, so the fluid may appear okay even when it needs to be changed.

Honda’s reliance on its Maintenance Minder system makes finding a specific time interval for replacing the antifreeze in your Civic a challenge, however we can deduce when to do it by looking at the automaker’s other vehicles.

For example, when I road tested a Honda Ridgeline back in 2017, I spotted a notice included on the emissions sticker under the hood that stated, “The factory installed long-life coolant must be replaced according to maintenance minder sub code 5, or at 10 years, whichever comes first. Thereafter every five years.”

As the Ridgeline uses the same Long-life Type 2 coolant as your vehicle and has a similar all-aluminum engine composition (albeit a V6, rather than a four cylinder), it’s a reasonable assumption that your Civic would have a comparable maintenance interval.

Critically, these lengthy intervals rely on using Honda’s Long-life Type 2 coolant or an equivalent product. Other coolant types will reduce the protection level and could possibly cause damage.

Ask a Mechanic is written by Brian Early, a Red Seal-certified automotive technician. You can send your questions to wheels@thestar.ca. These answers are for informational purposes only. Please consult a certified mechanic before having any work done to your vehicle.

Knowing when to change your vehicle’s coolant

wh-AskMechanic-Oct8

Dear Ask a Mechanic,

We have a 2016 Hyundai Santa Fe that we bought new. It now has more than 100,000 kilometres on it. I am slightly concerned because I can’t find information anywhere on when the timing belt should be replaced. We had to change it in our previous car, a Honda, when it reached the same mileage. When should it be changed in the Hyundai? – Maintenance Minded

It’s good that you have preventative maintenance in mind, particularly involving your vehicle’s engine and its timing system. Certain mechanical operations within the engine must be precisely coordinated, not just to run well and produce good power, but to keep valves and pistons from inadvertently trying to share the same limited space inside the cylinder.

Normally in an engine, the valves are closed whenever the piston is at the top of its stroke. A failed or jumped cam drive system can result in a collision between these parts causing damage, which can be catastrophic and expensive.

There are three main methods used to synchronize the valvetrain and crankshaft in modern engines: a toothed belt drive, a chain or – in a few rare cases – gears. Of these, only belts tend to have regular, defined service intervals.

In older vehicles that use a timing belt (or sometimes multiple belts), maintenance schedules often call for the belt to be changed at 96,000 kilometres. As the material used to make the belts have improved, and the technology around them has also developed, that has now changed to 160,000. (Please note that in some cases manufacturers may specify shorter service intervals under certain operating conditions, like the Canadian climate.)

You’ll be happy to learn that unlike your Honda, the engine in Hyundai’s 2016 Santa Fe’s uses a timing chain. Chains (and drive gears) are generally considered to be good for the life of the engine and replaced only when excessive wear or other factors warrant it. So, there’s no need for you to worry about it being overdue for maintenance.

While chains can occasionally fail, it’s more likely there’ll be indications – such as noise or a check engine light – if it does happen. It would be rare for an outright and spontaneous failure to take place if the vehicle is being driven with normal use. Most vehicles will never need timing chain maintenance.

Ask a Mechanic is written by Brian Early, a Red Seal-certified automotive technician. You can send your questions to wheels@thestar.ca. These answers are for informational purposes only. Please consult a certified mechanic before having any work done to your vehicle.

Timing when to change your timing belt

dreamstime_m_41870070

Dear Ask a Mechanic,

Three years ago, I bought winter tires and put them on the cast aluminum wheels of the Nissan Murano SUV I was leasing. I had a three-year lease and planned to trade the vehicle at the end of it. However, I have now bought out the lease and plan to keep the Murano for two or three more years. The winter tires have had little use. What should I do this winter, keep the cast aluminum wheels or change to steel rims. – Winter wonderer

Bravo for being among the enlightened folks that go to the trouble and expense of buying winter tires for a leased vehicle. Unfortunately, I can’t give you a solid answer on whether you should purchase a set of steel-rim wheels because there are important variables that come into play.

The first is that you don’t mention what size your factory wheels (and thus the winter tires) are. You did note, however, that you’ve bought out your three-year lease, so I’m going to assume that it’s either a 2019 or 2020 model, giving us only two possibilities: 18-inch (which come with the S and SV trim) or 20-inch wheels (which come with the SL and Platinum models).

