Essential Automotive Fluids and How to Check Them

Power steering fluid tank photoMost DIYers know that ignoring fluid levels and fluid-change intervals virtually guarantees that a mechanical breakdown and shortened vehicle life are in your car’s not-too-distant future. Engine oil and coolant are probably the two fluids most vehicle owners think of, hear about, and check most frequently. However, there are several other fluids just as vital to a vehicle’s operation and longevity that many drivers inadvertently overlook. Here, we take you through those lesser-known fluids and how to check them.

Transfer Case Fluid

Vehicles with four-wheel or all-wheel drive have a transfer case on the back of the transmission. Its job is to direct power to the vehicle axles. Because it’s filled with rotating gears that are doing some heavy lifting and need constant lubrication, it needs to contain the right amount, type, and quality of transfer case fluid. Just like your vehicle’s other vital fluids, transfer case fluid degrades over time and needs to be changed. As a general rule of thumb, transfer case fluid should be changed every 30,000 miles, but it really depends on your manufacturer’s recommended guidelines and driving conditions.

Using a ’04 F150 with a 5.4 liter Triton V-8 and four-wheel drive as an example, Ford recommends changing the transfer case fluid at 150,000 miles. Shorter change intervals are recommended if the vehicle is driven through water, such as during stream crossings or when launching or retrieving a boat. That’s because there’s a chance water could seep into the transfer case and degrade the fluid’s lubricating properties sooner.

How to check transfer case fluid

Consult your manual to locate the transfer case on your vehicle. Unscrew the filler plug or cap. Use your finger or a dipstick to check the fluid level. If the fluid is low or if its dirty brown in color, you need to change it out.

Differential Fluid

Because wheels on the same axle don’t always turn at the same speed, every axle needs a differential. On front wheel-drive vehicles, the differential may be housed within the transmission and utilize the transmission fluid. On rear-wheel drive vehicles there’s a differential in the back, and on four-wheel drive vehicles there can be three differentials–one in the front, center and rear.

And, just like the transfer case fluid, differential fluids have to keep all those turning gears and parts lubricated and moving freely. Fortunately it too is usually a high-mileage interval change, but consult and follow specific vehicle-manufacturer recommendations to be sure.

How to check differential fluid

Locate the differential in your vehicle using the owner’s manual. Open the fill/service port and using your finger, check for fluid. If your finger touches fluid, then your fluid level is adequate. If the fluid doesn’t reach the service port opening, then your fluid is low and needs to be serviced.

Washer Fluid

Washer fluid is one of those fluids that you don’t know is low or empty until you need it and it’s not there. It’s also an important safety item, particularly in cold-weather climates where road slush and salt can quickly coat the windshield, instantly obscuring a driver’s vision. Washer fluid doesn’t need to be changed, mainly because it’s used and replaced frequently, but in cold-weather climates it’s important to ensure that the fluid won’t freeze. Most commercially available washer fluids are pre-mixed and won’t freeze so long as you don’t add water to them.

How to check windshield washer fluid

In most vehicles, washer fluid is blue and housed in a white plastic tank. Look on the side of the tank to see if the fluid level falls between the recommended levels, or open the cap covering the tank to check the fluid level.

Source | Flickr 

Brake Fluid

Brake fluid is hygroscopic, which means it attracts moisture. And moisture in brake fluid is a very destructive contaminant—it will corrode brake parts and eventually lead to system failure. The change interval, based on time and/or mileage, and specific type of brake fluid—there’s DOT 3, DOT 4, 5 and even 5.1—is important. Like most vehicle fluids which brake fluid you use depends on vehicle manufacturer specifications found online or in the owner’s manual.

How to check brake fluid

The reason the under-hood, brake-fluid reservoir on most vehicles is usually see-through is so that it can be checked at a glance, without removing the cap and introducing atmospheric moisture into the fluid. There will be “minimum” and “maximum” levels indicated. The fluid level should be in between. If the brake fluid looks dark brown and dirty it needs to be changed as well.

