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A Closer Look at Crankshafts
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By Counterman
Stabilizer bars. You may know them as sway bars or anti-sway bars. You may know them as roll bars or anti-roll bars. They’re all the same thing, and it’s generally understood they improve handling … but how?
Any time a vehicle is turning, the forces that act upon it cause the body to roll, sway or tip away from the turn. It’s the laws of physics at work. In extreme situations, these forces can cause a vehicle to tip over, though that’s generally only the case with taller trucks and vans, and rare at that. You really have to be moving for that to occur. The real factor is how they negatively affect handling and how a stabilizer bar can prevent it from happening.
Picturing this “tipping” affect helps us understand how a stabilizer bar works. When driving in a straight line, the weight of the vehicle is evenly distributed between left and right. In a turn, as the vehicle body leans, it shifts the weight to the tires on the outside of the turn, compressing the suspension on the outside in the process. This shift in weight causes a loss of traction on the inside, resulting in poor handling and potentially the loss of control.
A stabilizer bar connects one side of the suspension to the other. They can be located in the front, rear or both. They’re mounted to the frame or body with brackets and bushings, and connect to the suspension at the control arms or struts. The connection at the suspension can be a bracket and bushing or a link, which is the most common today.
When any suspension movement occurs, that movement is transferred into the stabilizer bar, which then is transferred through it to the suspension on the other side. This balances the compression of the suspension on both sides, eliminating body roll, balancing the weight distribution of the vehicle and providing optimum traction and handling.
You’ve likely heard the terms oversteer and understeer. Understanding and controlling them is one of the most important aspects of performance driving, and it’s an important aspect of new-car design. They’re relevant in this context because both are affected directly by the action of the stabilizer bar.
For this reason, adding or changing stabilizer bars is a common practice for those who look to improve the handling performance of their car. If you increase the stiffness of the rear stabilizer bar or decrease the stiffness of the front, you reduce understeer. If you increase the stiffness of the front stabilizer bar or decrease the stiffness of the rear, you reduce oversteer. Someone who is building their car for performance or racing will spend hours on stabilizer-bar adjustments alone until they “tune” the handling of their car.
For many years, sway bars were just an option, or only located in the front. But due to the improvement in handling they provide, most of today’s cars and trucks have them.
Stabilizer bars are just a piece of metal. Some are a solid bar, some are hollow. Each one offers different performance aspects in how much they twist versus how much force it can transfer to the other side of the suspension. In addition, performance stabilizer bars and/or their connecting links often are adjustable at each end to provide an additional range of tuning.
One drawback associated with stabilizer bars is they can affect the overall ride quality of a vehicle. The stiffer the sway bar, the better a vehicle may handle – but the worse it will ride. In trucks and SUVs, the sway bar limits suspension travel, which is a drawback to those who use them for off-roading.
Leave it up to technology to take it one step further with active and electronically disconnecting stabilizer bars. Active stabilizer bars are found on some luxury performance cars. They work by using an electric motor and gears to vary the stiffness of the stabilizer bar when needed for cornering. The ability of these systems to make instant corrections is nothing short of impressive with the outstanding handling characteristics they make possible.
Electronically disconnecting stabilizer bars – popular on some new trucks and SUVs – use gearing similar to that in a manual transmission to physically disconnect the two halves of a stabilizer bar to allow maximum suspension movement. They will reconnect only once the vehicle is on level ground. Stabilizer bars are a fundamental part of suspension design and operation, and technology has made them even better. That’s something we all can “handle.”
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By Counterman
Platform-sharing” and “badge engineering” are terms often used to describe the common industry practice of developing multiple vehicle models from a common design. The economy of a single design underpinning multiple vehicles allows manufacturers to streamline the development process, and to provide the buyer with options across their base, mid-line and luxury divisions. Much of this “twinning” occurs within a manufacturer’s “family” of brands, but cooperating with rival manufacturers already well-established in a market allows the manufacturer to produce vehicles outside their wheelhouse.
