2008-2015 Infiniti G37 Brake Fluid Type and Flush Interval

By Core Brake Parts Tech Team — Circleville, OH warehouse

The Infiniti G37 uses Genuine NISSAN Super Heavy Duty Brake Fluid or an equivalent DOT 3 fluid. That is what the owner's manual specifies for both the brake system and, on manual-transmission cars, the clutch hydraulics. Infiniti's published maintenance schedule calls for replacing the brake fluid every 30,000 miles or 24 months under standard driving, and every 15,000 miles or 12 months under severe or premium driving conditions.

Below is what that spec means, why the interval matters on a car that gets driven the way many G37 owners drive them, and how to do the flush right.

What Brake Fluid the G37 Takes

The capacities table in the G37 owner's manual lists brake and clutch fluid as Genuine NISSAN Super Heavy Duty Brake Fluid or equivalent DOT 3. The maintenance section repeats it: if the level is below the MIN line or the brake warning light comes on, add that fluid up to the MAX line. The same fluid feeds the clutch master on six-speed manual cars, which share the reservoir area under the hood.

The Nissan-branded DOT 3 is sold under part number 999MP-A4100P, and it is the same fluid dealers use when servicing Nissan and Infiniti vehicles. You do not have to use the branded bottle. Any fluid that is labeled DOT 3 is certified to the federal standard, FMVSS No. 116, which sets minimum boiling points and other performance requirements.

Intervals above are from Infiniti's online schedule for the 2011 and 2013 G37. Schedules can vary slightly by model year, so enter your exact year on Infiniti's maintenance schedule site to confirm.

Why Brake Fluid Wears Out

Brake fluid does not get used up, but it does degrade. Glycol-based fluids such as DOT 3 absorb moisture from the air over time, through the reservoir cap vent and through rubber hoses and seals. Infiniti's own maintenance page explains that contaminated, wet fluid reduces braking efficiency and can cause corrosion inside the system.

The federal numbers show why. FMVSS 116 requires fresh DOT 3 to have a dry boiling point of at least 401 degrees F. Once the fluid is humidified to roughly 3.7 percent water, the standard only requires a wet boiling point of 284 degrees F. That drop is the whole reason for the replacement interval. When fluid in the calipers boils during hard or repeated stops, it forms vapor bubbles, and vapor compresses. The pedal goes soft or sinks toward the floor right when you need the brakes most.

Moisture also attacks metal. Caliper bores, pistons and the ABS hydraulic unit are all exposed to whatever is in the fluid, and corrosion there is far more expensive to fix than a fluid flush.

Standard vs Severe Schedule: Which One Applies to You

Infiniti splits the G37 schedule into standard and severe driving. Under severe or premium conditions, the brake fluid interval is cut in half, to 15,000 miles or 12 months. The G37 is a 3.7-liter V6 sport sedan and coupe, and plenty of owners drive them hard: mountain roads, autocross, track days, frequent spirited driving, or heavy stop-and-go in hot weather. All of that heats the brakes and pushes fluid closer to its boiling point.

A practical way to decide:

• Mostly highway commuting, gentle stops: the standard 30,000 miles or 24 months is appropriate.
• City traffic in a hot climate, short trips, humid region: lean toward the severe schedule.
• Performance pads, spirited canyon driving, autocross or track days: use the severe schedule at minimum, and flush before any track event.

Whichever you pick, the time limit matters as much as the miles. A G37 that only sees weekend use still absorbs moisture, so a low-mileage car can need fluid based on the calendar.

Signs the Fluid Needs Attention

The owner's manual tells you to keep the level between the MAX and MIN lines and to check it whenever you check oil or refuel. Watch for these:

• Brake warning light on with the parking brake released. On the G37 this light doubles as the low brake fluid warning. The manual says to stop, check the level, add fluid if needed and have the system checked. If the level is below MIN, it says not to drive until the brakes have been inspected.
• Level dropping over time. Some drop is normal as pads wear, because the caliper pistons move out and hold more fluid. A sudden drop, or needing to top up often, points to a leak.
• Soft or spongy pedal, or a pedal that sinks. Can mean air, boiled fluid or a leak. The manual says to see a technician immediately.
• Dark, cloudy fluid. Fresh DOT 3 is clear to amber. Dark fluid is old and contaminated.
• Fade after repeated hard stops. A pedal that gets longer during a hard drive is a classic sign of fluid near its boiling point.

Remember that if the level is low because the pads are worn, topping it off to MAX will cause the reservoir to overflow when you push the pistons back for new pads. Check pad thickness before you add fluid.

