• Let's Get Technical! - Shocks and Struts

    Posted on 20, September, 2017

                  With Shocktober just around the corner, we decided it would be a good idea to shed some light on your shocks and struts and what they do for your vehicle. Since the time before cars, when wagons and carriages plied dirt roads and cobblestone streets, something was needed to isolate the occupants from the jarring road. Springs were fitted to absorb some of the impact and keep the horse-drawn vehicles from hopping all over the road. Early cars used a similar setup, but as vehicles began to travel faster, something was needed to stop the bouncing action of the spring and to keep the tire in contact with the road.


    Enter the shock absorber. A shock absorber is an oil-filled tube that is designed to dampen the force of road impacts and spring oscillations. For many years, most cars and trucks came fitted with four shock absorbers, two in the front and two in the rear. They were a relatively simple affair and were only designed to move up and down. As suspensions became more complicated, a more integrated solution was required and the strut was born.


    While there are many variations in strut design, most incorporate the strut, spring and a mount into one assembly. On the top they connect to the body of the car, and on the bottom they connect to the front steering and suspension. Because they are connected to the steering system, they twist every time the wheel is turned and are a much more “active” part of the suspension than shocks are. In hard stops they reduce the tendency for the car to dive, shortening the stopping distance. On curves, lane changes and evasive maneuvers they keep the car under control and going in the right direction. In front wheel drive and all wheel drive cars (the majority of cars on the road), they also help to maintain traction at the drive wheels. 

    Shocks and struts absorb road forces and protect tie rods, control arms, sway bar links, ball joints and bushings from wear and fatigue.  Over 50,000 miles, a shock or strut will have moved up and down an average of 75 million times, even on good pavement. In Michigan that number may be, umm, a bit higher. Ride and handling degradation is something that happens gradually, but restoring your cars dampening system to new can make a marked difference. If the struts are actively leaking hydraulic fluid, they are providing little to no dampening.


    As they say in the old Monroe commercials, “Save the Squirrels!”

  • Let's Get Technical- Tires!

    Posted on 15, August, 2017

    This month we are going to take a closer look at the round black things that connect your car to the ground: tires! We tend to only think of tires when the snow flies, but summer is actually when we put the most miles on our cars and having good tires is important.


    Tires these days have many roles to play. The one we think of most of course is longevity, but there are other factors to consider when purchasing tires. Living in Michigan, we need tires that can handle rain, snow and ice, while still providing good handling on dry pavement and in the intense heat. That is a tall order for any tire, which is why two sets of dedicated tires, one for summer and one for winter, is ideal. But this presents cost and logistics problems and isn’t for everyone, so the next best thing is a good set of all season tires.


    Tread compound and tread design are the two components that are responsible for creating this happy medium. The compound must be hard enough to give a long life but soft enough to hold the road and give good traction when temperatures drop. The tread pattern determines how well the tire will expel water, slush and snow, as well as how the tire handles cornering and highway ruts. Tire manufacturers are always innovating and improving their designs, but will often continue to manufacture their older designs under private label brands. For example, Cooper makes Mastercraft tires, Firestone makes Fuzion, Goodyear makes Kelly and so on.


    In addition to the US and European brands that we are all used to, many of the larger Asian brands have come into the market over the past 10-20 years. Yokohama, Toyo and Sumitomo are long-standing Japanese brands, while Hankook and Kumho are long-standing Korean brands. All of these brands are used by domestic and import car manufacturers as original equipment on their new cars. The Finnish brand Nokian has had a small presence in the US market with their snow tires (after all, who knows winter driving better than the Finns?) but they are now trying to break in with their all-season and performance tires and there are some great deals to be had. Here at Kirk’s we are constantly evaluating new tires as they come on the market in an effort to determine which will be the best values for our customers.


    Even the best tires will wear out eventually, and it is important to know when that has happened or is imminent. The first thing to look at is tread depth. New tires come with somewhere between 10/32” and 14/32” of tread depth, depending on the type of tire. As the tread wears, the channels are able to dissipate less water, ice and snow, and by 4/32” their ability to work is greatly reduced. The wear bars on a tire are at 2/32” and are at this point considered “bald.” Sometimes a tire will wear evenly across its tread, and other times the outside edges or center tread will wear first. Outside edge wear, especially on one side only, is often indicative or an alignment or suspension issue. These issues can also cause feathering and cupping, both of which can lead to noise and vibration. Inside wear is often indicative of under-inflation. Did you know that tires tend to lose around 1 psi of pressure each month? They also gain or lose 1 psi for every 10-degree change in temperature, so it is important to check them whenever there are large swings.