Ford Motor Co. has a long history of platform-sharing among its Ford, Lincoln and Mercury divisions, in addition to several collaborations with outside OEMs. As a global company for more than 100 years, Ford’s U.S. arm also has benefitted from the engineering of its European, Australian and Asian divisions.
Since its establishment in 1939, Mercury was positioned as Ford’s mid-range division, filling the price gap between the Fords and Lincolns. Mercury served this role until 2010, when the division was shuttered. The last Mercury rolled off the assembly line in January 2011. That final Grand Marquis had shared the Panther platform with the Ford Crown Victoria and the Lincoln Town Car – two models that also would be discontinued later that year. Prior to its closure, Mercury also had offered mid-range versions of the Mustang (Capri), Taurus (Sable), Escape (Mariner) and Explorer (Mountaineer).
Rebadging the Explorer has been a cottage industry for Ford. In addition to the Mountaineer, Lincoln offered the Aviator from 2003 to 2005, the MKT from 2010 to 2019 and the Aviator again beginning in 2020 (now based on the latest Explorer CD6 platform). After prior collaborations on Ford’s Courier and Ranger pickups, Mazda also was an early adopter of the first-generation Explorer platform. The Mazda Navajo was built alongside the Explorer in Louisville, Kentucky, from 1991 to 1994. Mazda and Ford later would co-develop the Tribute and Escape for 2001.
This kind of sharing hasn’t always been the case at Ford. At the end of World War II, Ford of Canada divided up its dealer networks, establishing standalone “Ford” or “Lincoln-Mercury” dealers throughout Canada. An unforeseen outcome of this separation was that the Lincoln-Mercury dealers did not have economy models or trucks. In 1947, these dealers received the first of the “M-series” trucks, which essentially were re-badged F-series Fords. A budget line of “Meteor” passenger cars was introduced in 1949. Ford dealers received the “Monarch” line of mid-priced vehicles to fill the gap in their own lineups. This arrangement continued until the 1960s, when tariffs on vehicle trade across our northern border were eliminated.
Mercury trucks were never sold in the United States, but in 1993, Mercury buyers were offered their first minivan, the Villager. This actually was a joint venture between Ford and Nissan, with Nissan-badged versions carrying the Quest nameplate. The Villager was assembled by Ford, but featured a 3-liter Nissan FWD drivetrain. It later would be replaced by the Windstar, which had no equivalent Mercury companion model at the time. The Windstar was renamed the Freestar for 2004, and regained a Mercury companion in the Monterey.
Lincoln, founded in 1917 and purchased by Ford in 1922, still represents Ford’s luxury division. Long known for large cars like the Continental and the Town Car, Lincoln in 2021 transitioned exclusively to crossover and SUV platforms. Lincoln had even tried its hand at pickup trucks, with the 2002 Blackwood, and the 2006-2008 Mark LT. Both were rebranded luxury versions of the F-150 crew cab platform.
In 2007, Lincoln adopted a new model-naming convention, playing on the heritage of the “Mark-series” nameplate used through 1998. The MKX and MKZ were the first of these, with the MKZ sedan being the Lincoln version of the Ford Fusion and Mercury Milan, and the MKX being a Ford Edge-based crossover (“X”-over). Originally intended to be spoken as “Mark-X” and “Mark-Z,” both vehicles were produced on the same CD3 platform originally developed for the Mazda 6. The MKS sedan (based on the Taurus) and the full-size Explorer-based MKT followed in 2009 and 2010, respectively.
In 2015, the MKC compact crossover was introduced, built on the Escape platform. Lincoln has since dropped the “MK” designations in favor of proper names for its crossover and SUV lineup, which is a relief to anyone who has misheard or misspoken these similar-sounding model names while looking up parts!
