2002-2008 Infiniti G35 Brake Fluid Type and Flush Interval

By Core Brake Parts Tech Team — Circleville, OH warehouse

Every 2002-2008 Infiniti G35 owner's document we checked calls for Genuine NISSAN Super Heavy Duty Brake Fluid or an equivalent DOT 3 fluid. Infiniti's published maintenance schedules for the G35 list brake fluid as an inspect item at every service, not as a timed replacement, so the right flush interval is driven by the fluid's condition: test it at each visit and flush when it shows moisture or depleted corrosion inhibitors, and any time the brake hydraulics are opened for repair.

What Brake Fluid the G35 Uses

The 2007 G35 Sedan Owner's Guide is explicit in two places. In the maintenance chapter it tells owners to add Genuine NISSAN Super Heavy Duty Brake Fluid or equivalent DOT 3 fluid up to the MAX line, and the Capacities and Recommended Fuel/Lubricants table lists the same specification for brake fluid. The same guide specifies that fluid for the clutch hydraulic reservoir on manual-transmission cars, so a six-speed G35 has two reservoirs under the hood that take the same DOT 3 grade.

The guide also carries a warning worth taking seriously: use only new fluid, because old, inferior or contaminated fluid may damage the brake system, and improper fluids can affect the car's stopping ability. It also cautions that brake fluid damages paint, and to wash any spill off with water immediately.

DOT 3, DOT 4, DOT 5.1 and DOT 5: What Is Safe in a G35

The DOT grades are set by federal standard FMVSS No. 116, and the difference that matters is boiling point. The standard requires a minimum dry boiling point of 401 F for DOT 3, 446 F for DOT 4 and 500 F for DOT 5. The wet minimums, measured after the fluid has absorbed a set amount of moisture, are 284 F for DOT 3, 311 F for DOT 4 and 356 F for DOT 5. Those wet numbers show why old fluid is the real problem: moisture pulls the boiling point down, and boiled fluid turns into vapor that compresses under pedal pressure.

• DOT 3 is what Infiniti specifies and is the correct choice for a stock street G35.
• DOT 4 and DOT 5.1 are glycol-based like DOT 3. Brake & Front End's fluid FAQ states that all DOT 3, 4 and 5.1 fluids are compatible with each other and with all systems, and ADVICS notes the three are technically compatible while still advising against mixing grades. If you track the car or drive a Brembo-equipped model hard, a full flush to a quality DOT 4 raises the boiling margin. Flush completely rather than topping off one grade with another.
• DOT 5 is silicone-based. Never put it in a G35. ADVICS warns never to mix silicone and glycol-based fluids, and Brake & Front End describes the two lumping together in the system. In an ABS-equipped car that is a hydraulic unit you do not want to clean out.

ADVICS also points out a trade-off: DOT 3 absorbs less water from the air over time than DOT 4, which means it can go longer between changes. Moving to DOT 4 for heat capacity means committing to checking it more often.

How Often to Flush G35 Brake Fluid

Infiniti's 2005 Service and Maintenance Guide, which covers the G35, lays out three schedules. Schedule 1, for repeated short trips, stop-and-go traffic in hot weather, dusty or salt-spread roads, or towing, runs every 3,750 miles or 3 months. Schedule 2, for mostly highway driving in temperate conditions, runs every 7,500 miles or 6 months. Premium Maintenance uses the 3,750-mile interval with more items checked. In the maintenance log, which runs to 120,000 miles or 96 months, brake fluid appears as "Brake fluid level" under Inspect, and there is no line to replace it. Infiniti's current online maintenance tool for the 2004, 2006 and 2008 G35 shows the same inspect-only pattern and says brake fluid should be replaced as specified to prevent unnecessary wear from contamination.

That is not the same as saying the fluid lasts forever. Infiniti's own explanation is that moisture in brake fluid lowers its effectiveness and can cause corrosion. On a car that is now close to two decades old or more, the practical rule is:

• Test the fluid at every oil service with a moisture or copper test strip. Brake & Front End explains that rising copper content means the anti-corrosion additives are depleted and corrosion may be happening inside the system.
• Flush when the test fails, when the fluid has turned dark, or when you have no record of the last flush. On a used G35 with unknown history, flush it now.
• Flush whenever you replace a caliper, hose, line or master cylinder, since fresh fluid has to be bled through those parts anyway.
• Flush before any track day or hard mountain driving, and after a session where the pedal went soft from heat.