    Miles are not the only thing that takes a toll on the life of a tire, they also wear out due to age. High heat, sub-zero temperatures, UV light and other environmental conditions will cause the rubber in your tires to break down. This wear usually presents itself in the form of dry-rotting and cracks in the sidewall or tread of the tire. Dry-rotted tires are at a greater risk of blowing out, so it is important to replace them. Tread compounds can also harden, causing reduced traction in poor weather.



    Finally, our wonderful Michigan roads can wreak havoc on the lifespan of our tires. Potholes can cause sidewalls to bubble or steel belts to shift, while nails, screws and other road debris can become imbedded in the tires. Impact damage is not repairable, but punctures can be, as the long as the damage is not to the sidewall of the tire. If a puncture is not too close to the side of the tire and is small enough, we can usually patch it from the inside. This is a permanent repair and is much preferable to a plug that goes in from the outside. If your tire ever becomes very low or even flat, do not drive on it! This can damage the tire further and may result in a repairable tire having to be replaced completely. We are working on a road-hazard warranty program that we will be offering soon through Kirk’s, so stay tuned!

  • Let's Get Technical- A/C!

    Posted on 12, July, 2017

    We are in the midst of A/C season here at Kirk’s and thought that now would be a good time to dig into that system a little. The A/C system in your car works in much the same way as the A/C in your home, as well as the system that keeps the food cold in your refrigerator.  The system operates by changing refrigerant back and forth between a liquid and a gas, absorbing heat and dissipating it. The journey starts at the compressor, which pressurizes refrigerant in gas form, sending it to the condenser, which lives at the front of the car, just ahead of the radiator. A cooling fan blows air across the condenser, turning that high-pressure gas into a high pressure liquid and dissipating the heat. The high-pressure liquid then travels to the receiver drier, which pulls any moisture out of it and sends it on to the expansion valve or orifice tube. The valve or tube (depending on the style of the system) turns the high pressure liquid into a low-pressure liquid, and sends it through the evaporator. The evaporator is located behind your dash and is what provides the “cool.” The blower motor inside the car blows across the evaporator, changing the low-pressure liquid into a low-pressure gas, while absorbing heat. The low-pressure gas is then sent back to the compressor to start the process all over again.  

    Also part of the system are pressure sensors that will shut the system down if pressures go too high or low, a temperature sensor to make sure the outside temperature is warm enough for the compressor to operate safely, and a temperature sensor to make sure that the evaporator isn’t icing up. Finally, because the compressor is operated off of the engine, there is a clutch that engages the compressor when the system calls for cooling, letting the pulley freewheel when there is no call.

    When your A/C stops blowing cold there are numerous things that could be causing it.  The most common problem is low or no refrigerant in the system, generally due to a leak. Refrigerant can leak from almost anywhere in the system; rubber hoses and o-rings degrade over time, seals on the compressor can give out, metal lines, condensers and evaporators can corrode or crack. Once we have determined that the system is low on refrigerant, we will look for any obvious signs of leakage or breakage. If everything looks okay, we will evacuate whatever refrigerant is left, pull a vacuum and add the correct amount of refrigerant. We will also add a UV dye to help us detect any leaks.

    Other common problems are compressor clutches that wear out, pressure and temperature switches that go bad, and complete compressor failure. In the latter case, the compressor will often release debris into the system as it fails, necessitating a flush of the system and sometimes replacement of clogged parts.

    Even when your A/C system is functioning correctly, it is only designed to drop the temperature at the vents in your dash by 40 degrees or so.  So if it is 100 degrees outside, your A/C might not be working as well as you think it should! Humidity also effects your A/C’s efficiency.

    One last little tip: when using your A/C in hot weather, keep it on recirculation mode (or MAX mode depending on your system). This closes the fresh air intake and recirculates the already cooled air in the car. Turning into a closed system also allows the fan to blower stronger, getting every last bit of cool into your cabin. We hope you enjoy the rest of your summer in comfort! 

  • Let's Get Technical- All About Oil!

    Posted on 03, May, 2017

    In the last newsletter we talked about the fuel system in your car and how to keep it clean and functioning well. This month we’re going to get into the simplest but most important fluid in your car: Oil! Oil can generally be broken down into three categories: conventional, synthetic blends and full synthetic. Conventional oil is made from the good old “crude” oil that you see being pumped out of the ground and is also used as the basis for gasoline, among other things.  But synthetic oil can also be made from crude oil. Huh? Doesn’t synthetic mean “synthesized” or man-made? Technically yes, but a court case a number of years ago allowed oil companies (specifically Mobil) to advertise their oils as synthetic even if some or all of the base oil was conventional crude. The argument was that the oil companies could process crude oil to the point of being very similar in structure and durability to a real synthetic, and should therefore be allowed to label it as such. So now, most synthetic oils, at least in the US, are made from highly refined crude oil bases, with more processing and additives than their conventional counterparts.