Ford-Lincoln-Mercury (FLM) dealerships once were a common sight here, with all three divisions available in one location. But, after a decade without Mercury, Ford-Lincoln dealers are fracturing yet again. In 2019, Lincoln began an initiative to develop standalone Lincoln dealerships to market more exclusively to the upscale clientele of the luxury-car market. Targeting 30 U.S. metro areas, Lincoln-only showrooms have already opened in half of the roughly 150 planned locations. Sales are up at these dealerships, but they still don’t have pickup trucks!
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By Counterman
rack: noun
1. The linear component of a rack and pinion gearset.
2. The short name given to a rack and pinion steering assembly for an automobile.
This is one of those times when the same word is used over and over to describe two things that are related but different. When I first learned about rack-and-pinion steering, it was anything but new. Nonetheless, in my world, I was used to traditional. I was among the guilty who shunned things that in no way could ever be better than a carburetor, points, condenser and crank windows.
When it came to steering, if it didn’t have a steering box, pitman arm, idler arm and a center link, it probably wasn’t a real car.
You laugh, but now, so do I. Automotive technology always has changed for the better, and rack-and-pinion steering just made sense. It was simple, less expensive, lighter-weight and simple to maintain. The term “rack and pinion” describes a type of gearset that transfers rotational motion into linear motion. In the case of an automotive application, the rack-and-pinion gearset is housed in a unit that we simply refer to as the steering rack, or rack for short.
So, a steering rack transfers the rotational motion of the steering wheel into the linear motion required to move the tie rods left or right for steering. They initially became commonplace on small economy cars and were additionally well-suited for front-wheel-drive applications due to the limited space they require. Now, almost every new car, SUV and light truck on the market has rack-and-pinion steering.
A simple design and low maintenance are benefits of a steering rack, but that doesn’t mean they haven’t caused a headache or two over the years – and there are many questions you’ll still field about these systems. While they’re too difficult to describe, the service aspect is where you’ll get most of the questions, and this is where your customers will benefit from your knowledge. After all, as a counter professional, you’re in the business of answering questions.
Many early steering racks on small cars were simple manual racks with no hydraulic assist. These were my favorite. They rarely developed any problems and, in many cases, would last the life of the vehicle. Then, cars got heavier, people got softer and hydraulic power steering for the most part became standard. Today, electric power steering is taking over, and in many ways with the lack of a hydraulic pump, hoses, lines and leaks, it has brought back the simplicity of the original manual rack.
Although many aspects are the same regardless of the type of assist, in this article I’m going to focus on hydraulic power-steering racks. They’re still going to be around for some time, and service considerations are where you’ll get most of your questions. Making sure the job is done right is important for not only safety and efficiency, but it also helps prevent unnecessary warranty hassles.
First and foremost is power-steering fluid. It’s commonly overlooked and neglected. The valving and seals inside a hydraulic power-steering rack rely on clean fluid for proper operation, and just like any other fluid service, ignoring this can shorten the life of the steering rack. When replacing a rack, fluid should be drained and flushed as best as possible, and it’s a good idea – as well as a good upsell – to install an inline filter. Most of these types of filters work with a magnetic mesh that’s especially beneficial to trap small metal particles.
One of the most common problems to arise is a torn rack boot. These rubber bellows-style boots expand and collapse every time you turn the wheels, and it’s just unavoidable that they eventually wear out. There are two immediate problems with this. One, the inner tie-rod ends will collect dirt in the grease that lubricates them, and two, dirt and debris will be drawn into the rack seals every time you turn, eventually causing damage and leaks.
link hidden, please login to view Torn boots should be replaced as soon as possible when they’re discovered, and the vast majority of them require the removal of the outer tie-rod end. An alignment is required afterward – no ifs, ands or buts.
Worn inner tie rods are another common problem, and while “technically” not part of the steering rack, service procedures can affect the integrity of the rack. Many new racks come with new inner tie rods and boots pre-installed to prevent damage from incorrect installation, so the boots keep everything sealed up from the start.
