2014-2019 Kia Soul Brake Fluid Type and Flush Interval

By Core Brake Parts Tech Team — Circleville, OH warehouse

The second-generation Kia Soul (2014-2019) takes glycol-based brake fluid meeting FMVSS 116 DOT 3 or DOT 4; Kia's owner's manual lists "FMVSS116 DOT-3 or DOT-4" in its recommended lubricants table. Kia's normal maintenance schedule calls for the brake fluid to be inspected at 60,000 miles or 48 months, and because all glycol fluid absorbs moisture over time, a full flush every 2 to 3 years is the practical interval most owners should plan around.

What brake fluid the 2014-2019 Kia Soul uses

The Soul's hydraulic brake system, including the master cylinder, the ABS/stability control modulator and the calipers, is designed for standard glycol-ether brake fluid. The owner's manual allows either of two federal grades:

• DOT 3 - the baseline glycol fluid most shops keep in bulk.
• DOT 4 - also glycol-based, with a higher minimum boiling point.

Both are defined by Federal Motor Vehicle Safety Standard 116, which sets minimum boiling points for new ("dry") fluid and for fluid that has absorbed water ("wet"):

DOT 5 is silicone-based and is not what Kia specifies, so do not put it in a Soul even though its boiling numbers look better on paper. The wet boiling point column is the one that matters as the fluid ages: it is the floor the standard allows once the fluid has picked up moisture.

If you are topping up and do not know what is already in the reservoir, DOT 4 is the safer pick because it meets the higher boiling requirement. Kia's manual also says to never mix different types of fluid, so if you want the whole system on DOT 4, the clean way to get there is a complete flush rather than a top-off. Always read the reservoir cap as well; it is the final word for your specific car.

How often to flush brake fluid on a Kia Soul

Here is where owners get confused. The normal maintenance schedule in the Soul owner's manual lists "Inspect brake fluid" at 60,000 miles or 48 months. It does not list a fixed replace interval on that page. Inspection means checking the level, the color and the condition, and replacing the fluid when it is due.

Brake fluid does not wear out by mileage. It degrades with time because it is hygroscopic: Brembo explains that the fluid absorbs moisture from the air through the porosity of the brake hoses, and that moisture turns to vapor under hard braking long before the fluid reaches the boiling point printed on the bottle. Vapor compresses, so the pedal goes long and soft. Brembo generally recommends replacing brake fluid every 2 to 3 years, while noting the carmaker's specification comes first.

A realistic plan for a 2014-2019 Soul:

• Every oil change or two: check the level in the reservoir between the MIN and MAX marks.
• Every 2 to 3 years: full flush with fresh DOT 3 or DOT 4 from a sealed container, regardless of mileage.
• At Kia's 60,000 mile / 48 month inspection: if it has not been flushed in the last few years, flush it now.
• Any time you replace a caliper, hose or master cylinder: bleed the system, and consider a full flush while you are in there.

Cars in humid climates, cars that sit for long stretches, and Souls that do a lot of mountain driving or loaded driving belong on the shorter end of that range.

Signs the fluid in your Soul is due

• Dark fluid in the reservoir. Fresh glycol fluid is clear to pale amber. Dark brown fluid is old and contaminated.
• Soft or sinking pedal, especially after repeated stops on a long downhill. That is the classic sign of moisture-laden fluid that has started to vaporize.
• Level dropping over time. A slow drop is normal as the pads wear, because the caliper pistons move outward and hold more fluid. Kia's manual notes that if the system needs frequent additions of fluid, it should be inspected. A fast drop means a leak at a caliper, hose, line or the master cylinder.
• Brake warning light on the dash with the parking brake fully released. On many cars this comes on when the reservoir level falls low. Find out why before just adding fluid.
• Unknown history. If you bought a used Soul and have no record of a flush, assume it is due.

Before you top up, look at the pads. Brembo's own guidance is to inspect the pads and rotors first, because a lowered fluid level often just reflects worn friction material. If you top the reservoir to MAX on worn pads, then install new pads, the pistons push the fluid back and it can overflow.

