2013-2019 Mazda CX-5 Brake Fluid Type and Flush Interval

By Core Brake Parts Tech Team — Circleville, OH warehouse

Every 2013-2019 Mazda CX-5 sold in the U.S. calls for brake fluid that meets SAE J1703 or FMVSS 116 DOT 3, according to Mazda's own owner's manuals. Mazda's U.S. maintenance schedules for these years list brake fluid level inspections rather than a fixed replacement mileage, but Mazda's schedules for other markets call for replacing the fluid every 24 months, and yearly under hard use or in very humid climates. For most owners, a flush every two years is the sound, factory-backed rule of thumb.

What brake fluid the 2013-2019 CX-5 uses

Mazda's lubricant tables are consistent across both generations of the CX-5 covered here. The 2016 U.S. owner's manual lists "Brake/Clutch fluid" as SAE J1703 or FMVSS116 DOT-3, and the 2017 and 2019 manuals list the same DOT-3 specification. That covers the first-generation model (2013-2016) and the redesigned second generation (2017-2019).

DOT 3 is a glycol-ether fluid. It is defined by a federal standard, FMVSS 116, which sets minimum boiling points for each grade. The numbers below are from that standard:

The "wet" figure is the one that matters as a CX-5 ages. It is the boiling point after the fluid has absorbed moisture, and it is a lot lower than the fresh-from-the-bottle number. That drop is the entire reason brake fluid gets changed on a calendar, not on the odometer.

Can you use DOT 4 in a CX-5?

Yes. DOT 3, DOT 4 and DOT 5.1 are all glycol-based, and brake industry references describe them as compatible with each other and with glycol systems. DOT 4 meets a higher boiling-point minimum than DOT 3, so it is an acceptable choice if that is what you have. What you must never add is DOT 5. It is silicone-based, it does not mix with glycol fluid, and it does not belong in a CX-5's ABS and stability-control hydraulics. If you are unsure, use exactly what the cap and the manual say: DOT 3.

How often to flush brake fluid on a 2013-2019 CX-5

This is where the paperwork gets confusing, so here is exactly what Mazda publishes.

• U.S. schedules (2016 and 2019 manuals): Schedule 1 lists brake lines, hoses and connections and disc brakes for periodic inspection. Schedule 2 (severe driving) adds a "Brake and clutch fluid level" inspection at every service. Neither U.S. table has a brake fluid "Replace" row.
• Mazda schedules for other markets: the international CX-5 owner's manual lists brake fluid replacement at 24, 48, 72 and 96 months for most regions, and Mazda's Mexico schedules in the U.S.-published manuals also include a brake fluid replace row.
• Severe use: the international manual states that if the brakes are used extensively, such as continuous hard driving or mountain driving, or the vehicle is operated in extremely humid climates, the brake fluid should be replaced annually.

The hardware is the same fluid in the same kind of system, so the absence of a U.S. line item does not mean the fluid lasts forever. Glycol fluid keeps absorbing moisture through hoses, seals and the reservoir vent. The federal labeling rule for brake fluid containers even requires the warning to keep the container tightly closed to prevent absorption of moisture. Our practical recommendation for a 2013-2019 CX-5: flush every two years, every year if you tow, drive mountain grades, or live somewhere humid, and any time the fluid looks dark.

Signs your CX-5's brake fluid needs attention

• Fluid level near MIN: Mazda's manual says the level normally drops as pads wear, because the caliper pistons move outward and hold more fluid. A level that is excessively low, though, can mean worn linings or a leak, and Mazda warns that a low level is dangerous and the brakes should be inspected.
• Dark, cloudy or dirty fluid: fresh DOT 3 is clear to light amber. Brown or murky fluid is contaminated and overdue.
• Soft or sinking pedal: air or moisture in the system, a leak, or a master cylinder bypassing internally.
• Pedal fade on long downhill runs: old, wet fluid can boil at the caliper, which feels like the pedal going long when the brakes are hot.
• Brake warning light: if the red brake warning light stays on with the parking brake released, check the fluid level first. Do not keep topping it off without finding why it dropped.

Test strips that react to fluid condition are a quick at-home check, but a two-year flush is inexpensive insurance even when the fluid looks fine.

Where the reservoir is and how to check it

The brake fluid reservoir is the translucent plastic tank on top of the master cylinder, shown in the engine compartment overview of your owner's manual. Mazda's manual says to keep the level between the MAX and MIN lines and to inspect it regularly. On manual-transmission CX-5s, the brakes and clutch draw fluid from the same reservoir, which is why Mazda calls it brake/clutch fluid.

