2013-2017 Acura ILX Brake Fluid Type and Flush Interval

By Core Brake Parts Tech Team — Circleville, OH warehouse

The 2013-2017 Acura ILX is specified for DOT 3 brake fluid - the owner's manual calls for Acura (earlier manuals say Honda) Heavy Duty Brake Fluid DOT 3. Acura's maintenance schedule says to replace the brake fluid every 3 years, independent of what the Maintenance Minder shows on the dash. Never put DOT 5 in an ILX; the manual warns it can cause extensive damage to the brake system.

What Brake Fluid the Acura ILX Uses

Every ILX from the 2013 launch through 2017 - the 2.0L, the 2.4L, and the 1.5L Hybrid - uses a conventional glycol-based DOT 3 hydraulic brake system. The owner's manual lists the fluid by name rather than just by DOT rating: Acura Heavy Duty Brake Fluid DOT 3 in the later manuals, and Honda Heavy Duty Brake Fluid DOT 3 in the earlier printing. It is the same factory fluid sold under both badges.

The manual also covers what to do if you cannot get the factory fluid. You can use DOT 3 or DOT 4 fluid from a sealed container as a temporary replacement, but Acura warns that using any non-Acura brake fluid can cause corrosion and decrease the longevity of the system, and it recommends having the system flushed and refilled with the specified DOT 3 as soon as possible afterward. The sealed-container part matters: an opened bottle that has been sitting on a garage shelf has already been pulling moisture out of the air.

Why DOT 3, and Why Never DOT 5

DOT ratings come from Federal Motor Vehicle Safety Standard No. 116, which sets minimum performance for brake fluid. A fluid sold as DOT 3 must meet an industry minimum dry boiling point of 401 degrees F; DOT 4 must meet 446 degrees F. Both DOT 3 and DOT 4 are glycol-ether based, which is why a sealed DOT 4 is acceptable as a stopgap in an ILX.

DOT 5 is different chemistry - it is silicone-based and does not mix with glycol fluids. Acura's own wording is blunt: brake fluid marked DOT 5 is not compatible with the ILX braking system and can cause extensive damage. If someone has topped your reservoir off with DOT 5, do not keep driving on it and do not just add more DOT 3. The system needs to be flushed completely and inspected.

Note that DOT 5.1 is a glycol fluid despite the name. It is still not what the ILX manual lists, so stay with the specified DOT 3 for routine service.

The 3-Year Flush Rule and the Maintenance Minder

The ILX uses Acura's Maintenance Minder, which reads oil life and pops up service codes with letter and number sub-items. The catch is that the Minder is mostly driven by engine operating conditions, and brake fluid does not wear out from miles - it wears out from time. So Acura adds a separate rule in the maintenance section: independent of the Maintenance Minder information, replace the brake fluid every 3 years.

In practice, that means a low-mileage ILX that rarely sees a Minder code still needs a brake fluid flush on a calendar schedule. If your car is a 2013-2017, most original-fluid cars are now years overdue unless there is a receipt showing the flush.

Why time matters: glycol brake fluid is hygroscopic, meaning it absorbs water from the air through hoses, seals and the reservoir cap vent. As water content rises, the boiling point falls. Under hard or repeated braking the caliper heats the fluid, and moisture-laden fluid can boil and form vapor bubbles. Vapor compresses where liquid does not, and the result is a soft or sinking pedal right when you need the most braking. Water in the fluid also promotes internal corrosion in the ABS unit, calipers and brake lines - which is exactly the longevity problem Acura's corrosion warning is about.

How to Check the ILX Brake Fluid Level

• Park on level ground with the engine off and open the hood.
• Find the translucent brake fluid reservoir on top of the master cylinder at the back of the engine bay.
• Read the level against the MIN and MAX marks on the side of the reservoir. The fluid should sit between them.
• Wipe the cap and surrounding area clean before opening it so dirt cannot fall in.