    So is “fake synthetic” oil really any better than conventional? Absolutely. It is more refined, has more and better additives and can maintain its proper viscosity (oil weight), sheer strength (ability to protect) and detergents (ability to clean) for longer and in harsher conditions than conventional can.


    Does anyone make a “real” synthetic anymore? Yes. Most oil companies will make their oils to meet the specifications of the many car manufacturers. If an oil company can’t meet a manufacturer’s specification with an oil that has a crude base, they have no choice but to use a fully synthetic base. Most oils that meet the specifications for European cars are made from fully synthetic bases, partly because of the manufacturers’ requirements, but also because the labeling laws are different than in the US.


    Synthetic blended oils are best thought of as an oil that is more refined and has better additives than a conventional oil, but not enough to be called a “full synthetic.”


    What type of oil should you put in your car? Whatever the manufacturer recommends. Most car companies will specify an oil weight (5w30, 5w20, etc) that meets their specifications. As long as it meets those specifications, they don’t generally care if the oil is conventional, blended or a synthetic. One of the more well-known specifications is the GM Dexos specification. It applies to almost all GM cars made since 2010. There are synthetic blend oils that meet this specification and there are full synthetic oils that do as well. The Dexos oil that we use is a full synthetic, because the price difference is negligible and we like the extra refinement of the full synthetic.  If your car calls for a 5w-20 oil, a synthetic blend oil will most likely meet its specifications. If your car calls for a 0w-20 oil, the only oils available to meet its specification will likely be full synthetics.


    If all this sounds like Greek to you, fear not! We keep track of all vehicle and oil specifications, and always make sure your car is getting the right oil. Now for the age-old question: How often should I change my oil? We like to keep this part simple. If your car is using a synthetic blend or conventional oil, change it every 3000 miles. If your car is using a full synthetic oil, change it every 5000 miles. We understand that some cars have oil monitoring systems that tell you when to change your oil, and some manufacturers say you can go up to 10,000 miles on an oil change. We just don’t trust it. Sure, call us paranoid, but the oil life monitoring system on your car isn’t analyzing the actual oil, it is basing its assumptions on a theoretical set of ideal conditions. And 10,000 miles is just crazy. Is that city or highway? A lot of short trips? The manufacturers don’t know, and we don’t either. Could the oil theoretically still do its job that long under ideal conditions? Possibly, but can the filter? Once the filter is full, it is bypassed and is no longer removing contaminants from the oil. There are too many unknowns for us to be comfortable with extended oil change intervals. Car manufacturers are in a continuing quest to lower the cost of operation of their cars as a selling point, but regular maintenance will pay dividends in the long run. Cars today last longer than ever and we’d like to see yours on the road for as long as possible. Oil is cheap, cars are not.

  • Summer Car Car Tips

    Posted on 27, July, 2014

    Summers here! Is your vehicle ready for the hot Michigan weather?

    Here are 9 easy things you can do yourself to get your car ready for the warmer weather:

    1.Clean your vehicle

    Prevent rust by giving your vehicle a thorough cleaning to remove salt and sand accumulated over winter. Clean under the hood, shampoo the engine, as well as wheel wells. Wax and polish your vehicle at least twice a year to preserve its paint.

    2. Lights

    Make sure headlights, brake, reverse, parking, turn indicators and hazard lights are working properly. Check the small bulb above your license plate.

    3. Block heater

    Tuck away the block heater cord.

    4. Batteries

    Sometimes a hot summer can limit a battery’s lifespan. Even a boost cannot be relied upon to keep you going. Fix the real problem. Kirk’s Auto Care can test your battery, or you purchase a new one if needed.

    5. Brakes

    Road salt from the winter driving months can lead to brake damage. Your brakes should be checked every six months or 12,000 miles.

    6. Tires

    Make sure your tire pressure is within factory specifications. The vehicle’s owner’s manual will have recommendations. The information can also be found on the door jam or glove box.

    7. Wipers

    Wiper blades are critical for safety, but have a short lifespan – six months. Check the blades and replace if they are worn or damaged.

    8. Oil change

    Change your oil regularly and keep fluids like brake, coolant and windshield washer, topped up.

    9. Cooling system

    Be sure to check for leaks in the radiator and for cracks, leaks and swelling in the rubber cooling system hoses. It’s also wise to replace the antifreeze if it’s more than two years old