Why Oil Cooling Matters for the Nissan 370Z

The Nissan 370Z, equipped with the VQ37VHR engine, is a capable sports car that thrives under high-revving conditions. However, its factory oil cooling system is adequate for street driving but quickly becomes a weak point during prolonged high-load events such as track days, autocross, or spirited canyon runs. Engine oil serves as both a lubricant and a coolant; when oil temperatures climb beyond 250°F (121°C), viscosity breaks down, leading to increased friction, accelerated wear, and potential for thermal shock. Factory oil coolers on the 370Z are often small and located in a position that sees limited airflow, especially when the car is moving slowly or stationary. This is why aftermarket upgrades like the Mishimoto oil cooler have become a near-essential modification for owners who push their 370Z beyond daily driving.

High oil temperatures also trigger the engine control unit to pull timing and enrich the fuel mixture as a protective measure, resulting in power loss and reduced throttle response. By maintaining oil temperatures in the optimal 200–230°F range, the engine can operate at peak efficiency without electronic intervention. This is particularly important for the VQ37VHR, which is known for its high specific output and sensitivity to heat. A well-designed oil cooler system not only extends service intervals but also protects critical components such as bearings, piston rings, and the variable valve timing mechanism.

The Mishimoto Advantage

Mishimoto has built a reputation for engineering cooling solutions that balance performance, durability, and ease of installation. Their oil cooler kit for the Nissan 370Z is no exception. Designed as a direct-fit system, it eliminates the guesswork often associated with universal coolers and custom hose routing.

Bar-and-Plate Core Construction

Mishimoto uses a bar-and-plate core design rather than the less efficient tube-and-fin style found in many factory coolers. Bar-and-plate cores offer superior heat transfer because the oil passes through a series of flat tubes with internal turbulators, while air flows through the gaps between the plates. This design maximizes surface area and promotes turbulent airflow, which pulls heat away from the oil more effectively. The core is also brazed in a controlled atmosphere furnace, ensuring leak-free joints and resistance to vibration fatigue—a critical factor in a car that sees track use.

Black Series Thermostatic Sandwhich Plate

The kit includes Mishimoto’s Black Series thermostatic sandwhich plate, which mounts between the factory oil filter and the engine block. This plate contains a wax-element thermostat that opens at 195°F (91°C), allowing oil to bypass the cooler when cold for faster warm-ups. Once the oil reaches operating temperature, the thermostat diverts flow through the cooler. This is a major advantage over non-thermostatic setups: it prevents over-cooling during winter or short commutes, which can actually increase engine wear by keeping oil too thick to flow properly. The thermostatic plate also has ports for oil pressure and temperature senders, making it easy to integrate aftermarket gauges.

AN-10 Fittings and Braided Hoses

Mishimoto supplies AN-10 (dash-10) push-lock fittings and black nylon-braided hoses. AN-10 line size is the industry standard for oil coolers on mid- to high-horsepower V6 engines because it provides sufficient flow without excessive pressure drop. The push-lock system requires no special tooling—just push the hose onto the barb and secure with the included Oetiker clamps. This simplifies installation for DIYers while still offering a professional-grade hold that withstands high pressure and heat cycling. The braided hose is abrasion-resistant and can be routed cleanly around the engine bay without kinking.

Dual-Pass Cooler Mounted in the Front Bumper

The cooler itself measures roughly 20″ x 6″ x 2.5″ and uses a dual-pass internal design, meaning oil flows back and forth through the core before returning to the engine. This doubles the time the oil spends in contact with cooling surfaces without increasing the size of the cooler. It mounts directly to existing holes in the 370Z’s front bumper support using supplied bracketry—no drilling or cutting is required. The cooler sits behind the lower grille opening, where it receives direct airflow from the car’s motion and also benefits from the radiator fan’s draw when stationary.

Installation Overview

While the original article mentions easy installation, a step-by-step breakdown helps owners decide whether to tackle the job themselves or hire a shop. Most experienced DIYers can complete the install in 3–4 hours with basic hand tools and a jack.