A low reading is a symptom, not just a top-off job. Acura's instruction is that if the fluid is at or below the MIN mark, you should have the system inspected for leaks or worn brake pads as soon as possible. As pads wear, the caliper pistons extend and hold more fluid, so the reservoir level drops slowly over the life of the pads. A level that drops quickly, or wet spots on the inside of a tire or around a caliper, points to a leak.

On manual-transmission 2.4L cars, you will also find a clutch fluid reservoir. It is checked the same way against its own MIN and MAX marks, and Acura says a clutch level at MIN calls for an inspection for leaks or an excessively worn clutch.

Doing the Flush: What It Involves

A proper flush is not a reservoir suction-and-refill. The old fluid has to be pushed out through each caliper bleeder until clean, fresh DOT 3 comes through, working from the wheel farthest from the master cylinder toward the closest, and never letting the reservoir run dry (which pulls air into the lines and possibly the ABS modulator). Check the factory service information for the ILX bleeding sequence and any model-specific steps, especially on the Hybrid.

For a DIYer with a helper or a one-person bleeder, it is a moderate job. The hardest parts are breaking loose seized bleeder screws without rounding them and keeping air out. If the pedal feels soft after bleeding, re-bleed before driving. Tighten bleeders snugly and to the value in the factory service manual - do not overtighten them into the caliper.

Use a fresh, sealed bottle of the specified DOT 3 and throw away anything left open for long. Brake fluid also strips paint, so rinse any drips off the body with water right away.

What to Replace at the Same Time

A brake fluid service is a good time to look at the rest of the system, because the wheels are already coming off:

• Pads: If you are near the end of the pad material, replacing them before the flush avoids pushing pistons back into fresh fluid later. We carry Hawk HPS 5.0 front pads for the 2013-2014 ILX Hybrid and EBC Yellowstuff front pads for the 2013-2015 ILX Hybrid, plus the wider brake pad collection.
• Rotors: Measure thickness and check for runout. Options include the Hawk Talon drilled and slotted front rotor set for the 2013 ILX Base and the EBC GD Sport slotted front rotors for the 2017 and newer ILX 2.4L, or browse all brake rotors.
• Hoses and bleeders: Cracked or swollen rubber hoses let moisture in faster and can balloon under pressure. See brake hoses and brake hardware kits.

Frequently Asked Questions

Can I use DOT 4 in my Acura ILX?

Only as a temporary measure. The manual allows DOT 3 or DOT 4 from a sealed container if the specified Acura DOT 3 is not available, then recommends flushing and refilling with the specified fluid as soon as possible.

How often should I flush the brake fluid on an ILX?

Every 3 years. Acura states this applies independent of the Maintenance Minder, so do it on the calendar even if you drive very little.

Will the Maintenance Minder tell me when the brake fluid is due?

Do not rely on it alone. Acura says to replace the brake fluid every 3 years independent of the Maintenance Minder, so track the date of the last flush yourself.

My ILX brake fluid is at the MIN line. Should I just add more?

Topping up to the proper level with the correct fluid is fine for getting home, but Acura says a level at or below MIN calls for an inspection for leaks or worn brake pads as soon as possible. Find the reason first.

What happens if DOT 5 was put in by mistake?

Acura warns DOT 5 is not compatible and can cause extensive damage. Stop adding fluid and have the entire system flushed and inspected.

Sources

1. Acura ILX Owner's Manual - Brake/Clutch Fluid - Heavy Duty Brake Fluid DOT 3 specification, DOT 5 warning, MIN/MAX level and inspection guidance
2. Acura ILX Owner's Manual - Maintenance Minder - replace brake fluid every 3 years independent of the Maintenance Minder
3. Acura Owners - ILX Maintenance Minder - Acura's 3-year brake fluid replacement statement
4. 2016 Acura ILX Owner's Manual - Brake Fluid - sealed DOT 3/DOT 4 temporary substitute and non-Acura fluid corrosion warning
5. Lucas Oil - Synthetic Brake Fluid DOT 3 and DOT 4 - FMVSS 116 minimum dry boiling points of 401 F (DOT 3) and 446 F (DOT 4)