If your Murano came with 18-inch wheels, it is possible to buy steel wheels that have the correct bolt pattern and centre bore (the size of the hole in the centre). On the other hand, if your factory wheels are 20 inches, you’re out of luck for buying steel wheels. I did some digging, and it does not appear you can buy 20-inch steel wheels with a compatible bolt pattern for the Murano.

That doesn’t mean you’re out of luck. You could buy alloy wheels in the appropriate size and fit instead. Aftermarket aluminum wheels have become far more affordable than they were historically. Finding a used set of factory wheels – which are not only guaranteed to fit properly and use the original nuts but will probably be of superior quality – is another alternative.

Having your winter tires mounted on a dedicated set of wheels has several benefits. Among these is reduced wear and tear and a lower risk of damaging the tires when they are being mounted or dismounted. You also will not be exposing your factory alloy wheels to salt corrosion, and, in the long-term, it will cost you less money.

The labour involved to remove and reinstall tires on a set of wheels and then rebalance them is substantially higher than simply exchanging mounted sets – often triple or quadruple the amount. Even with the added cost of needing four additional tire pressure sensors, after few seasonal swaps, the wheels will typically pay for themselves.

It will be up to you to decide whether buying a set of wheels will benefit you financially for the remaining two or three years you plan to keep the Murano.

Ask a Mechanic is written by Brian Early, a Red Seal-certified automotive technician. You can send your questions to wheels@thestar.ca. These answers are for informational purposes only. Please consult a certified mechanic before having any work done to your vehicle.

Ask a mechanic: A wheel of a winter tire question

wh-AskMechanic-Sept24

Dear Ask a Mechanic,

I consider myself to be handy, so when the power window switch in my 2013 GMC Sierra broke, I was confident that I could replace it. I bought a new one online, and it was easy to install, but now the only window I can control from that switch is the driver’s window. In fact, nothing else works from that door anymore. Even the heated seats, which aren’t part of that switch, don’t work. 

When I reinstalled the old switch, everything worked except the driver’s window (and only because that part of the switch is broken). I’ve double-checked that the switch I bought is correct. Why is this happening? – Pickup Puzzled

The simple answer is that the truck doesn’t recognize the new switch, but to understand why requires a bit of background.

Consider the way that power windows were traditionally wired. Look inside the driver’s side door and you would find power and ground wires for that window switch. You would also find wires running from the switch to the vehicle’s three other door windows. That is eight wires.

Now add wires for the speakers, power locks and mirror directions. You get the idea. Pretty soon the door harness looks like a trans-Atlantic phone cable. All those wires add to the weight, complexity and cost of a vehicle – and take up a lot of space.

The solution is that many modern vehicles use door modules and communication networks instead. The driver’s side switch is a micro-computer, sending and responding to signals over a data network to the modules in the other doors or parts of the vehicle. This means fewer wires and allows for some neat functions, like windows that can be rolled down using your key fob.

In higher-trim versions of GMC trucks like yours, the power locks, heated seats and mirror controls all pass through that switch. The automaker has made those switches VIN and configuration specific, which means that to work properly they must be programmed so the vehicle recognizes them.

Unfortunately for handy people like yourself, this means General Motor’s Service Programming System needs to be used, so it can only be done by a dealership or an independent shop. This also means a previously installed and used switch also probably won’t work, since it could confuse other modules in the Sierra when it shares its incorrect ID and data over the vehicle’s network.

Whether this is a clever theft-deterrent or a money-grab depends on your perspective.

Ask a Mechanic is written by Brian Early, a Red Seal-certified automotive technician. You can send your questions to wheels@thestar.ca. These answers are for informational purposes only. Please consult a certified mechanic before having any work done to your vehicle.

Changing a switch not as simple as it seems any more

wh-AskMechanic-Sept17

Dear Ask a Mechanic,

I have a 2017 Mercedes E300 4matic. When I brought it to be serviced last year, I was told the OK button on the left side of the steering wheel was broken, so the service reminder could not be reset.  I was told that to fix it, I would have to replace the whole steering wheel. I can, however, change the message by pressing the home button. My question is if it is true that the whole steering wheel needs to be changed or can just the button be replaced? – Busted Benz

There are all kinds of maintenance reminder systems out there. There is the simplest, user-defined mileage and time counter found in many Hyundai models and the more complex oil-life monitors, which also consider operating conditions, that are common in many domestic vehicles. Others, such as those in Hondas and BMWs, track and call-out multiple maintenance items.

