2004 Acura NSX Complete Maintenance Schedule & Service Guide

The 2004 Acura NSX represents the final years of the first-generation NSX, powered by the legendary 3.2L V6 (C32B) engine producing 290 horsepower. As a hand-built exotic, its maintenance requirements are critical—particularly the timing belt, as the C32B is an interference engine where belt failure causes catastrophic and expensive engine damage.

> CRITICAL ENGINE NOTE: The C-series V6 uses a timing belt, not a chain. This is an interference engine. If the belt breaks while driving, the pistons will strike the valves. Replacement is mandatory, not optional .

Key Takeaways

• The NSX uses a timing belt (NOT a chain) on an interference engine. Replacement is required at 105,000 miles or 7 years , whichever comes first. If driven in extreme temperatures (under -20°F or over 110°F), replace every 60,000 miles .
• For a 2004 NSX, age is the critical factor. With the 7-year interval, the belt should have been replaced in 2011, 2018, and again in 2025. If the timing belt service history is unknown, replace it immediately regardless of mileage.
• Service at an Acura dealer is NOT mandatory to keep warranties in effect. Maintenance may be done by any qualified service facility or skilled person . Keep all receipts as proof of completion.
• For major periodic service, this should generally be done every 2 years or after 30,000 kilometers (approximately 18,600 miles) .
• The NSX uses specific fluids: 5W-30 engine oil, Honda MTF for the manual transmission, Honda ATF-DW1 for the automatic, and Honda Type 2 blue coolant. Do not substitute.

Engine & Drivetrain Specifications

The 2004 Acura NSX is the final iteration of Honda's hand-built supercar.

Engine Architecture: The C32B features titanium connecting rods, forged pistons, and a dual-stage intake manifold. It is hand-assembled by Honda's most experienced technicians, and replacement engines are exceptionally rare and expensive. This makes proper maintenance critical.

Timing Belt Specifications:

• Compatible belt: Dayco 95231
• Manufacturer-rated interval: 105,000 miles
• Water pump driven by timing belt — replace simultaneously

Owner's Maintenance Checks

The following checks must be performed regardless of mileage :

Understanding Maintenance Codes

The 2004 NSX predates Honda/Acura's modern Maintenance Minder system. However, general Acura maintenance codes apply as a reference:

Service at Independent Shops – Important

From the 2004 NSX Owner's Manual :

> *"Service at a dealer is not mandatory to keep your warranties in effect. Maintenance may be done by any qualified service facility or skilled person."*

However, Acura recommends that all maintenance services be performed at the recommended time or mileage period to ensure long-term reliability . According to state and federal regulations, failure to perform maintenance on items marked with # will not void your emissions warranties .

Keep all receipts as proof of completion, and have the person who does the work fill out the Maintenance Record .

Timing Belt – The Most Critical Service

The C32B engine requires timing belt replacement on a strict schedule. This is the single most important maintenance item for the 2004 NSX.

Factory Replacement Intervals

NSX Prime Community Confirmation

From the NSX Prime forum, the leading NSX enthusiast community :

> *"For the '97 and later NSX, the recommendation in the service manual and owner's manual is to change it after 105K miles or 7 years, whichever comes first."*

Why the Timing Belt Is Critical

The Dayco timing belt product page explains :

> *"When the timing belt breaks, the synchronization of the engine parts is lost. When this happens, on most engines the valves interfere with the pistons. As a result, valves can be broken with possibly even more severe and expensive damage to pistons, cylinders, etc."*

For the NSX's interference engine, a broken timing belt will cause the pistons to strike the open valves, resulting in bent valves, damaged pistons, and typically requiring complete engine replacement.

