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Vehicle Maintenance Remains Key: How to Keep Up

Keeping up with Changes is Critical

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Filling a hybrid vehicle inverter cooling system after inverter replacement.

Maintenance might be one of the least exciting topics of automotive repair; at the same time, it is likely the most important. If you have been a technician or service advisor for any length of time, you probably know a lot about auto maintenance. That doesn’t mean you do not need to keep up with the changes though. With auto manufacturers using new materials, fluids and constantly changing technology, the way we maintain vehicles is changing, as well. The point of this article is not to bore you by repeating what you already know or try to emphasize why auto maintenance is important (I am sure you are well aware), the purpose is to keep you up to date with modern vehicle maintenance changes.

It seems like almost all the changes in how we maintain modern vehicles can be put into one of three categories:

New or better fluids

New and different materials

New technology

Several systems or components might fall into more than one of these categories. Here are what I believe to be the biggest changes to vehicle maintenance needs in recent years.

New or better fluids

The majority of vehicle maintenance has been and still is maintaining the many different fluids used. With better-made vehicles and better fluid technology, when and how we maintain these fluids has changed. When determining fluid exchange intervals I believe in a rule of thumb I call the three C’s: 

Corporation - Follow the vehicle manufacturer's service tables. Every manufacturer provides service intervals for each fluid on the vehicle. The first service is easy since it is mileage or time-based. The subsequent services can be more difficult if you do not have the history of the vehicle to know when the first service took place. That’s where the next two C’s come into play.

Contamination - Any contamination of any fluid warrants a fluid exchange (possibly more depending on the severity and type of contamination). When inspecting fluid, look for things such as dirt, debris or incorrect fluid.

Color - Most fluids should still look and “smell” new when they are in good condition. I understand that discolored fluid does not in all cases equate to the fluid being bad, however, in most cases it is a good indicator. Use this “test” when service records are not available or when it is obvious the fluid is no longer providing adequate protection. 

Power steering - New technology

For several years now we have all seen fewer and fewer vehicles coming into our bays that use hydraulic power steering systems. By 2013 about half of all new vehicles used electric power steering. Today, nearly every light-duty vehicle sold does. This means the once common power steering fluid exchange will be nearly non-existent in the typical auto shop over the next few years. 

While the power steering fluid maintenance may be going away, there are still some things you should be looking for. 

Mechanical inspections of electric power steering systems are still every bit as important as before. 

Search for TSB’s. Since the switch to electric power steering systems, I have seen a much higher number of steering system-related TSB’s than the previous hydraulic systems.

Code scan - your vehicle inspection process should include a full system code scan of all modules. This will now include electric power steering systems. When trouble codes are found, they should be brought to vehicle owners’ attention and addressed.

Coolant - New and better fluids - New and different materials

There is no doubt you have noticed the many different coolant types, colors and brands used by the different auto manufacturers. Because of the many different formulas, it is recommended that you use the coolant called for by the vehicle manufacturer OR verify the coolant you are using meets or exceeds all the specifications called for. Every reputable coolant manufacturer will provide you with a list of what coolants their product can be used in place of. If they do not specifically list the coolant called for, do not use that product in that vehicle.

 On older vehicles, coolant contamination or degradation was more visible. Engine blocks and cylinder heads were cast iron, water pumps and other components were steel. This caused rusting which led to discoloration of the coolant when the corrosion inhibitors were no longer providing sufficient protection. With modern engines utilizing aluminum engine blocks and heads and more components made of plastic, there is little or no opportunity for rust. This means coolant that is no longer providing sufficient protection can look new and clean long after it’s service life. This makes service intervals more important when recommending coolant exchange. Don’t forget to test the freezing and boiling points of the coolant with a hydrometer and the alkalinity of the coolant with test strips.

Engine oil - New and better fluids - New and different materials

This is likely the most debated service interval of any. With more manufacturers today recommending a 10k mile oil change, you and your shop will need to decide how you will be advising your customers. I could really go into the weeds on this topic and talk about things like long-term cost of ownership, ability to advertise low maintenance vehicles and a few other subjective theories or thoughts I have; but let’s just look at the facts.