Signs the Fluid Is Overdue

• Soft or sinking pedal after hard stops that firms up once the brakes cool. This is the classic symptom of fluid boiling in the calipers.
• Dark brown or black fluid in the reservoir. Fresh DOT 3 is clear to light amber.
• Brake warning light on with the parking brake released. The owner's guide says this light warns of low fluid. Low fluid usually means worn pads (the caliper pistons have moved out and taken fluid with them) or a leak. Check pad thickness before simply topping off.
• Fluid added frequently. The guide says the system should be checked if fluid must be added often. A dropping reservoir with good pads points to a leak at a caliper, hose, line or master cylinder.
• Brake and ABS lights together. The guide notes this may indicate the ABS is not functioning properly; have the system checked before driving on.

Flushing a G35: What to Expect

A brake fluid flush on a G35 is a moderate DIY job with two people, or a one-person job with a pressure or vacuum bleeder. The basic process:

1. Use only new DOT 3 (or a full change to DOT 4) from a sealed container. The federally required label on every bottle says to keep the container clean and tightly closed to prevent absorption of moisture.
2. Remove as much old fluid from the reservoir as you can and refill with new fluid.
3. Bleed each corner in the order the factory service manual specifies, until clean fluid with no bubbles comes out, keeping the reservoir above MIN the whole time. Running it dry lets air into the ABS unit, which may then need a scan-tool bleed.
4. Tighten the bleeder screws to the value in the factory service manual; they are small and easy to strip or snap.
5. On manual cars, bleed the clutch hydraulics as well, since they use the same fluid grade and it ages the same way.
6. Set the level to MAX, road test at low speed, and confirm a firm, high pedal.

What to Replace at the Same Time

A flush is the ideal moment to handle anything that would require opening the hydraulics again. If the pads are low, fit new ones first so the caliper pistons are pushed back and the reservoir level reads true afterward. For Brembo-equipped G35s we carry street pads such as the Hawk Ceramic Street front pads HB545Z.564 for G35 with Brembo and the Hawk HPS front pads HB545F.564, plus the EBC Yellowstuff front pads for 2003-2004 G35 manual with Brembo for owners who drive hard. Rotors that are scored or below minimum thickness should go at the same time; see the EBC USR slotted front rotor set for 2002-2004 G35 automatic or browse all brake rotors.

Also inspect the rubber flex hoses at each wheel. Infiniti's maintenance guide says to check brake lines for chafing, cracks, deterioration and signs of leaking and to replace damaged parts immediately. Aged hoses can swell under pressure and add pedal travel no flush will cure; replacements are in our brake hoses and brake lines collections.

Frequently Asked Questions

What brake fluid does an Infiniti G35 take?

Genuine NISSAN Super Heavy Duty Brake Fluid or an equivalent DOT 3 fluid, per the G35 owner's guide. The same fluid goes in the clutch reservoir on manual-transmission cars.

Can I use DOT 4 in my G35?

Yes. DOT 4 is glycol-based and compatible with DOT 3 systems, and it has higher minimum boiling points under FMVSS 116. Do a complete flush rather than mixing, and check it more often, since DOT 4 absorbs moisture faster than DOT 3.

Can I use DOT 5 in a G35?

No. DOT 5 is silicone-based and should never be mixed with the glycol fluid the G35 was built with.

Does Infiniti have a set brake fluid change interval for the G35?

Infiniti's G35 maintenance schedules list brake fluid level as an inspect item at every 3,750- or 7,500-mile service, with no timed replacement. Replace it based on condition testing, discoloration, unknown history, or whenever the hydraulics are opened.

Why is my G35 brake warning light on?

With the parking brake released, the light indicates low brake fluid. Check pad wear first, since worn pads lower the reservoir level. If the pads are good and the level keeps dropping, find the leak before driving further.

Do Brembo-equipped G35s need a different brake fluid?

The owner's guide lists one brake fluid specification for the car. Brembo-equipped cars that see track or hard canyon use benefit from fresher fluid and a possible full change to a quality DOT 4.

Sources

1. 2007 Infiniti G35 Sedan Owner's Guide - DOT 3 / Genuine NISSAN Super Heavy Duty specification, clutch fluid spec, use-new-fluid and paint warnings, brake warning light behavior
2. 2005 Infiniti Service and Maintenance Guide (NHTSA file copy) - Schedule 1, Schedule 2 and Premium intervals, brake fluid level inspect-only in the maintenance log, brake line inspection guidance
3. Infiniti USA: 2006 G35 brake fluid maintenance schedule - inspect intervals, moisture and corrosion explanation
4. 49 CFR 571.116, FMVSS No. 116 Motor vehicle brake fluids - dry and wet boiling point minimums, container labeling on moisture
5. ADVICS: Breaking Down the DOT Ratings for Brake Fluid - glycol chemistry, DOT 3 vs DOT 4 moisture absorption, never mix silicone and glycol
6. Brake & Front End: Brake Fluid DOT 3, 4, 5 and 5.1 FAQ - DOT 3/4/5.1 compatibility, DOT 5 incompatibility, copper testing