Replacement costs vs. engine replacement:

• Timing belt service: $2,000-$3,000 at a specialist
• New C32B engine from Acura: $20,000+
• Used C32B engine: $10,000+

The Age Factor – Critical for 2004 NSX Owners

For a 2004 NSX in 2025, the age factor is paramount. The 7-year interval means:

If the timing belt history is unknown, assume it is original and replace it immediately. One NSX Prime member noted :

> *"While you are well under the miles constraint, you are living on borrowed time with respect to how old your NSX is. Your call, but a t-belt job is a lot less expensive than replacing bent valves."*

Timing Belt Replacement – The "Full Job"

When replacing the timing belt, NSX specialists recommend refreshing the engine while it's apart :

As noted in the NSX Prime discussion :

> *"When you change the timing belt, it's a good time to change all the cooling system hoses. The seven-year interval is appropriately long, and doing it with the timing belt serves as a reminder to do so."*

> *"If you are considering any other services within the next year or two - valve adjustment, brake fluid flush, transmission fluid flush, etc - you may as well have those done at the same time. Some will save labor cost due to better access to the engine when things are apart."*

Engine Oil Change Guidance

Factory Recommendations

How to Check Oil Level

1. Park on level ground and wait at least 3 minutes after engine shutdown
2. Pull out the dipstick and wipe completely clean
3. Reinsert fully, then remove again
4. Oil level should be between the upper and lower marks

Owner Guidance

• Acura Genuine Motor Oil is recommended, though any quality synthetic of the same viscosity is acceptable
• The C32B is a high-performance engine that may consume oil under hard driving—monitor levels regularly
• For tracked NSXs, many owners use a slightly thicker viscosity for better protection at high temperatures

Transmission Service

6-Speed Manual Transmission

Owner Guidance: The NSX 6-speed manual is legendary for its precision. Use only Honda MTF for optimal shift feel. The clutch fluid shares the brake fluid reservoir and must be checked monthly .

4-Speed Automatic Transmission

Spark Plug Replacement

Valve clearance should be inspected and adjusted at the same time .

Engine Coolant Service

Owner Guidance: Do not use generic green coolant. Honda Type 2 coolant is specifically formulated for aluminum engine components. The NSX's mid-engine layout makes the cooling system critical—maintain it meticulously.

When replacing the timing belt and water pump, the coolant will be flushed as part of the service .

Brake & Clutch Fluid Replacement

Owner Guidance: A complete system flush is required—topping off the reservoir is not sufficient. The NSX's braking system is critical for safety. Check the level monthly and keep between MIN and MAX marks .

Drive Belt & Air Filters

Owner Guidance: The NSX's engine air filter is accessible from the engine bay. A clogged filter reduces performance—replace it annually or more frequently in dusty conditions. The serpentine drive belt is replaced during timing belt service as it must be removed to access the timing belt .

Valve Clearance Inspection

Owner Guidance: The C32B uses mechanical lifters (not hydraulic). Valve clearances should be checked every major service. Tight exhaust valves can lead to burned valves—this is especially important on a high-revving engine like the NSX .

Severe Driving Conditions

The following conditions shorten maintenance intervals :

Major Periodic Service

For major periodic service, this should generally be done every 2 years or after 30,000 kilometers (approximately 18,600 miles) .

Scheduled Maintenance Summary

The table below shows recommended reference intervals for the 2004 NSX:

NSX-Specific Long-Term Ownership Considerations

Find a Qualified NSX Specialist

The NSX is a low-volume exotic with unique engineering. Most factory-trained dealer techs have retired. NSX owners recommend finding a specialist shop with NSX experience rather than taking it to a general Acura dealer .

Age Affects More Than Just the Timing Belt

For a 2004 NSX in 2025 (21 years old):

NSX Prime Community Wisdom

From the NSX Prime forum :

> *"Read The Owner's Manual. There are two variables that are to be taken into consideration when changing rubber hoses, belts, seals, etc. 1 - miles, 2 - years."*

> *"The 7-year interval is appropriately long, and doing [hoses] with the timing belt serves as a reminder to do so. And there are parts and labor savings in doing the water pump and hoses at the same time (since the coolant is flushed only once)."*