Step 1: Preparation and Safety

Start by parking the car on level ground and allowing the engine to cool completely. Disconnect the battery negative terminal to avoid any electrical shorts. Drain the engine oil into a clean container if you plan to reuse it (recommended: change oil with the cooler install to ensure clean oil cycles through the new system). Remove the factory oil filter.

Step 2: Remove the Front Bumper Cover

The 370Z’s front bumper cover must be removed to access the mounting location for the cooler. This involves removing a series of push clips, screws, and two bolts behind the wheel well liners. Carefully pull the bumper cover forward, disconnect the fog light harnesses (if equipped), and set the cover aside. This step is straightforward but requires patience to avoid breaking clips.

Step 3: Install the Thermostatic Sandwhich Plate

Apply a thin layer of clean engine oil to the O-ring on the sandwhich plate. Screw the plate onto the engine block in place of the factory oil filter, torquing to 18–22 lb-ft. Mount the supplied adapter to the sandwhich plate so that the hose ports face the direction you want the lines to run (typically toward the driver’s side). Install the new oil filter onto the sandwhich plate itself—Mishimoto includes a filter with a bypass valve appropriate for the kit.

Step 4: Mount the Oil Cooler

Position the cooler in the lower grille area, aligning it with pre-existing holes in the metal bumper support. Use the supplied bracket, bolts, washers, and nylon lock nuts. Ensure the cooler sits level and the inlet/outlet ports are oriented downward to prevent air trapping. Tighten hardware to the spec provided in the manual.

Step 5: Route and Connect Hoses

Measure and cut the two hoses (supplied as a 10-foot section) to length. Attach push-lock fittings to each end: slip the hose onto the barb, then secure the Oetiker clamp using a clamp pliers. Route the hose from the “OUT” port on the sandwhich plate to the cooler’s inlet, and from the cooler’s outlet back to the “IN” port on the plate. Keep hoses away from hot exhaust manifolds, sharp edges, and moving belts. Use zip ties to secure the hoses along the chassis rail.

Step 6: Fill and Bleed

Reinstall the front bumper cover. Fill the engine with fresh oil (6.9 quarts for a standard 370Z, plus a small amount for the cooler and lines). Start the engine and let it idle for a few minutes, then check for leaks. Turn the steering lock-to-lock to bleed any air from the system. Verify oil level on the dipstick and top off as needed. Take the car for a short drive, then recheck for leaks and oil level after the engine cools.

Cost Breakdown

The original article lists $300–600 for the cooler and $100–200 labor. Here is a more granular look at real-world pricing as of 2025.

Mishimoto Oil Cooler Kit (Part Number: MMOOC-370Z)

The kit retails for $539.95 on Mishimoto’s website and typically sells for $450–530 through authorized dealers like Z1 Motorsports, Concept Z Performance, or Amazon. This includes the bar-and-plate cooler, thermostatic sandwhich plate, AN-10 push-lock fittings, hoses, Oetiker clamps, mounting brackets, hardware, and a new oil filter.

Additional Parts and Consumables

  • Engine oil (6–7 quarts of 5W-30): $30–50 depending on brand.
  • Oil filter (already included, but a spare may be desired): $10–20.
  • Optional: Oil temperature and pressure gauges: $150–400 for a dual-gauge setup with senders. Recommended for monitoring real-time temps.
  • RTV silicone or thread sealant: $5–10 if you need to seal any adapter fittings.

Labor Costs

Professional installation at a performance shop (e.g., shops specializing in Nissan/Infiniti) ranges $200–350. Dealerships may charge $400+ but are less experienced with aftermarket coolers. DIY installation saves labor but requires tools: jack, jack stands, socket set, push-lock clamp pliers ($20), and trim removal tools ($10).

Total estimated cost for DIY installation: $495–$600 (kit + oil + tools).
Total estimated cost with professional install: $650–$950.

Expected Performance Gains

Real-world data from 370Z owners on forums like The370Z.com show consistent temperature drops after installing the Mishimoto kit:

  • Street driving (ambient 80°F): Oil temps stabilize at 200–210°F, compared to 220–235°F with the factory cooler.
  • Spirited back-road driving: Temperatures peak at 220–230°F rather than 250–260°F, staying well below the threshold where timing retard occurs.
  • Track session (20-minute lapping): Oil temps barely exceed 230°F, versus 270°F+ without an aftermarket cooler. This allows sustained high-rpm operation without pulling power.