How to Flush G37 Brake Fluid

A full flush replaces all the fluid in the lines, calipers and ABS unit, not just the reservoir. A simple bleed with a helper works on the G37, as does a pressure or vacuum bleeder.

1. Buy enough fresh fluid in sealed bottles. The manual warns to use only new fluid from a sealed container. Federal labeling rules require every bottle to say to keep it tightly closed to prevent moisture absorption, so do not use a half-empty bottle that has been open on a shelf.
2. Protect the paint. The manual cautions that brake fluid damages paint. Cover the fender and rinse any spill with water right away.
3. Clean the reservoir cap before opening it, as the manual instructs, so dirt does not fall into the system.
4. Remove old fluid from the reservoir with a clean syringe and refill with fresh fluid.
5. Bleed each caliper starting with the wheel farthest from the master cylinder and working closer, unless the factory service manual for your car specifies a different sequence. Keep going at each bleeder until the fluid runs clean and bubble-free.
6. Never let the reservoir run dry during bleeding, or you will pull air into the master cylinder and possibly the ABS unit.
7. Bleed the clutch on manual-transmission cars, since it uses the same fluid.
8. Tighten bleeder screws to the value in the factory service manual, top the reservoir to MAX, and confirm a firm pedal before driving.

Difficulty: a moderate DIY job with basic tools and a helper. If you get a soft pedal that will not firm up after bleeding, air may be trapped in the ABS unit, which may need a scan tool procedure at a shop.

DOT 3 vs DOT 4, and What to Replace at the Same Time

Infiniti specifies DOT 3. DOT 4 fluids have higher minimum boiling points under FMVSS 116, which is why some performance drivers choose them. If you go that route, choose a glycol-based fluid labeled DOT 4, do a complete flush rather than mixing, and keep to the severe-service interval. Do not use silicone DOT 5 fluid in a system designed for glycol DOT 3. When in doubt, stick with what the owner's manual calls for.

A pad job is the natural time to flush, since you already have the wheels off and the pistons are being pushed back. We carry pads that fit the G37:

• EBC Bluestuff NDX front brake pad set for the 2008-2015 G37 3.7
• EBC Bluestuff NDX rear brake pads for the 2008-2015 G37 3.7
• Hawk Performance HPS front pads for the 2009-2012 G37 Sport

If the pedal feels soft even after a flush, inspect the rubber hoses at each corner. You can browse replacement brake hoses and stainless brake lines, or see all brake parts.

Frequently Asked Questions

What type of brake fluid does an Infiniti G37 use?

Genuine NISSAN Super Heavy Duty Brake Fluid or an equivalent DOT 3 fluid, per the owner's manual. The same fluid is used for the clutch on manual-transmission models.

How often should I change the brake fluid on my G37?

Infiniti's schedule lists every 30,000 miles or 24 months for standard driving, and every 15,000 miles or 12 months for severe or premium driving. Use whichever limit you hit first.

Can I use DOT 4 in my G37?

Infiniti specifies DOT 3. A glycol-based DOT 4 has higher minimum boiling points under the federal standard, and some performance drivers use it. If you switch, do a full flush and keep the shorter interval. Never use silicone DOT 5.

Why is my brake warning light on?

On the G37 the brake warning light also warns of low brake fluid. If it comes on with the parking brake released, check the level. If it is below MIN, the manual says not to drive until the system is checked, because low fluid usually means worn pads or a leak.

Is it OK to just top off the reservoir instead of flushing?

Topping off restores the level but does nothing about moisture already in the fluid. The fluid in the calipers, where heat is highest, is the oldest and wettest. Only a full flush replaces it.

Does the G37 clutch need its fluid changed too?

Manual-transmission G37s use the same brake fluid for the clutch hydraulics, so bleed the clutch when you flush the brakes to keep the pedal feel consistent.

Sources

1. 2012 Infiniti G37 Sedan Owner's Manual - fluid spec (Nissan Super Heavy Duty or DOT 3), clutch fluid, MAX/MIN, low fluid warning light, sealed container and paint warnings
2. Infiniti USA: 2011 G37 brake fluid maintenance schedule - 30,000 miles/24 months standard, 15,000 miles/12 months severe and premium
3. Infiniti USA: 2013 G37 brake fluid maintenance schedule - same intervals confirmed for 2013
4. 49 CFR 571.116, FMVSS No. 116 Motor Vehicle Brake Fluids - DOT 3/4/5 dry and wet boiling point minimums, 3.7 percent water humidification, container labeling
5. Nissan Race Shop: OEM Nissan DOT 3 Brake Fluid - part number 999MP-A4100P, dealer-service fluid