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If your Infiniti G37 is showing transmission overheating or leaking, replacing the cooler line can restore proper cooling and prevent damage. Choosing the right Infiniti G37 transmission cooler line matters because fitment, material quality, and connection type determine long-term reliability and ease of installation. This guide covers the top shortlisted options for the G37 and explains the key factors we evaluated, such as line material, corrosion resistance, and how straightforward each option is to install. Read on to understand the differences between hard lines and hose assemblies, common symptoms of a failing cooler line, and the features to prioritize when selecting a replacement for your vehicle.
Looking for other parts? See all Infiniti G37 parts & accessories.
Top Picks at a Glance
| Best Reviewed A top-rated pick with lots of positive feedback | A-Premium Automatic Transmission Oil Cooler Line Hose Assembly |  |
| Most Popular A crowd favorite that many people choose with confidence | Generic 52" Stainless Steel Braided Transmission Cooler Line Kit (AN6) |  |
| Best Quality Built to a higher standard if you want something more solid | Dorman 624-097 Transmission Oil Cooler Line (crimped OE FIX) |  |
| Best Budget The cheapest option that still gets the job done reliably | Byredio AN6 Braided Fuel/Transmission Hose 20 ft |  |
| Most Sold A high-volume bestseller chosen again and again | Generic 70" Stainless Steel Braided AN6 Transmission Cooler Line Kit |  |
| Best Value for Money The sweet spot between price and what you get | MuHize Stainless Steel Braided Transmission Cooler Line Kit, 70-inch |  |
| Best Overall The best all-around choice for most situations | EVIL ENERGY 6AN Braided Transmission Cooler Line Kit, 15 ft |  |
1. A-Premium Automatic Transmission Oil Cooler Line Hose Assembly
| Manufacturer Part Number | APOCL187 |
|---|---|
| OEM Part Number | 5005204AA, 5005204AC, 5005204AD, 5005204AE, 5005204AF, 5005204AG, 5005205AA, 52014764AA, 624-284 |
| Compatible Transmissions | 6 Speed Transmission |
| Vehicle Fitment Notes | Pressure and Return or Inlet and Outlet configurations for compatible 3.6L, 3.8L and 4.0L V6 models |
This oil cooler line assembly replaces the factory transmission cooler hose to restore a sealed fluid path between the transmission and external cooler. It is supplied pre-formed with fittings and is intended for in-vehicle replacement when the original line leaks or is damaged. Notable points include vehicle-specific reference numbers and multiple fitment options covering pressure and return or inlet and outlet configurations for compatible 3.6L, 3.8L and 4.0L V6 applications. Buyers can expect corrosion-resistant construction and a ready-to-install length that matches the factory routing, which simplifies swap-in repairs and reduces downtime. Several user reports indicate good fit and leak-free performance after installation, though some installers noted the small caps and caps color made distinguishing lines harder and that retaining clips may be needed separately. This is a practical, reliability-oriented replacement part for a vehicle needing a like-for-like cooler line swap, but it is not positioned as an upgraded high-performance braided line.
Best for: Reliability-focused buyers who prioritize a factory-style, drop-in replacement to fix leaks and restore proper transmission cooling without experimenting with aftermarket upgrades.
Less Ideal for: Drivers seeking a heavy-duty or braided upgrade for high-temperature or heavy-towing use should consider performance lines designed for those demands.
- Direct-fit assembly matched to factory routing for straightforward replacement
- Corrosion-resistant materials intended to provide leak-free service
- Includes vehicle reference numbers to help verify compatibility before ordering
- Pre-formed hose with fittings reduces installation time compared with fabricating a line
- Not marketed as an upgraded or heavy-duty line for high-performance or towing use
- Some customers reported included caps and fittings differ from factory appearance or fit
- Retaining clips are not consistently supplied and may need to be reused or purchased separately
Verdict A practical, factory-style cooler line replacement that restores leak-free operation for compatible V6 transmissions but is not a performance upgrade.