Mercedes has had several comprehensive service reminder and tracking systems in its vehicles for quite some time now. One thing that has been common to all the ones I’ve encountered is that they’re able to be reset through some combination of pressing instrument cluster or steering wheel buttons. This is true of your E-Class, too.

Your unusual situation raises two questions. First is if you must replace the entire steering wheel to rectify the one faulty switch? And second, can the maintenance system be reset without fixing the broken switch? Thankfully, as you provided your vehicle’s VIN, I was able to make some specific inquiries.

Regarding the first question, no you do not have to replace the entire steering to replace the switch. The Mercedes parts dealer I use shows the switch is available as a separate item, costing under $300 (installation would be extra). I did not price an entire new steering wheel but replacing it would cost considerably more.

As to the second question, Mercedes-Benz Canada’s technical service team did confirm that the system in your E300 can be reset using Mercedes’ diagnostic tool. Obviously, few, if any, independent shops will own a Mercedes scan tool, so that pretty much means going to a dealership to have the vehicle serviced.

Could an aftermarket tool perform the reset? Perhaps. My Autel scan tool, for instance, often shows it as an option, but I am not sure whether it will work with your Mercedes model. Either way, you do have options that don’t involve getting a new steering wheel or having to live with the reminder messages always appearing.

Ask a Mechanic is written by Brian Early, a Red Seal-certified automotive technician. You can send your questions to wheels@thestar.ca. These answers are for informational purposes only. Please consult a certified mechanic before having any work done to your vehicle.

Ask a Mechanic: A new steering wheel not needed to replace a broken button

wh-AskMechanic-Sept10

Dear Ask a Mechanic,

I have a 2009 Chevy Cobalt that I use mostly for commuting from home to the local GO station. Right now, the heater fan only works on high speed, and it’s annoying. I’ve replaced the resistor for the speeds once already, and it’s failed again. It hasn’t even been two years. Why does it go bad, and can I do anything to prevent it? – Fan Frazzled

There are several different types of blower resistors used in vehicles, but they control fan speeds in one of two ways; either what’s known as pulse-width modulation or through resistance.

Pulse-width modulation is a fancy way of saying that the circuit is switched on and off quickly, reducing its average voltage. The longer it is “on” relative to “off,” the higher that average. This ratio is known as the duty cycle. While it once was only used for fans in automatic HVAC systems, it’s now common in manual systems, too. Electronic speed controls for blower fans typically have a sizeable aluminum heat-sink to keep them cool.

The second way of providing fan speeds is resistance, and, as you note, that is what’s used in your Cobalt. Every speed has its own circuit from the switch, and all but high speed goes to – and through – resistors mounted to a ceramic board that’s cooled by air from the blower. Each resistor reduces the voltage available to the fan by a different amount. (Older designs used metal coils for the same purpose.) Fortunately for you, this style is usually less expensive to replace.

There are several things that tend to kill blower resistors. Corrosion, from condensation or water leaks, and overheating because of restricted airflow due to a blocked cabin filter or debris ingested into the system, are the two that I commonly see.

Probably the most common reason though is excessive current being drawn from the fan motor. If the fan still works on high speed and isn’t noisy or slow, the issue won’t be obvious. Worn bushings and brushes can add enough current draw to overload the resistor.

If your resistor doesn’t have readily apparent corrosion damage, I’d suspect the blower motor is responsible for the failure. Note that Cobalts are oddballs in that you must cut the old motor out of its casing. The new one will bolt in place.

Bear in mind that while resistors are the most common failure in scenarios like yours, switches and connectors can also cause the same problems. A switch that feels odd may be damaged internally and any melted connectors will be obvious when they are inspected.

Ask a Mechanic is written by Brian Early, a Red Seal-certified automotive technician. You can send your questions to wheels@thestar.ca. These answers are for informational purposes only. Please consult a certified mechanic before having any work done to your vehicle.

Brian Early

Articles by Brian Early