Mishimoto 79°C Low-Temperature Thermostat - Dodge 5.9L 12v Cummins 1989-1993

Mishimoto low-temperature thermostat for the 1989-1993 first-gen Dodge D250 / D350 / W250 / W350 5.9L 12-valve Cummins diesel. Its lower 174°F activation (vs. the 180°F factory unit) lets coolant flow through the radiator earlier to maintain lower temperatures — ideal for warm climates or extreme towing. Includes a replacement gasket, backed by the Mishimoto Lifetime Warranty.

Specifications

This part fits:

Shipping

• In-stock orders placed before 3 PM EST ship the same day — everything else ships within 24 hours.
• Standard, expedited, and overnight options at checkout.
• Oversized items ship by freight and take longer.
• Backordered items ship as soon as stock lands — contact us for lead times.
• International orders: prices do not include VAT, duties, or import fees. Your country charges these at import and they are the buyer’s responsibility.

Returns

• 30-day returns on new, uninstalled items in original packaging with all hardware.
• Standard returns: 8% restocking fee, buyer pays return shipping. Both waived if the item is defective or we made the error.
• Installed or used parts can’t be returned — confirm fitment before you install.
• Special orders and custom items are final sale.
• Email us for return authorization before shipping anything back.

Full details: Shipping Policy · Refund Policy