2. Generic 52" Stainless Steel Braided Transmission Cooler Line Kit (AN6)
| Material | Stainless Steel and PTFE |
|---|---|
| Length | 52 Inches |
| Fitting size | AN6 (6AN) |
| Compatible transmissions | Turbo 350/400/200/700R4/4L60/4L60E/4L65E/4L80E and Ford C4/C6/AOD (listed) |
This kit supplies stainless steel braided PTFE lines and AN6 fittings to create or repair transmission cooler plumbing on vehicles that use AN6-style connections. It is typically used to route fluid from a transmission to an auxiliary cooler or back to the radiator, and the 52-inch length covers many common routing paths. The stainless braid combined with a PTFE inner hose gives flexibility while resisting abrasion and corrosion, and the kit includes multiple 90-degree fittings and transmission inserts to simplify attachment. In practice the kit makes it easy to add cooling capacity for towing or heavy use, and reviews show the lines hold pressure and can be installed with basic hand tools. Quality appears inconsistent across batches so expect to check fittings and threads before installation and be ready to source a couple of additional adapters for exact fitment to factory connections. This is a practical, low-cost option when you need a universal AN6 plumbing solution, but buyers who require a vehicle-specific, drop-in hose may prefer a dedicated factory-replacement line.
Best for: Convenience-driven buyers who want a ready-made, low-effort way to add or replace transmission cooler plumbing for routine towing or aftermarket cooler installs.
Less Ideal for: Owners seeking a factory-quality, vehicle-specific replacement line or a fit-and-forget part should consider a model-specific hose or professional hose-building service instead.
- Stainless steel braid over PTFE core resists abrasion and corrosion.
- Includes AN6 fittings and several 90-degree adapters for common routing needs.
- 52-inch length suits many transmission-to-cooler runs without custom hose building.
- Flexible enough for DIY installation with basic hand tools.
- Multiple transmission inserts are provided for easier connection to common transmissions.
- Universal AN6 fittings may not match factory radiator or transmission ports requiring extra adapters.
- Quality control varies between batches so some buyers report damaged or improperly sized parts on arrival.
- Not a vehicle-specific, plug-and-play replacement for Infiniti G37 factory lines.
Verdict A convenient universal AN6 braided line kit that works for many cooler installs but may require adapters or quality checks for a perfect fit on an Infiniti G37.
3. Dorman 624-097 Transmission Oil Cooler Line (crimped OE FIX)
| Material | Metal, Rubber |
|---|---|
| Maximum Pressure | 100 Pound per Square Inch |
| Manufacturer Part Number | 624-097 |
| Position | Center |
This Dorman transmission oil cooler line replaces the original line with a crimped hose-to-metal connection intended to resist the common failure caused by rusted spring clamps. It is used where the factory line runs between the transmission and radiator to circulate and cool transmission fluid. The crimped fitting is marketed as about eight times stronger than the original clamp design, which should reduce leaks and extend service life. Constructed from metal with rubber sections and supplied with new clips, the part is application specific and engineered to match original routing and mounting points for compatible vehicles. Real-world feedback shows generally good fit and durability but occasional fitment or end-size mismatches on some years that may require minor modification or careful verification before installation. Installation can require radiator fan removal and coolant handling, so expect a few hours of labor if you do the job yourself. This is a quality-focused replacement that aims to improve long-term reliability where fitment is correct.
Best for: Performance-oriented buyers who prioritize a longer-lasting, factory-quality cooling line replacement and are comfortable verifying fitment or performing a more involved installation.
Less Ideal for: Buyers seeking a universal or drop-in part for multiple makes and years or those unwilling to handle time-consuming installation should consider other options or professional fitting services.
- Crimped hose-to-metal connection improves resistance to corrosion-related leaks compared with spring-clamp designs
- Made to match original routing and mounting points for direct replacement on specified vehicles
- Includes new clips and quick-connect fittings to simplify reattachment during installation
- Durable metal and rubber construction designed for long service life under operating pressure
- Not guaranteed to fit every model year exactly; some users reported needing to modify or confirm end sizes before installation
- Installation can be labor intensive and may require radiator fan removal and partial coolant draining
Verdict A sturdier, corrosion-resistant replacement cooler line built for durability when fitment is confirmed, but expect a hands-on install if modifications are needed.
4. Byredio AN6 Braided Fuel/Transmission Hose 20 ft
| Size | AN6 20FT |
|---|---|
| Maximum Pressure | 500 Pound per Square Inch |
| Material | Nylon braided with 304 stainless steel |
| Temperature Range | -40F to 248F |
This Byredio AN6 hose is a long, flexible braided line intended for high-pressure fuel, oil, and transmission fluid use. It is typically cut to length and routed where factory lines are replaced or upgraded, and the woven nylon outer braid plus stainless steel layer gives improved abrasion resistance and a braided look. The hose claims a 500 PSI working pressure and temperature tolerance from about -40F to 248F, which makes it suitable for many engine bay and transmission cooler runs on a G37 where moderate pressure and heat resistance are needed. Installation is straightforward when used with AN fittings or proper clamps since the tubing bends more easily than rigid metal lines. Important limitations are that it is not rated for E85, the outer nylon braid can fray if trimmed and may need tape or heat-shrink at clamp points, and the listing does not include pre-terminated fittings so additional connectors are required for a finished transmission cooler installation.