Power Steering Fluid

Power steering used to be an expensive add-on option for older vehicles, but today, nearly every vehicle comes equipped with it as a standard feature, making it much easier to turn the steering wheel without feeling as though you’re doing an upper-body workout. The system depends on a power steering pump and power steering fluid, and if you’ve ever turned the wheel and heard a loud groaning or moaning sound under the hood, chances are the power steering fluid was low. How often or even whether power steering fluid ever needs to be changed is vehicle-specific. Fluid levels always need to be maintained at the proper level, however, to prevent damage to the power steering pump, which could create hazardous driving conditions and require a much more expensive repair.

How to check power steering fluid

If you can’t find the power steering fluid reservoir, consult the owner’s manual for its location. It’ll either be an opaque tank where you can see the fluid level through the tank’s side, or the tank will have a removable cap and dipstick, possibly with a “hot” or “cold” marking indicating where the fluid level should be based on the engine temperature. Add the right amount, and the right type of power steering fluid.

Brake Fluid tank photo

Automatic Transmission Fluid

Automatic transmission fluid (ATF) lubricates and protects the transmission’s complex gears and also contains detergents that trap potentially destructive contaminants, holding onto them until they’re removed during a transmission fluid change. For the transmission to work properly, the right type of transmission fluid has to be used (there are many, and they are highly dependent on vehicle manufacturer specifications) and it has to be maintained at the proper level. Your car will tell you the ATF needs changing when you notice it is missing gears, its fuel economy is getting worse, or it revs up inconsistently.

How to check automatic transmission fluid

Consult your vehicle owner’s manual to locate the transmission fluid dipstick and for instructions on how to check the fluid level. Based on manufacturer, there could be differences in whether the fluid level should be checked when the vehicle is hot or cold, while it’s in park or neutral, and while it’s running or turned off.

The recommended transmission fluid change interval varies from vehicle to vehicle, and can also depend on whether synthetic or conventional ATF is being used. Consult your vehicle owner’s manual for the proper change interval—it could be as often as every 30,000 miles or as infrequently as every 100,000 miles. And while you’re at it, determine whether the maintenance schedule calls for changing the transmission fluid filter at the same time. A sure indication that the transmission fluid needs to be changed is if it’s dark or smells burned.

Fluids Can’t Be Ignored

Fluids are a vehicle’s lifeblood, and your vehicle is an expensive asset. Fluid maintenance is one of the easiest and most important ways you can protect it and help ensure miles and years of trouble-free driving.

Did we miss any important fluids? Do you have questions about any of the fluids we listed? Let us know in the comments.

Prep your car for summer

Advance Auto PartsEveryone knows you’ve got to get your car ready for snow season, but don’t forget about summer, folks. Your car could always use a little love, and summer presents some unique automotive challenges and opportunities. If you want to maximize your fun in the sun, check out my tips for making this car summer the best one yet.

1. Check Your Air Conditioning System

The thing about air conditioning systems is they have a way of quitting at the worst possible time. You might be stuck in traffic on a 90-degree day, for example, or in the middle of a scorching summer road trip through the Midwest. Sounds nasty, right? That’s why I recommend taking preemptive action and getting your air conditioning system checked before the summer months really heat up. Just head over to your trusted mechanic and have him run some diagnostic tests; it won’t cost you very much, and if anything needs fixing, you’ll be glad you didn’t find out the hard way.

2. Bring Out that Summer Shine

Washing your car in the winter months can seem pointless, because you’re just going to get it dirty again the next time you drive somewhere. But now that summer’s finally here, it’s worth putting in some quality time with your car’s paint and wheels. That means you’re going to want some car wash supplies, and I’m going to show you the absolute easiest way to achieve car detailing nirvana: just grab a bottle of Meguiar’s Ultimate Wash and Wax Anywhere. You don’t even need water! Just spray this stuff on your paint, grab a microfiber cloth, and wipe till dry. Don’t tell anyone, but I use it for my wheels, too. It only takes a few minutes to do the whole car, and you’ll be amazed at the results.

3. Check Your Washer Fluid

Most people are surprised by this one, but if you think about it, it makes sense. Winter brings inclement weather to most parts of the country, and that means folks have to squirt their windshields a lot more than usual. Result? Washer fluid reservoirs are often nearly dry by spring. Fortunately, that reservoir is usually right at the front of the engine bay, and it’s super-easy to open and refill yourself. Try this washer fluid from Rain X—I swear by it myself.