Most of the time, replacing the inner tie rods requires a special tool, kind of like a deep socket on steroids – deep enough to reach over the length of the tie rod and access the inner end where it bolts to the rack. On the end of the tool is a half-inch square drive. The factor to be aware of is that by-the-book service procedures call for holding the rack (the actual internal component) in a soft jaw vise when removing or installing the inner tie rod, so you don’t twist it and risk damaging the pinion gear.
The problem is in practice, this is rarely done because there’s no way to do it with the entire assembly installed in the car. There’s simply no access to get any type of holding fixture onto the actual rack. For fun, I looked up the top videos on the internet for installing inner tie-rod ends, and none of them mention holding the rack. Perhaps because they don’t want you to know they didn’t do it, or they don’t know the solution because there really isn’t a good one – at least not one I’ve learned of yet.
You might be able to get locking pliers clamped onto the rack to hold it, but that would gouge the machine-finished surfaces and tear up the rack seal, so that’s out. So, how serious is the problem? Most inner tie rods don’t require very high torque, and many of them use a type of thread locker, a locking nut or a type of retainer to prevent loosening. The bottom line is, if you use hand tools to loosen and tighten the inner tie rod, and slowly torque it to the correct specification during installation, the pressure against the pinion is going to be minimal, and damage is unlikely.
Whatever you do, use hand tools. Do not use an impact wrench on the end of the inner tie-rod tool. This will transfer a series of blows directly into the pinion and the valve assembly inside the unit, and you could be asking for trouble.
As mentioned before, any time the rack or a tie-rod end is replaced, an alignment will need to be performed. But, just as important is any time the rack is being replaced, the steering shaft will be disconnected. Always make sure the steering wheel isn’t allowed to spin free, or the airbag clock spring will be damaged. Also, make sure the rack is in its centered position before initially disconnecting the steering shaft and before reinstalling it.
Quite possibly the most useful tip for new steering-rack installation involves cleaning the splined steering-shaft connection. It’s a precision fit. In other words, both sets of splines need to be perfectly clean. If they are, they’ll slide right together. If not, you’ll fight it forever. Many new (or remanufactured) racks are painted, and it’s not uncommon for overspray to get on the splines. This may seem inconsequential, but the thickness of the paint is enough to cause a nightmare.
There are many opportunities for upsells with steering racks and related services. Outer tie-rod ends are often replaced one at a time and, in many cases, this is all that’s needed. Still, it’s a good reminder to check the rack boots and other ends closely. Since an alignment will be required, it’ll save money in the long run to take care of any pending issues now.
If you’re replacing an inner tie rod, you’ll already have the outer and the boot off. It’s often much easier to replace them too. Brake/parts cleaner is a good solvent for cleaning out reservoirs and lines, but make sure they’re allowed to completely dry before sealing the system up. I like to use clean power-steering fluid as a final flush to make sure any trace of solvent is gone, so selling a little extra is a good idea.
Tool upsells can include the inner tie-rod tool, an outer tie-rod separator and a grease gun if grease fittings are included on any of the front-end components.
The crowning touch is service information for torque specifications and bleeding procedures. Everyone should have a manual, and you’ve got them on the shelf, right? This is the perfect job to recommend one.
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By Counterman
If you were to ask a Subaru owner, they may tell you that their world is flat. No, I don’t mean that they think the earth is flat. It’s a clever euphemism for the distinctive engine design used by Subaru: the flat, or boxer engine. The boxer engine is to Subaru what the V-8 is to muscle cars. You may have seen a T-shirt or decal somewhere with the icon below. It’s an illustration of a crankshaft and pistons from a boxer engine.
But there’s so much more to this automaker than its distinctive engine types. Let’s take a closer look at what makes Subaru so special, and what makes it tick as a brand. After that, we’ll look at a few common repairs so you’re prepared to help your customers find the part they need to get their vehicle back on the road again.
Flat Engines vs. Boxer Engines
Subaru engines are often misunderstood. People commonly refer to them as flat engines, but this isn’t the case. There’s one major difference in the construction of these two types of engines.