Best for: Budget-conscious Infiniti G37 owners who want an affordable, flexible line for replacing or extending a transmission cooler hose and prefer to do their own cutting and fitting.
Less Ideal for: Users who need a ready-to-install hose with pre-attached fittings or those running E85 who require ethanol-rated lines should consider other options.
- Long 20 ft length allows one-hose runs and custom routing for cooler loops
- 500 PSI working pressure suitable for most transmission cooler and fuel-return applications
- Flexible braided construction makes routing around tight engine-bay geometry easier
- Temperature range and material compatibility cover common transmission fluids and oils
- Not compatible with E85 fuel according to the manufacturer
- No fittings included so you must source AN fittings or compatible connectors separately
- Outer nylon braid may fray when cut and can require finishing to avoid wear
Verdict A cost-effective, flexible AN6 braided hose that works for many G37 transmission cooler jobs if you supply fittings and avoid E85.
5. Generic 70" Stainless Steel Braided AN6 Transmission Cooler Line Kit
| Material | Stainless Steel/PTFE |
|---|---|
| Length | 70 Inches |
| Fitting Size | AN6 |
| Nominal Wall Thickness | 0.0375 inches |
This kit supplies two 70-inch stainless steel braided PTFE lines with AN6 fittings and multiple 90-degree adapters so you can route transmission fluid to a cooler or replace deteriorated hard lines. It is typically used when adding an auxiliary cooler for towing or when existing cooler lines are corroded and leaking. The stainless braid and PTFE liner provide corrosion resistance and flexibility, while included fittings and bends aim to simplify hookup. In practice the kit works well on cars that accept AN6 plumbing, and reviewers report it holds high pressure and installs neatly with common hand tools. Expect to source a few extra fittings for some factory setups because the kit is universal rather than vehicle-specific, and quality control has occasional issues like incorrect length or rough threads on fittings. For a risk-averse buyer this kit lowers the cost of a DIY cooler retrofit but may require verifying connector types and having a couple of adapter fittings on hand to ensure a leak-free, factory-quality connection.
Best for: A risk-averse mainstream buyer who wants a cost-effective way to add or replace transmission cooler lines while minimizing the chance of heat-related transmission failure through a proven cooling upgrade.
Less Ideal for: Buyers who prefer a plug-and-play, vehicle-specific factory-quality replacement with guaranteed connector compatibility should consider purpose-built lines or OEM-style assemblies instead.
- Stainless steel braided exterior with PTFE liner for corrosion resistance and flexibility.
- Includes 90-degree AN6 fittings and bends to simplify routing to a cooler.
- Long 70" length suitable for routing from many transmission locations to an aftermarket cooler.
- Reported to handle high hydraulic pressure without leaking when properly installed.
- Universal AN6 fittings mean additional adapters may be required to match some factory connector types.
- Quality control varies with occasional wrong lengths or fittings that require cleanup.
- Not a vehicle-specific kit so fitment and ideal connector selection are left to the installer.
Verdict A budget-friendly universal AN6 braided line kit that improves cooling potential but may need extra adapter fittings and inspection to achieve a factory-quality installation.
6. MuHize Stainless Steel Braided Transmission Cooler Line Kit, 70-inch
| Hose length | 70 Inch |
|---|---|
| Inner material | PTFE (Teflon) |
| Outer material | Stainless Steel braid |
| Included fittings | AN-6 and assorted NPT adapters |
| Package quantity | 2 hoses |
This MuHize kit supplies two 70-inch PTFE-lined, stainless-steel braided transmission hoses plus a broad selection of AN-6 and NPT adapter fittings intended to connect an inline cooler or radiator-mounted cooler to a transmission. It is typically used when replacing corroded hard lines or installing an external cooler on vehicles that use flared or AN-style connections. The braided outer jacket and PTFE core resist heat, oil exposure, and corrosion, and the included adaptors and 4L80E fittings reduce the need to source extra hardware. Real-world benefits are clean, flexible routing away from exhaust and improved durability versus factory rubber lines. Limitations are that the kit is a universal-length solution not specific to the Infiniti G37 and may require trimming or extra clamps for a tidy install, and some buyers report mismatched fittings on less common transmissions so careful fit verification is required before installation.
