HomeBelts and Cooling > Radiators, Coolers and Related ComponentsDorman 603-346 Engine Coolant Reservoir - Front
Part #: 603-346

Dorman 603-346 Engine Coolant Reservoir - Front

Front
⚙️ 14 vehicles fit this part
🔍
Select your vehicle to confirm fitment
Verify this part fits before purchasing — free returns if it doesn't
$168.33Free Shipping
🚚Free ShippingNo Cost to Continental U.S.
🔄Free Returns*Wrong fit? No cost
🛡️60-Day ReturnsMoney back guarantee
*Free return shipping only qualifies if our fitment verification tool is used.
🔥
✅ In Stock · Ready To Ship Most orders ship same-day if ordered before 1pm CST.
OE Direct Replacement — Bolt-on fit, no modifications needed
🚗Fitment: Ford and Mercury, Escape and Mariner
🔄Easy Returns — Return within 60 days for a full refund
🚚Fast Shipping — Most orders ship same business day before 1pm CST

Overview of Dorman Engine Coolant Reservoir for Ford Escape and Mercury Mariner

The Dorman 603-346 engine coolant reservoir is designed specifically for Ford Escape and Mercury Mariner models. This replacement reservoir ensures proper coolant storage and pressure management within your vehicle's cooling system.

  • Constructed from durable white plastic for corrosion resistance
  • Includes a spring loaded twist cap rated for 17 psi maximum pressure
  • Pressurized design to maintain optimal cooling system performance
  • Comes with one coolant reservoir and one cap included
  • Features two mounting holes for secure installation (mounting hardware not included)

Detailed Product Description

The Dorman 603-346 engine coolant reservoir is engineered to meet the specifications required by Ford Escape and Mercury Mariner vehicles. Made from sturdy plastic, this white reservoir is built to withstand the heat and pressure of the engine cooling system. The included spring loaded twist cap is designed to maintain a maximum pressure rating of 17 psi, helping to prevent coolant loss and overheating. Although mounting hardware and brackets are not included, the reservoir features two mounting holes to facilitate proper attachment using existing vehicle components.

Common Applications and Problem Resolution

  • Replacement for cracked or leaking coolant reservoirs in Ford Escape and Mercury Mariner
  • Addresses coolant overflow and loss due to damaged or faulty reservoirs
  • Helps maintain proper system pressure to prevent engine overheating
  • Resolves issues related to coolant contamination from compromised reservoir caps
  • Supports cooling system integrity after accident damage or wear

Installation Notes and Tips

When installing the Dorman 603-346 engine coolant reservoir, ensure the vehicle is cool to avoid injury from hot coolant. Use the existing mounting hardware or brackets from the original reservoir, as this product does not include them. Verify that the spring loaded twist cap is securely tightened to maintain system pressure. Inspect hoses and connections for wear or damage during installation to ensure a complete and reliable repair.

Quality Assurance and Warranty Information

Dorman parts are manufactured to meet or exceed OEM standards for fit and function. The 603-346 engine coolant reservoir undergoes quality checks to ensure durability and performance in Ford Escape and Mercury Mariner vehicles. Warranty coverage details can be obtained from Dorman directly or through authorized distributors.

BrandDorman
Part Number603-346
Cap IncludedYes
Cap Maximum Pressure Rating17
Cap TypeSpring Loaded Twist
ColorWhite
MaterialPlastic
Mounting Brackets IncludedNo
Mounting Hardware IncludedNo
Mounting Hole Quantity2
Package Contents1 Coolant Reservoir; 1 Cap
PressurizedYes

This part fits 14 vehicles. Search below:

YearMakeModelLitersCylindersFuel TypePositionNotes
2012FordEscape2.5LL4ELECTRIC/GASFront
2011FordEscape2.5LL4ELECTRIC/GASFront
2011MercuryMariner2.5LL4ELECTRIC/GASFront
2010FordEscape2.5LL4ELECTRIC/GASFront
2010MercuryMariner2.5LL4ELECTRIC/GASFront
2009FordEscape2.5LL4ELECTRIC/GASFront
2009MercuryMariner2.5LL4ELECTRIC/GASFront
2008FordEscape2.3LL4ELECTRIC/GASFront
2008MercuryMariner2.3LL4ELECTRIC/GASFront
2007FordEscape2.3LL4ELECTRIC/GASFront
2007MercuryMariner2.3LL4ELECTRIC/GASFront
2006FordEscape2.3LL4ELECTRIC/GASFront
2006MercuryMariner2.3LL4ELECTRIC/GASFront
2005FordEscape2.3LL4ELECTRIC/GASFront

* Always verify fitment with your vehicle's VIN if unsure. Submodel & trim restrictions may apply.

This part directly replaces or is cross-referenced with the following part numbers:

5M6Z8A080AC

Cross-reference numbers are provided for identification purposes only. Always confirm fitment before ordering.