Both flat engines and boxer engines will have cylinders on either side of a central crankshaft, but the crankshafts are different in each engine type. A flat-engine crankshaft will mount two opposing connecting rods onto a shared crank pin (Figure 1), whereas a boxer engine will mount each connecting rod onto its own separate crank pin (Figure 2).
This subtle difference in construction affects the way the pistons move inside the cylinders. In a flat engine, one piston will move inward while the opposing piston moves outward. In a boxer engine, each opposed pair of pistons will move inward and outward at the same time.
Boxer engines produce significantly lower vibrations when compared to other engine configurations. Since each opposing piston is moving in and out at the same rate and speed, the opposing forces are canceled out. This means that they don’t require counterbalance shafts to smooth out their operation, and the internal components don’t suffer from the same sort of wear and tear caused by vibrations.
Boxer Engines
Boxer engines offer a number of advantages over other engine styles. (It wouldn’t make sense for Subaru to keep installing these engines into their vehicles if that wasn’t the case.) First and foremost, the boxer engine is incredibly compact. It’s effectively a V-4, with two cylinders on each side of the central crankshaft. This means that the overall length of the engine block is only a little bit over the length of two cylinders.
Boxers also are compact vertically, so they can be mounted lower in the engine bay. This pays dividends when you consider the center of gravity in the vehicle. The engine tends to be the heaviest component in the front of the vehicle. If the engine can be mounted lower in the vehicle, it lowers the center of gravity. This leads to better driving dynamics, better stability in corners and reduced understeer (Figure 3).
Understeer is a phenomenon that causes the vehicle to not turn as sharply as intended. Have you ever put a 24-pack of drinks in the front of a shopping cart, then tried to turn the cart at the end of the aisle? That’s understeer.
As I said earlier, boxer engines produce less vibration than other engine styles, and don’t require any additional counterbalancing to operate smoothly. And last but not least, they produce a truly distinctive exhaust note. Seriously, it’s music to the ears. Well, that may be the car enthusiast in me speaking.
Now, all of these advantages aside, there are a few drawbacks.
The engine assembly is rather complex, both during manufacturing and when rebuilding later on down the road. In an inline or V-style engine, you can place the crankshaft into the main bearings, torque the main bearings, then install and torque the connecting rods onto the crank pins. All of this can be done from underneath the engine with relative ease.
Boxer engines use a crankcase that’s split into two pieces. You can’t access the crankshaft to torque down the connecting-rod caps once the crankcase has been put together. So, the connecting rods must be installed and torqued down onto the crank pins with the crankshaft supported outside of the engine. Then the entire rotating assembly is installed into the crankcase. Or is it?
Nope! The pistons need to be installed onto the connecting rods AFTER the two halves of the crankcase have been bolted together. There are special access holes in the front and back sides of the block that allow you to slide the wrist pins into place (Figure 4). There are a few common issues in boxer engines once they start to age, but we’ll come back to those later on.
Symmetrical All-Wheel Drive
If there’s one other thing that Subaru is known for, it’s the all-wheel-drive system. Known as Symmetrical All-Wheel Drive (SAWD), Subaru has been perfecting the art of driving all four wheels for decades. SAWD was first introduced in 1972 as an optional part-time four-wheel-drive system on the Leone wagon. This early four-wheel-drive system was all-mechanical, and has evolved into the more electronic SAWD system that we know today (Figure 5).
Modern SAWD systems work in conjunction with the vehicle dynamic control, antilock brakes and traction control for optimum handling performance and grip. Subaru has earned a reputation as one of the best vehicles to drive in snowy conditions, or offroad adventuring thanks to the superior grip and stability offered by SAWD. I’m willing to bet that you’ve seen a Subaru Outback with a suspension lift, big offroad tires and a roof rack out on the road. In fact, it’s not uncommon to see Outbacks, Foresters and Crosstreks set up for offroad adventuring out on the road today.