4. Focus on Inner Beauty

Last but not least, let’s not forget about the interior of your car. Like everything else, the cabin’s probably a little worse for wear thanks to winter stress. But that’s nothing a good scrub can’t fix. To remove all that winter dirt and grime from your dashboard and other hard-to-clean areas, try something like these interior detail brushes from Autocraft. And to get your upholstery looking fresh again, check out Turtlewax’s upholstery cleaner—it even leaves a protective coating when you use it.

5. Lubricate your Brakes

Another consequence of harsh winter driving is that your brakes have to work harder than usual. That means they could use some lubrication to get back up to snuff, so I recommend grabbing a bottle of Permatex’s Ultra Disc Brake Caliper Lube. It’s a cheap and incredibly effective product. If you’re not comfortable putting it on yourself, just bring it to your mechanic and ask him to give you a hand.

6. Enjoy the Drive!

Follow these tips and I promise you, you’ll be ready for anything summer’s got in store. Drive safe, friends, and have fun out there.


Editor’s note: As you plan to hit the road this summer, get trusted tips on how to maximize your mileage.

Checking Your Vehicle’s Essential Fluids and Hoses Provides Peace of Mind

hood up fixing car

Benjamin Franklin once said, “An ounce of prevention is worth a pound of cure.” The same is true for your vehicle, especially when it comes to its essential fluids and hoses. Regular maintenance checks of these items will contribute to the sustained health of your vehicle and reduce your risk of unpleasant automotive surprises down the road. But where to start? Here are a few things to keep in mind.

Essential fluids

High operating temperatures for your car, particularly during seasonal travel, mean more use of your air conditioner and an even stronger need to keep your engine well lubricated with enough coolant and oil. All fluid checks should be done while your engine is cold. This is VERY important because hot fluids can burn you.

All fluid checks should be done while your engine is cold. This is VERY important
because hot fluids can burn you.

  • Coolant: To check your coolant, unscrew the radiator cap and make sure the level is where it should be according to the line on the tank. If you’re low, topping off with a pre-mixed 50/50 coolant will save you time and fuss.
  • Motor oil: To check your oil, pull out the dipstick, wipe it down with a rag, and stick it back in. When you pull it out again, the oil should be at or above the line marked on the stick. If it’s too low, add a quart. Your owner’s manual will tell you what kind you need.
  • Windshield washer fluid: While you’re at it, check your windshield washer fluid. Your car may be able to survive without it, but a clear view of the road can be a life saver—literally. In most vehicles, washer fluid is blue and housed in a white plastic tank. Look on the side of the tank or open the cap covering the tank to check the fluid level.

For more helpful tips on checking essential fluids, read this.

Radiator hoses and spare tires

Fluids aren’t the only things that keep your vehicle running smoothly. Include these items in your regular inspections.

  • Radiator hoses: If coolant is the life blood of your engine, then radiator hoses are the arteries. So, while you’re under your hood, check your radiator hoses for leaks or wear. Squeeze the hoses and make sure they’ve got some give to them. If they’re hard and brittle or cracked, they should be replaced. It’s an easy job and far preferable to breaking down on the side of the road when you’re headed out to the lake with the family.
  • Spare tires: As long as you’re taking stock of your vehicle’s essentials, you may as well check your spare tire. First, make sure you have a spare tire in your car. Many vehicle manufacturers these days are eliminating spare tires as a standard feature. If you have a spare tire, make sure it’s properly inflated. Don’t forget to keep a tire iron in your trunk, along with any other equipment needed to change a tire by the side of the road. You can read through your owner’s manual to get a feel for what it takes to do the job. If you don’t have a spare tire on your vehicle, consider carrying a tire repair kit.

Many vehicle manufacturers these days are eliminating spare tires as a standard feature.

Checking the fluids and hoses on your vehicle will save you money and hassle. They’ll also give you something you can’t put a price on: peace of mind. Are there easy hose and fluid checks you perform on your vehicle? Leave us a comment.