Dyno tests on tuned 370Zs have shown a gain of 5–8 horsepower and 6–10 lb-ft of torque after installing a thermostatic oil cooler, primarily because the engine no longer reduces timing due to heat. However, the biggest gains are in consistency: lap times remain stable for full sessions rather than dropping off after three laps as oil heats up.

Impact on Daily Driving

Even for street users, the cooler provides faster warm-up (thanks to the thermostatic bypass) and lower oil temps in stop-and-go traffic when the cooling fan cycles. Many owners report the oil temperature needle stays at the vertical position (12 o’clock) even in summer heat, whereas factory cars often see the needle climb past the 3/4 mark.

Long-Term Benefits for Engine Health

Consistent oil temperature control directly extends engine life. The VQ37VHR is prone to gallery gasket failures and timing chain tensioner issues when subjected to repeated thermal cycles above 250°F. By keeping peak temps below 240°F, the oil cooler reduces oxidation rates, maintains film strength on bearings, and prevents varnish buildup in the PCV system. Owners who install the cooler typically report lower oil consumption and cleaner oil analysis reports over 30,000-mile intervals.

Additionally, the cooler protects the transmission and differential indirectly—lower engine bay heat reduces the thermal load on nearby components. It is a common recommendation on 370Z forums to install an oil cooler before any horsepower modifications (intake, exhaust, tune) to ensure reliability gains compound.

Alternatives and Comparison

While the Mishimoto kit is a top choice, other options exist. Stewering away from blind brand loyalty, consider these:

Setrab / Earl’s Custom Coolers

Setrab cores are used in top-tier motorsports and offer even higher thermal capacity than Mishimoto’s bar-and-plate. A custom kit using a Setrab core, Earl’s AN-10 fittings, and a Setrab thermostatic plate can run $600–800. These allow more flexibility in mounting location and cooler size, but require fabrication skills. They are overkill for a mostly-street 370Z.

CSF Radiator and Oil Cooler Combo

CSF offers a combined radiator and oil cooler replacement for the 370Z that fits in the factory location. Cost is around $700–900. This setup simplifies the installation (no external cooler mounts) but does not deliver as large a temperature drop as a dedicated front-mount oil cooler. It is suitable for light track use but not heavy lapping.

Factory-Plus Upgrade Options

Z1 Motorsports sells a high-efficiency factory-style oil cooler plate that replaces the OEM unit for about $150. This improves cooling modestly (10–15°F) and is a budget option for owners who cannot do a full system. However, for any performance driving, the Mishimoto kit remains the price-to-performance champion.

Maintenance and Considerations

Once the cooler is installed, oil capacity increases by approximately 0.5–0.7 quarts. Always check oil level with the engine warm and running. The cooler core can collect debris; inspect the front grille area every oil change and clean with a soft brush or compressed air. The thermostatic plate’s O-ring should be replaced if leaking. Regularly inspect hose routing for abrasion or chafing—use spiral wrap or silicone tape on areas that contact the chassis.

If you live in a very cold climate, note that the thermostatic plate prevents over-cooling, but the large cooler sits in airflow and can still cool oil below thermostat setpoint in extreme sub-zero driving. In such conditions, covering part of the cooler with a grille block for winter may be needed.

External Resources

Conclusion

Installing a Mishimoto oil cooler on a Nissan 370Z is not just a performance mod—it is a reliability necessity for anyone who drives the car hard. The initial investment of $500–$900 pays for itself through reduced engine wear, consistent power delivery, and the confidence to enjoy the car without worrying about oil temps. With a straightforward DIY installation, robust bar-and-plate construction, and a thermostatic bypass that preserves street manners, the Mishimoto kit offers an ideal balance of cost and capability. Whether you plan to track your 370Z weekly or just enjoy aggressive back-road drives, this upgrade provides measurable results that protect your engine and enhance your driving experience.