Safety
Subaru’s commitment to safety has led to years of industry-leading advancements in both passive and active systems. A precision-engineered, strong vehicle frame will provide maximum protection for passengers in the event of a collision. Subaru’s advanced airbag systems can deploy up to eight airbags, protecting the passengers from forces in all directions (Figure 6).
In other vehicles, the engine and/or transmission may be pushed inside the passenger compartment during a front-end collision. But, thanks to the compact size and placement of the boxer engine, the drivetrain is pushed downward and away from the passengers in a Subaru (Figure 7).
It’s clear that Subaru’s commitment to safety has paid off. A cursory glance at the IIHS website shows strong ratings for all of its current models. In fact, Subaru earned Top Safety Pick or Top Safety Pick+ ratings on the following 2022 model-year vehicles:
• BRZ (Top Safety Pick+)
• Crosstrek (Top Safety Pick)
• Crosstrek Hybrid (Top Safety Pick+)
• Impreza (Top Safety Pick)
• Legacy (Top Safety Pick+)
• Outback (Top Safety Pick+)
• Forester (Top Safety Pick+)
• Ascent (Top Safety Pick+)
The only model missing from this list is the WRX. It appears that the 2022 WRX hasn’t been crash-tested at the time of this writing. Based on Subaru’s track record, I wouldn’t be surprised to see the 2022 WRX also earn its place on this list in the near future. I went back 10 years on the IIHS website and saw consistent top safety-pick ratings for the brand throughout the past decade.
In addition to these strong crash-test ratings, Subaru has pioneered several advanced driver-assistance systems (ADAS) to help drivers avoid collisions whenever possible. The EyeSight system uses a series of cameras to scan the road ahead of you (Figure 8), and apply the brakes if needed to avoid or minimize a collision. Subaru’s DriverFocus system looks for signs of a distracted or drowsy driver, much like an attentive front-seat passenger might do. And of course, Subaru offers other ADAS systems for added safety and convenience including blind-spot detection, rear cross-traffic alert and reverse automatic braking just to name a few.
Motorsport
I’d be remiss if I didn’t mention Subaru’s strong racing heritage. Subaru has proven itself in the racing world by pitting its engineering and manufacturing skills against the competition. And of course, Subaru’s success on the racetrack has led to advancements in its road cars.
If you want to get a closer look into the Subaru racing world, I highly recommend searching for a video series called “Launch Control.” This show follows the Subaru Racing Team USA (SRTUSA) season after season. You’ll see driver profiles and background, vehicle development and the challenges that come along with running a race team.
Common Issues
As with all things that are mass-produced, there are some common failures you should be on the lookout for. If a customer walks into your store with a question about their Subaru, you may be able to help them find exactly what they need to perform the correct repair and keep their vehicle on the road for as long as possible.
Due to the design of the boxer engine, the cylinders are mounted horizontally on either side of the crankcase. This orientation means that any sediment, debris or contaminants that might be present in the cooling system will settle down inside the coolant jackets instead of elsewhere in the system. The same thing will happen with the oiling system. Over time, this can cause the head gaskets to leak, leading to oil and/or coolant consumption, leaks and abnormal smoke from the tailpipe.
This is an issue that has garnered a lot of attention on social media and other channels, but it’s not a guaranteed problem with every single Subaru engine. Routine maintenance such as oil changes and coolant flushes can help to extend the life of the engine and all of its components. There are two types of head gaskets that will be found inside the boxer engine: composite and multi-layer steel (MLS). If the customer removed a composite gasket from their engine, an MLS replacement gasket can be seen as a more robust option. MLS gaskets are more wear-resistant and can offer an extended service life over composite gaskets.
It’s not uncommon to see oil leaking from a high-mileage boxer engine, or any other style of engine for that matter. While not overly common, valve-cover gaskets, camshaft seals and rear main seals tend to be the most likely sources. If the engine-oil level drops between services, but there are no external leaks present, it’s time to look inward. Worn turbo seals, piston rings or a faulty PCV system can cause oil consumption.
