How to service the thermostat on a 3.8L engine on 2003 Ford Mustang?

Service of the 3.8L engine thermostat starts by draining the engine coolant. Begin by disconnecting the upper radiator hose from its position on the coolant hose then remove the thermostat housing by unfastening its bolts. Clean and inspect the water outlet connection before getting rid of the thermostat. Move on to replace the old gasket before cleaning and checking both parts that need to mate. Thermostat mating surfaces located at both the engine and the water outlet need proper inspection. A critical installation step of replacing a thermostat involves repositioning it at its origin because it operates on an indexed mechanism. It is necessary to apply gasket adhesive on both the new thermostat gasket and to make sure the O-ring gasket fits properly around the thermostat. Complete the installation by performing an opposite sequence to the removal steps then add cooling system fluid.

OEM 2003 Ford Mustang Thermostat

Engine Coolant Thermostat

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4 Thermostats found

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2003 Ford Mustang Thermostat
Part Number: 7L3Z-8575-E
$20.68 MSRP: $32.00
You Save: $11.32 (36%)
Ships in 1 Business Day
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Product Specifications
- Other Name: Thermostat Assembly; Engine Coolant Thermostat; Thermostat, Coolant
- Replaces: 7L3Z-8575-D, 7L3Z-8575-B, AL3Z-8575-B, RT-1196, RT-1230, 3L3Z-8575-AA, 3L3Z-8575-AC, 7L3Z-8575-C, AL3Z-8575-A, RT-1204, RT-1234, RT-1178, RT-1229, RT-1165
- Condition: New
- Fitment Type: Direct Replacement
- SKU: 7L3Z-8575-E
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following 2003 Ford Mustang Submodels:
- Bullitt, GT, GT Bullitt, Shelby GT | 8 Cyl 4.6 L GAS
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2003 Ford Mustang Thermostat
Part Number: F5OY-8575-A
$12.85 MSRP: $20.40
You Save: $7.55 (38%)
Ships in 1-2 Business Days
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Product Specifications
- Other Name: Thermostat Assembly
- Base No.: 8575
- Item Weight: 0.40 Pounds
- Item Dimensions: 3.9 x 2.3 x 2.4 inches
- Condition: New
- Fitment Type: Direct Replacement
- SKU: F5OY-8575-A
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
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Fits the following 2003 Ford Mustang Submodels:
- GT, SVT Cobra | 8 Cyl 4.6 L GAS
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2003 Ford Mustang Thermostat
Part Number: KU2Z-8575-B
Product Specifications
- Other Name: Thermostat Assembly; Engine Coolant Thermostat
- Replaces: F6DZ-8575-AA, F6ZZ-8575-A, F8DZ-8575-AA
- Condition: New
- Fitment Type: Direct Replacement
- SKU: KU2Z-8575-B
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following 2003 Ford Mustang Submodels:
- Base | 6 Cyl 3.8 L GAS, 6 Cyl 3.9 L GAS
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2003 Ford Mustang Thermostat
Part Number: F5OZ-8575-AA
Product Specifications
- Other Name: Thermostat Assembly
- Base No.: 8575
- Item Weight: 0.40 Pounds
- Item Dimensions: 2.2 x 2.2 x 2.4 inches
- Condition: New
- Fitment Type: Direct Replacement
- SKU: F5OZ-8575-AA
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
More Info
Fits the following 2003 Ford Mustang Submodels:
- GT, Mach 1, SVT Cobra, SVT Cobra 10th Anniversary | 8 Cyl 4.6 L GAS

2003 Ford Mustang Thermostat

If you're seeking quality and affordability, look no further than our extensive inventory of genuine 2003 Ford Mustang Thermostat available at FordPartsDeal.com. You can confidently purchase our OEM 2003 Ford Mustang Thermostat as they are supported by the manufacturer's warranty and our hassle-free return policy, alongside the benefit of our fast delivery service.

2003 Ford Mustang Thermostat Parts Questions & Experts Answers

Q: How to service the thermostat on a 3.8L engine on 2003 Ford Mustang?
A: Service of the 3.8L engine thermostat starts by draining the engine coolant. Begin by disconnecting the upper radiator hose from its position on the coolant hose then remove the thermostat housing by unfastening its bolts. Clean and inspect the water outlet connection before getting rid of the thermostat. Move on to replace the old gasket before cleaning and checking both parts that need to mate. Thermostat mating surfaces located at both the engine and the water outlet need proper inspection. A critical installation step of replacing a thermostat involves repositioning it at its origin because it operates on an indexed mechanism. It is necessary to apply gasket adhesive on both the new thermostat gasket and to make sure the O-ring gasket fits properly around the thermostat. Complete the installation by performing an opposite sequence to the removal steps then add cooling system fluid.