How to check and top up the reservoir

1. Park on level ground with the engine off.
2. Find the translucent reservoir on top of the master cylinder at the back of the engine bay on the driver's side, and read the level against the MIN and MAX marks on its side.
3. Wipe the cap and the area around it clean before opening it. Kia's manual specifically calls this out to keep dirt out of the system.
4. If needed, add DOT 3 or DOT 4 from a freshly opened, sealed bottle up to MAX. Do not overfill.
5. Reinstall the cap tightly and wipe up any drips. Brake fluid damages paint, and Kia warns to keep it away from your eyes; flush with plenty of clean water if it gets in them.

Buy small bottles. FMVSS 116 requires every container to carry the warning to keep the container tightly closed to prevent moisture absorption, which is why a half-used bottle that has sat open in the garage for a year is not fresh fluid anymore.

Doing the flush: difficulty and what to replace at the same time

A brake flush on a Soul is a moderate DIY job. The basic method is to remove most of the old fluid from the reservoir, refill with fresh fluid, then bleed each wheel until clean fluid comes out, never letting the reservoir run dry. A two-person pedal bleed or a pressure bleeder both work. Because the Soul has ABS and stability control, keeping air out of the hydraulic modulator matters; if air gets into the modulator, some procedures require a scan tool to cycle the ABS pump. If the pedal stays soft after bleeding, have a shop with the right tool finish it.

A flush is also the ideal time to deal with other brake work, since you will be bleeding the system anyway:

• Pads. If the fronts are getting thin, fitting new pads during the flush saves a second bleed. Our 2014-2019 Kia Soul front ceramic brake pads by Bosch are one option, and you can browse all ceramic brake pads.
• Rotors. Warped or scored rotors should be replaced along with pads; see our brake rotors.
• Hoses. Cracked or swollen rubber hoses let moisture in and can cause a soft pedal. Replace them from our brake hoses collection.
• Calipers. A caliper that leaks at the piston seal or sticks should be replaced; old wet fluid is one reason internal corrosion develops. See brake calipers.
• Hardware. Fresh clips and pins from our brake hardware kits keep new pads sliding freely.

Tighten bleeder screws and caliper bolts to the values in the factory service manual, and pump the pedal to a firm feel before moving the car.

Frequently Asked Questions

Can I use DOT 4 in my 2014-2019 Kia Soul?

Yes. The owner's manual lists FMVSS 116 DOT 3 or DOT 4. DOT 4 has a higher minimum boiling point, so it is a good choice. To avoid mixing types, switch over with a full flush rather than topping up.

Can I use DOT 5 brake fluid in a Kia Soul?

No. DOT 5 is silicone-based and is not a fluid Kia specifies for the Soul. Stick with glycol-based DOT 3 or DOT 4.

Does Kia say how often to change brake fluid on the Soul?

The normal maintenance schedule calls for inspecting the brake fluid at 60,000 miles or 48 months. Brake makers such as Brembo recommend replacing it every 2 to 3 years because the fluid absorbs moisture with age, not with miles.

Why is the brake fluid level in my Soul going down?

A slow drop usually just means the pads are wearing and the caliper pistons have moved out. A quick drop, a wet wheel, or a soft pedal points to a leak that needs to be found before driving.

Is DOT 3 fluid bad for my Soul?

No. DOT 3 is approved in the owner's manual. It simply has lower minimum boiling points than DOT 4, which matters most for heavy braking and old fluid.

Sources

1. Kia Soul 2016 Owner's Manual - Recommended lubricants and capacities - brake fluid spec FMVSS116 DOT-3 or DOT-4
2. Kia Soul 2016 Owner's Manual - Normal maintenance schedule - inspect brake fluid at 60,000 miles or 48 months
3. Kia Soul 2016 Owner's Manual - Brake fluid - MIN/MAX check, clean cap, never mix fluid types, frequent additions warning
4. 49 CFR 571.116 (FMVSS 116) Motor vehicle brake fluids - DOT 3/4/5 dry and wet boiling points, container moisture warning
5. Brembo - Brake fluid for your car - moisture absorption through hoses, 2 to 3 year replacement, follow carmaker spec
6. Brembo Parts - Brake fluid: when changing it - vapor forms below labeled boiling point, check pads before topping up