Best for: Practical optimizers who want a durable, hardware-rich cooler line kit to convert to an aftermarket cooler and prefer solving fitment with trimming and adapters rather than buying vehicle-specific lines.
Less Ideal for: Buyers seeking a drop-in, vehicle-specific replacement built to Infiniti G37 factory connection sizes should look for a dedicated OEM-style line designed for that model.
- PTFE inner hose with stainless steel braid for heat and corrosion resistance
- Includes multiple AN-6 and NPT adapter fittings to cover common cooler connections
- Two 70-inch hoses provide generous length for flexible routing
- Braided construction is more abrasion-resistant than factory soft lines
- Kit is a universal fit and may need cutting or additional clamps to suit specific vehicle routing
- Not tailored to Infiniti G37 factory fittings so adapters must be checked for compatibility
Verdict A cost-effective, heavy-duty universal kit that gives practical installers the fittings and length needed to add or replace cooler lines, but expect to verify and adapt fittings for the Infiniti G37.
7. EVIL ENERGY 6AN Braided Transmission Cooler Line Kit, 15 ft
| Material | Cpe Rubber inner with nylon braid and 304 steel wire |
|---|---|
| Hose ID | 0.31 inches |
| Maximum Pressure | 750 Pound per Square Inch |
| Length | 15 Feet |
This EVIL ENERGY 6AN braided line kit supplies 15 feet of nylon-braided, steel-reinforced CPE hose plus a selection of swivel hose ends and adapter fittings intended for a transmission cooler installation. For an Infiniti G37 owner installing an aftermarket transmission cooler, the kit provides flexible lines that resist kinking, a high working pressure rating, and several common swivel ends including straight and 90-degree fittings to route lines around tight engine-bay spaces. The braided outer layer and 304 steel wire reinforcement reduce abrasion and help the hose hold up to heat and vibration near the transmission. Included aluminum alloy fittings simplify connections and give a finished look under the hood. Limitations to note are that some buyers reported missing or mismatched transmission-specific fittings, so you may need to source a G37-specific adapter for a perfect fit, and the kit does not include vehicle-specific installation instructions. If you want a mostly complete, durable hose-and-fitting set to pair with a G37 transmission cooler, this kit covers the basics but plan for a possible extra adapter or two.
Best for: Balanced owners who want a durable, mostly complete hose-and-fitting kit to install an aftermarket transmission cooler on an Infiniti G37 and who value flexibility and a finished look under the hood.
Less Ideal for: Buyers who want a plug-and-play, vehicle-specific transmission hose solution with guaranteed G37-fit adapters and step-by-step instructions should consider a dedicated G37 kit or OEM-style lines instead.
- 15 feet of braided, steel-reinforced hose for routing to a transmission cooler
- High maximum working pressure rating suitable for transmission fluid lines
- Includes a variety of swivel hose ends and adapter fittings for common routing scenarios
- Braided outer layer and nylon braid improve abrasion and heat resistance
- May not include every Infiniti G37-specific adapter so additional fittings could be required
- No vehicle-specific installation instructions or guaranteed fitment for the G37
Verdict A durable, flexible 15-foot braided 6AN hose kit that covers most transmission cooler routing needs for an Infiniti G37 but may require an extra G37-specific adapter for perfect fitment.
Choosing the Right Infiniti G37 Transmission Cooler Line: Key Factors to Consider
Material and Construction
The line material determines how well it resists corrosion, heat, and mechanical wear. Metal hard lines usually offer superior long-term resistance to abrasion and puncture, while reinforced rubber hoses can absorb vibration and are often easier to route in tight spaces.
Construction quality includes wall thickness, reinforcement layers in hoses, and the finish or coating on metal lines. These aspects influence how the line handles thermal cycling and road exposure, which in turn affects longevity and leak risk.
Fitting Type and Sealing
Fittings and seals are frequent failure points, so pay attention to the connection style and whether the kit includes new O-rings or sealing washers. Properly sized flare fittings, crimped hose ends, or threaded adapters must match the vehicle's factory attachment points to avoid weeping joints.
A design that supplies upgraded or reusable fittings can simplify future maintenance and reduce the chance of seepage at junctions. Check whether fittings are plated or corrosion-resistant to maintain a reliable seal over time.
Fitment and Vehicle Specificity
Exact fitment for the Infiniti G37 matters for a clean installation and to prevent kinks or undue stress. Lines designed specifically for the vehicle will follow factory routing, use the correct mounting brackets, and align with transmission and cooler ports without forceful bending.
Using a part without precise G37 compatibility can lead to rubbing on chassis components, restricted fluid flow, or premature wear from vibration. Look for product notes that specify G37 model years or include vehicle-specific mounting hardware.