1. Park on level ground with the engine off.
2. Wipe the cap and the area around it clean before opening, so dirt cannot fall in.
3. Read the level against the MAX and MIN marks on the translucent reservoir.
4. If you add fluid, use a fresh, sealed bottle of DOT 3 (or DOT 4) and do not overfill past MAX.
5. Cap it tightly right away. Opened bottles absorb moisture from the air, so do not store a half-used bottle for years.

How the flush is done, and what to replace at the same time

A proper flush pushes old fluid out of every caliper, not just the reservoir. The usual order is to start at the wheel farthest from the master cylinder and work toward the closest one, keeping the reservoir from running dry so air does not get into the ABS unit. A pressure bleeder or a two-person pedal bleed both work. Tighten bleeder screws to the value in the factory service manual; they are small and easy to strip.

A flush is a natural time to look at everything the fluid touches:

• Pads and rotors: the CX-5 uses disc brakes, and Mazda's schedules list disc brake inspection at each service. If the pads are thin, do them with the flush. We carry fitment-specific parts such as the 2013-2019 Mazda CX-5 front ceramic brake pads, plus a full range of brake rotors and ceramic brake pads.
• Hoses: check the flexible rubber lines at each wheel for cracks, bulges or seepage. Replacement brake hoses are cheap compared with a hose failure.
• Calipers and bleeders: a seized bleeder or a sticking slide pin shows up during a flush. If a caliper leaks at the piston seal, replace it with a reman unit from our brake calipers collection.
• Hardware: new clips and slide-pin boots from a brake hardware kit keep new pads from dragging.

How hard is the job?

Checking and topping off is a two-minute driveway task. A full flush is a moderate DIY job: you need a way to lift the CX-5 or remove the wheels, a clear catch hose and bottle, one or two bottles of fresh fluid, and patience to bleed every corner until clean fluid comes out with no bubbles. If the pedal feels soft afterward, or an ABS warning appears, have the system bled with a scan tool that can cycle the ABS pump.

Frequently Asked Questions

What type of brake fluid does a 2013-2019 Mazda CX-5 take?

Mazda specifies fluid meeting SAE J1703 or FMVSS 116 DOT 3 in the U.S. owner's manuals for these years. DOT 4 is also compatible because both are glycol-based.

Is brake fluid replacement in the U.S. CX-5 maintenance schedule?

The 2016 and 2019 U.S. schedules list fluid level and brake line inspections, not a fixed replacement interval. Mazda's schedules for other markets call for replacement every 24 months, and that is a sensible interval for U.S. vehicles too.

Can I mix DOT 3 and DOT 4 in my CX-5?

Yes, they are compatible glycol fluids. Mixing lowers the boiling point to somewhere between the two, so for best results flush fully to one fluid. Never add DOT 5 silicone fluid.

Why is my CX-5 brake fluid level going down?

A slow drop is normal as the pads wear, since the caliper pistons extend and hold more fluid. A sudden or large drop points to a leak or very worn pads and needs an inspection before you drive.

Should I flush the brake fluid when I replace my pads?

It is a good time to do it if the fluid is due or discolored. Pushing pistons back to fit new pads also moves old, contaminated fluid back toward the ABS unit, so many techs prefer to open the bleeder and flush at the same time.

Sources

1. Mazda USA - 2016 CX-5 Owner's Manual, Lubricant Quality - Brake/Clutch fluid SAE J1703 or FMVSS116 DOT-3
2. Mazda USA - 2017 CX-5 Owner's Manual, Lubricant Quality - brake fluid DOT-3 on the second generation
3. Mazda USA - 2019 CX-5 Owner's Manual, Lubricant Quality - brake/clutch fluid DOT-3 for 2019
4. Mazda USA - 2016 CX-5 Owner's Manual, Brake/Clutch Fluid - MAX/MIN level, shared reservoir, low-level warning
5. Mazda USA - 2016 CX-5 Scheduled Maintenance, Schedule 2 - U.S. brake and clutch fluid level inspections
6. Mazda USA - 2019 CX-5 Scheduled Maintenance - U.S. schedules list inspection; Mexico schedules list brake fluid replacement
7. Mazda CX-5 Owner's Manual (international) - replace brake fluid every 24 months; annually for hard driving or humid climates
8. 49 CFR 571.116 (FMVSS 116) - Motor vehicle brake fluids - DOT 3/4/5 dry and wet boiling-point minimums, moisture labeling
9. Brake and Front End - Brake Fluid DOT 3, 4, 5 and 5.1 FAQ - glycol fluid compatibility; DOT 5 silicone does not mix