There are three large factors when deciding how many miles a vehicle can go between oil changes:

Oil type and quality

Filter size and capacity

Engine design and operation

I think most everyone agrees that modern synthetic oils themselves are more than capable of providing adequate protection for 10k miles or more. So on factor 1 let’s say the oil used should be a quality oil that meets or exceeds the specifications and recommended additive package standards published by the vehicle manufacturer.

Factor 2, the oil filter size and capacity. The more conventional canister type oil filters (Image 1) generally have smaller filter media than the now more commonly used cartridge type filters. The canister-type filters will go into bypass operation at around 7,500 miles (depending on several factors). This means the filter media has reached it’s holding capacity, which causes oil pressure to lift the bypass valve allowing oil to flow without filtration. Obviously, this is not an ideal scenario however, it is much more ideal than no oil flow. The cartridge-style filters are themselves the filter media and are almost always larger than the canister-type filters. This is allowing manufacturers to extend the typically 7,500-mile oil filter life to 10k miles. Either way, I think most can agree 10k is pushing the filtering capacity limits of any filter.

The third factor is engine or vehicle operation. 

Most manufacturers list all service recommendations under one of two categories: 

Standard (may use different terminology) and Severe (again may use different terminology). Your customers driving habits and climate conditions dictate which category their mileage recommendation falls under. 

Severe driving conditions include:

Stop and go driving

Regularly short drives (under 5 miles)

Consistent idling

Towing or hauling

Dusty environments

Consistently high or low ambient temperatures

A study by AAA found that only 6 percent of drivers polled said they felt like they drove mostly in severe conditions. But when asked about their actual driving behaviors, 62 percent said that their driving behaviors align with severe driving conditions all or most of the time.

Let’s look at one last factor before wrapping up the 10k oil change topic. I believe one of the most important benefits of an “oil change” or “oil service” is a vehicle inspection. Many drivers would not and do not bring their vehicle in for an inspection excluding their oil service visit. Things like oil leaks, road damage and failing components will now be unnoticed for a longer time. Think about brake service recommendations. Most shops recommend brake pad replacement at about 3 or 4/32”. Using some rough guesses or averages, brake pads wear roughly 1/32” every 4-5,000 miles. So a vehicle following the 10k mile oil change can use 2-3/32” between services. Hopefully you see the importance of a thorough brake inspection at every service. Mistaking a brake pad thickness for 4/32” when it is actually at 3/32” could result in a customer being told their brakes are good, yet they may not even make it to the next service to be inspected again.

So when to recommend oil service? Well, I think you and your shop will need to consider all these factors and educate your customers accordingly. I believe most customers can understand they fall under severe service conditions, which is likely a 7,500-mile recommendation. Either way, I believe it is important to suggest they return between services for an inspection.

Transmission Fluid - New and better fluids - New Technology

It seems like for years we had relatively few transmission fluid types being used. Then came along CVT transmissions, 10-speed transmissions, dual-clutch and several other transmission types. It now feels like every manufacturer has a new fluid every time you look. This topic could be its own article so I just want to keep it simple and bring attention to two important changing factors:

It is more important than ever on modern vehicles to verify the correct fluid type before performing a service. Never assume a fluid is compatible without verifying first.

Many techs prefer dropping the trans pan to change fluid and filter while others prefer to use fluid exchange equipment to exchange a larger percentage of the fluid. With changing transmission designs, you may have to compromise. Many transmissions no longer have a filter and or a serviceable fluid pan. Others do not have a method for attaching (at least easily) fluid exchange equipment. Consider a third less common method in these circumstances. When the preferred methods are not possible or ideal, I like to perform a drain and refill of the fluid. I then start the vehicle and shift through the gears a few times. Once the fluid is warm, I perform another drain and refill. A drain and refill is usually a fairly quick service, particularly when a drain plug is present. When performed twice, a large majority of the total fluid capacity is exchanged.

What about hybrid and electric vehicles - New technology

One of the fastest-changing maintenance sectors is the move to hybrid or electric vehicles in place of internal combustion engines. It’s no surprise to most that electric vehicles require less maintenance but it certainly isn’t none. These new technologies are also presenting different maintenance needs than what we have been used to. 