The all-wheel-drive system in Subarus can be vulnerable to unintended drivetrain movement or free play. For example, a worn pair of engine mounts could cause the drivetrain to shift from side to side while driving. This places added stress onto other components such as CV axles and bearings. If a customer is in your store asking about a replacement CV axle, try to help them figure out what caused the axle to wear out in the first place. You may be able to help them to treat the cause, not the symptom.
Timing belts and water pumps are routine maintenance items on boxer engines. Replacement intervals vary based on the model and the production year; be sure to check the OE service information for specifics. We suggest selling a complete timing-belt replacement kit with the belt, water pump and all other required components to get the job done.
Finally, be on the lookout for worn, cracked rubber hoses in the engine bay. Years of heat cycling will cause rubber hoses to break down, become brittle and crack. The same goes for plastic components such as radiator end tanks, reservoirs, plastic hose fittings and more.
It seems to me that Subaru has found a winning formula, and the automaker continues to stay true to it. I’m excited to see what the next decade will bring for this pioneering Japanese automaker.
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By Counterman
The cooling system no longer is focused on cooling as much as it is on managing and maintaining a consistent engine and transmission temperature. Since our industry always seems to find a way to inundate us with new acronyms and terminology with every model year, it could be only a matter of time before they start to call it a Powertrain Heat-Management System (PHMS).
Make no mistake: The name is not real – at least not yet. I just made it up. But it’s a very accurate representation of what a modern-day cooling system does. To understand the technology of today’s cooling system and why the name almost deserves a change, let’s first look at a brief history mixed with a touch of science.
The term “cooling system” originally came about on the early automobile, and that’s exactly what they did. However, the early cooling systems were … simple. Scientifically known as “thermosyphon systems,” the hot coolant in the engine rose upward into the top tank of the radiator. As it cooled, it fell to the bottom of the radiator, where it then would flow into the engine block. The result was a continuous circulation of coolant through the engine, requiring no water pump or thermostat to make it work.
Although the early cooling system worked well, it had no choice but to evolve, as engines got bigger and became more powerful. If you think about an engine on a scientific basis, it’s nothing more than a way to convert heat energy into mechanical energy. Basic logic tells us that the more power an engine produces, the more heat is generated that must be removed.
Since cooling systems needed the ability to remove more heat, they quickly evolved into utilizing water pumps and thermostats. Thermostats always have had two purposes. First, the engine coolant must remain in the radiator long enough to transfer its heat to the air. When the thermostat is closed, it allows sufficient time for this to occur, and when it opens, the coolant flows into the engine and is able to absorb heat to begin another cycle.
Second, engines need to operate near the boiling point of water. Why? Because water is a byproduct of combustion, and this high operating temperature ensures that water is evaporated from the engine oil during operation. Without the thermostat set to keep things hot, the engine oil cannot burn off water and will quickly become contaminated.
Cooling systems, even as we entered the era of fuel injection and electronic management, remained fairly simple at first. But we knew that engine temperature was directly related to fuel economy, emissions and power output, and that maintaining that temperature where we wanted it was a necessary step to achieve our goals in those areas.
It didn’t take long before the need for precise engine-temperature control became a prevailing factor affecting both engine and cooling-system design. Many components that we thought would never change began to receive a full dose of technology. Here’s a look at how things are shaping up for the future.
Thermostats
While not an everyday item yet, electrically controlled thermostats are being utilized in some applications, and I expect we’ll see an increase in this. The ability of an internal-combustion engine to achieve maximum fuel economy, minimum emissions and maximum power occurs at slightly different temperatures for different operating conditions. By adding this additional level of precision to temperature control, we can match temperatures to operating conditions, increasing power output and fuel economy.