Ease of Installation and Maintenance
Consider how straightforward the replacement is, especially if you plan to do the work yourself. Preformed lines and complete trans cooler line kits that include hoses, clamps, and fittings reduce the need for additional parts and minimize installation time.
Designs that allow section replacement or offer compression-style fittings make future repairs simpler. Also factor in whether standard tools are sufficient and if the line requires special flaring or crimping equipment.
Durability Under Heat and Vibration
Transmission lines are exposed to engine heat and constant vibration, so choose materials and assemblies that tolerate thermal expansion and mechanical stress. Look for reinforcement in hoses and vibration-dampening features in the mounting points to reduce fatigue failures.
A construction that accommodates repeated heating and cooling cycles without hardening, cracking, or loosening at joints will generally provide better long-term reliability and fewer leaks.
Serviceability and Repair Options
Evaluate whether the line can be serviced if it develops a leak or damage. Some assemblies allow for replacing only a hose section or a fitting, while others require swapping the entire run. Availability of compatible replacement fittings, hose ends, and repair kits is useful for quick trans cooler line leak repair.
Choosing a line with commonly available fittings and straightforward routing helps reduce downtime and makes future maintenance less expensive and time-consuming.
FAQ
What are common symptoms of a failing transmission cooler line on an Infiniti G37?
Common signs include visible fluid leaks under the vehicle near the transmission area, a low transmission fluid level, or overheating transmission temperatures. You may also notice a burning smell or poor transmission shifting. These symptoms often point to a compromised cooler line but can have other causes, so inspect connections and hoses carefully.
Can I replace a transmission cooler line myself on the Infiniti G37?
Many owners can perform the replacement with basic mechanical skills, standard hand tools, and proper safety precautions. Successful DIY replacement depends on correct fitment, access to the line routing, and the ability to properly seal fittings. If routing is tight or special flaring tools are required, professional installation may be advisable.
Should I choose a hard line or a rubber hose for the cooler line?
Hard lines offer greater resistance to abrasion and puncture, while rubber hoses can better absorb vibration and are easier to route. The right choice depends on the G37's routing constraints and your priorities for durability versus flexibility. Many effective solutions combine both types for optimal performance.
How do I stop a small leak in a transmission cooler hose temporarily?
For a short-term fix, a hose clamp with a rubber patch or an approved repair sleeve can help contain a small seep until a full replacement is done. These measures are temporary and should be followed by a proper repair or part replacement to ensure lasting safety and performance.
What should I look for in fittings when replacing the cooler line?
Ensure fittings match the G37 transmission and cooler ports in thread type, flare angle, or barbed profile. Look for corrosion-resistant finishes and included sealing hardware such as new O-rings or crush washers. Properly matched fittings reduce the chance of leaks and simplify installation.
How often do transmission cooler lines need replacement?
There is no fixed interval, as replacement depends on exposure, material quality, and driving conditions. Regular inspections during service for signs of wear, cracking, or corrosion will indicate when replacement is needed. Addressing issues early helps prevent fluid loss and transmission damage.
How We Chose the Best Infiniti G37 Transmission Cooler Line
We evaluated candidate transmission cooler lines for the Infiniti G37 by applying vehicle-specific fitment checks and focusing on durability, sealing reliability, and ease of installation. Primary criteria included material construction (aluminum, steel, or reinforced rubber hose), corrosion and abrasion resistance for road-salt and heat exposure, and the quality of fittings and crimps that affect long-term leak prevention. We also considered repair-friendliness, such as whether the design allows for straightforward hose or fitting replacement, and whether a complete kit is available for an end-to-end swap. Performance under repeated thermal cycling and vibration was reviewed conceptually to prioritize options less likely to develop stress cracks or fatigue leaks. We excluded parts lacking clear Infiniti G37-specific fit information, items with ambiguous or missing fitting details, and any components intended for different vehicle models. The final list emphasizes products that balance robust materials, correct G37 fitment, and practical installation features that matter for everyday ownership.
Our full evaluation process is outlined in our review methodology.
Conclusion
When choosing an Infiniti G37 transmission cooler line, prioritize correct fitment and robust construction to minimize leak risk and ensure reliable cooling. Balance material choices with the vehicle's routing needs, and give extra weight to quality fittings and corrosion resistance. Accept that some tradeoffs exist between ease of installation and long-term durability. Selecting a solution that matches how you drive and how comfortable you are with maintenance will lead to the best long-term outcome for the transmission.
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