Cooling systems

(Figures 2 and or 2A) Did you know most hybrid vehicles have 2 cooling systems (ICE and power electronics) and most electric vehicles have 3 cooling systems (Power electronics, HV battery and HVAC)? Each of these systems has its own water pump and coolant cap. While the average ICE vehicle has somewhere around 10 coolant hoses, the average electric vehicle has over 20. Most of these hoses utilize plastic connections. This will certainly result in more cooling system repairs and maintenance than ICE vehicles. Here’s what you need to know to service these systems:

(Figure 3, on page 37) Coolant must be the correct type and meet all manufacturer specs including the use of deionized water (Not just distilled) when specified. When deionized water is specified, use premixed coolant from the manufacturer. Be aware, there are different standards or grades of deionized water, making it difficult to use the correct product for mixing with bulk coolant. Do yourself and your customer a favor and use a premixed coolant that meets all the manufacturer's specifications. Correct coolant must be used for all the same reasons as any other vehicle, with the addition of avoiding loss of isolation faults and corrosion of small electronic components such as heatsinks.

(Figure 5) Bleeding air from these cooling systems can be different. Be sure to read and follow the manufacturers’ process outlined in the service information. It is good practice to use a vacuum assist coolant refilling tool anytime a majority of the coolant has been removed. (Image 7) Most systems utilize electric water pumps and will require the use of a scan tool to run the water pump, which will move coolant in the system and help free trapped air.


Since both hybrid and electric vehicles use regenerative braking, they use the hydraulic braking system less. Combine this with the lightweight of the average hybrid / electric vehicle and you find the brake pads will generally last a long time. That doesn’t mean there is no maintenance to be done on these brake systems though. There are a few maintenance items you may not be aware of on these vehicles such as:

Slide pins are not “exercised” as often as those on a typical ICE vehicle; they tend to seize or become difficult to slide before the brakes would otherwise need service. 

(Figures 4 and 4A) Prevent this leading to premature brake pad wear by inspecting during normal vehicle inspection or service. To do this, use a small pry bar or flat head screwdriver to slowly and gently press against the brake pad pushing the caliper piston back just a small amount (~¼”), now grip the caliper and move it back and forth feeling for any restriction of the slide pins. If you feel restricted or they do not move, you should recommend a brake service to your customer. If the other brake components are in good condition I recommend removing all components to clean and lubricate as needed without parts replacement.

While the brake fluid is no different than that in a typical ICE vehicle, it seems to be overlooked more frequently. Be sure to recommend brake fluid service when recommended by the vehicle manufacturer (typically 24 months). You should also be inspecting for any contamination such as dirt, copper, and moisture.

When servicing hybrid and electric vehicle brake systems there is a lot of misinformation out there causing fear for some. Be sure to read service information before performing any brake system repairs and you will be just fine. To be clear, you should be reading service information prior to any brake system service as these systems are different from what you may be used to. 

Air conditioning

Be sure to verify the proper oil for any A/C system you are servicing. Hybrid vehicles have used several A/C compressor designs requiring different oil types and specs. Also, be sure to only use A/C dye that is specifically designed for use in hybrid / electric vehicles. Use of incorrect oils and dye can result in compressor failure and or loss of isolation faults.

12-volt battery 

When the battery fails on a typical ICE vehicle it is usually fairly obvious, the engine will crank over slowly or not at all. Most hybrid vehicles use the motor/generator to crank the engine over; some hybrids use a second battery. Electric vehicles do not have an ICE to crank over at all. This means the onset of battery failure is less obvious. Since the 12-volt battery is required to power on all the vehicle’s systems including the HV system, it is still a very important component. The vehicle may not power up, and on a plug-in vehicle, it may cause the HV battery not to charge when plugged in. So be sure to test the 12-volt battery anytime you service a hybrid or electric vehicle.

Hopefully, this article helps you to better educate your customer on their vehicle service needs. There have been many other changes to how we maintain modern vehicles not listed here. I only wanted to cover topics I believe have changed from what we are used to, and require a different method or process than what we have been using. Who knows what the future of automotive maintenance has in store for us. I believe it will include more software updates and calibrations as maintenance vs repairs, but we will see. I have no doubt that those of us who continue to learn and follow new trends will have no problem keeping up with these future changes.

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