Mishimoto MMOC-GTO-04T 04-06 Pontiac GTO 5.7L/6.0L Thermostatic Oil Cooler Kit Silver

Mishimoto MMOC-GTO-04T Thermostatic Oil Cooler Kit for 2004-2006 Pontiac GTO LS1/LS2

The Mishimoto MMOC-GTO-04T is an engineered direct-fit thermostatic oil cooler kit for the 2004-2006 Pontiac GTO 5.7L LS1 and 6.0L LS2. LS engines are efficient and powerful, but sustained high oil temperatures accelerate wear and rob power. The MMOC-GTO-04T uses a 25-row stacked-plate cooler — Mishimoto's largest — to deliver up to 65 degrees F of oil temperature reduction during testing without the thermostat, with real-world drops keeping oil in the optimal operating range under track and street driving conditions. This MMOC-GTO-04T kit is backed by the Mishimoto Lifetime Warranty.

Key Features

• 25-row stacked-plate cooler — maximum core capacity for high-output LS1/LS2 engines
• Direct-fit oil line adapter — bolts to the GTO oil filter housing for clean, leak-free connections
• In-line thermostat — opens at 185 degrees F to allow oil to warm up before routing through the cooler, preventing overcooling in cold conditions
• Direct-fit thermostat bracket — mounts under the headlight using a dedicated bracket included in the MMOC-GTO-04T kit
• Stainless steel AN lines — kink-resistant and heat-tolerant, designed specifically for the GTO's tight engine bay routing
• Silver anodized finish — corrosion-resistant with clean appearance under the hood
• 65 degrees F temperature drop — recorded in Mishimoto's bench testing with constant flow through the cooler

What's Included

• 1x 25-row stacked-plate oil cooler
• 1x Direct-fit oil line adapter (oil filter housing mount)
• 1x In-line thermostat (opens at 185 degrees F) with direct-fit bracket
• AN stainless steel oil lines
• All mounting hardware and fittings
• Mishimoto installation instructions

Specifications

This Part Fits

Frequently Asked Questions

• Q: What is the difference between the MMOC-GTO-04T and the non-thermostatic version?
  A: The MMOC-GTO-04T includes an in-line thermostat that keeps oil flowing through the engine until it reaches 185 degrees F before routing it through the cooler. This prevents overcooling in cold climates and short drives.
• Q: Why doesn't this kit use a sandwich plate thermostat like other Mishimoto kits?
  A: The GTO's oil filter housing location makes a traditional sandwich plate impractical. The MMOC-GTO-04T instead uses a direct-fit oil line adapter at the filter housing and a remote-mount in-line thermostat bracket.
• Q: How much did oil temperatures drop during testing?
  A: Mishimoto's bench testing recorded a 65 degree F drop with oil constantly flowing through the cooler (thermostat bypassed). Real-world thermostatic operation will vary.
• Q: Will this fit both the LS1 5.7L and LS2 6.0L GTO?
  A: Yes. The MMOC-GTO-04T is engineered as a direct fit for the 2004-2005 5.7L LS1 and 2006 6.0L LS2 Pontiac GTO.
• Q: What warranty is included?
  A: The MMOC-GTO-04T is backed by the Mishimoto Lifetime Warranty.
• Q: Is professional installation required?
  A: No, but mechanical experience and basic AN fitting tools are recommended. Mishimoto provides a video installation guide for the MMOC-GTO-04T.
• Q: Will the oil cooler fit behind the front fascia without modification?
  A: The MMOC-GTO-04T is designed to fit within the GTO's engine bay using specific line routing that Mishimoto validated during R&D. Follow the included instructions for proper fitment.
• Q: Does Mishimoto test for Prop 65 chemicals in this kit?
  A: Products containing aluminum, rubber hoses, and metallic components may contain chemicals subject to California Prop 65 requirements.

Installation Instructions

Drain the engine oil and remove the oil filter. Install the direct-fit oil line adapter to the oil filter housing. Mount the oil cooler in the designated location. Install the in-line thermostat and bracket under the headlight per the Mishimoto instruction guide. Connect the AN stainless steel lines between the adapter, thermostat, and cooler. Reinstall the oil filter and refill with the appropriate engine oil. Start the engine and inspect all fittings for leaks. Recheck oil level after a warm-up cycle. Detailed video instructions are available on the Mishimoto website for MMOC-GTO-04T.

WARNING: This product can expose you to chemicals including lead and other compounds known to the State of California to cause cancer, birth defects, or other reproductive harm. For more information go to www.P65Warnings.ca.gov.