This need for precise temperature control is why modern fuel-management systems monitor coolant temperature and if there is any deviation outside of the expected norm, a very common diagnostic trouble code (DTC) is P0128 (“Engine Coolant Below Regulating Temperature”). As time goes on, we can only expect this to become a parameter that’s much more closely monitored.
To further illustrate the advantage of an electronically controlled thermostat, consider traditional (old-school) thermostat operation. As the engine warms up, the radiator and hoses remain cold. When monitoring cooling-system performance as a technician, it’s common to keep a hand wrapped around the upper radiator hose. It stays cold until the thermostat opens; then it gets hot really quickly as the coolant flows from the engine into the radiator.
Then we use our hands to feel the radiator tanks warming up, and when they do, we then expect that the electric cooling fans (if equipped) are due to come on within a few moments, and we often move our hand into the path of the air coming off of the cooling fan to sense the volume of airflow and amount of heat being drawn off the radiator. Hi-tech is watching the engine temperature on a scan tool while this happens.
The point of this? The overall process of heat transfer is slow, and extreme precision is not possible with a traditional thermostat. As a result, the most advanced engine-management systems are looking ahead at engine temperature based on throttle position and calculated load, so that they can precisely manage engine cylinder and head temperature, effectively managing combustion efficiency. It’s impressive. Electronics and electronic thermostats make it all possible.
Water Pumps
What could possibly change about water pumps? That’s what I used to think, but they are changing. As effective as a traditional belt-drive water pump always has been, if we look at them from an old-school operational standpoint, as we did thermostats, we begin to see the flaws in their operation. Traditional belt-drive water pumps run the whole time at the speed of the engine, but with modern temperature-management technology, it’s not necessary for them to run constantly. Not only does this create an unnecessary drag on the engine, but it also can reduce the accuracy of precise temperature control.
By redesigning the traditional water pump and adding electric water pumps into the system, unnecessary drag is eliminated, and the engine-management system is able to generate coolant flow when needed, as needed. This can help reduce warmup time and also improve overall temperature control.
Electric water pumps also have the advantage of remote locations in engine compartments, which is beneficial as space becomes more and more constricted, and they are utilized for after-run features to help cool components such as turbochargers.
Cooling Fans
Electric cooling fans are not new by any means, but they no longer are a simple on-or-off type of fan. Early fans often employed a resistor to create both a low- and high-speed option, but many of today’s fans are pulse-modulated variable-speed fans that again give the engine-control module the ability to match fan speed with other operating conditions.
Active Grille Shutters
The newest member of the cooling-system technology family is the active grille shutter. Many manufacturers are utilizing this technology on certain vehicles, which, as you might have guessed, looks just like a set of shutters over some portions of the radiator. This can improve vehicle aerodynamics as well as decrease warmup times. They only open when needed to allow for additional cooling.
Heater Cores
Heater cores are part of the cooling system. Even though they don’t generally affect system function in the terms of engine-temperature management, inadequate heat stemming from a restricted heater core is a common complaint. But a restricted heater core is sometimes misdiagnosed as a bad thermostat or vice versa. And some vehicles utilize an electric water pump specifically to move coolant through the heater core. If the pump is bad, it could be misdiagnosed as a restricted heater core. Cooling-system diagnosis always should take into account the ever-increasing complexity of HVAC systems.
Electric Vehicles
Just when you thought there couldn’t be any more, hybrid and electric vehicles are bringing additional changes. Did you ever think you would see a high-temperature radiator and a low-temperature radiator? Plus, a water-cooled air-conditioning condenser? You’ll start to see them on electric vehicles.
You also can throw in some valving and a high-voltage coolant heater to boost heater-core output, plus a completely different cooling circuit for the batteries, power inverter, transaxle and electric motor. The good news for us? There’s a lot more to fix and a lot more parts to sell.
So, when will they start to call it a PHMS? And I’m waiting for the day of GPS-monitored temperature-sensing microchips that float around the cooling system, reporting the exact temperature of the coolant along the way. Sound crazy? Probably. But if it ever happens, just remember where you heard it first.
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