What temperature should a 5.7 Hemi thermostat be?
For most 5.7L Hemi engines, the standard thermostat rating is 180°F (82°C). Some variants or aftermarket replacements use 195°F (90°C), while 160°F is not typical for stock operation. Always verify the exact specification for your vehicle from the owner's manual or OEM parts guide.
Why thermostat temperature matters
The thermostat controls the engine’s warm-up rate and the steady operating temperature. A thermostat that opens too early or too late can affect cabin heat, fuel efficiency, emissions, and engine wear. Getting the right rating helps the engine reach and maintain its ideal temperature quickly and reliably.
Common thermostat ratings for the 5.7 Hemi
Before listing typical options, note that different model years and configurations may use slightly different specs. The following ratings are commonly encountered when replacing a 5.7 Hemi thermostat.
- 180°F (82°C) – The most common rating for stock 5.7 Hemi engines; balances quick warm-up with stable operating temperature.
- 195°F (90°C) – A higher-rating option used in some models or aftermarket setups; can push operating temperature higher and may be chosen for hot climates or specific towing requirements.
- 160–170°F (71–77°C) – Rare for stock 5.7 Hemi in daily driving; may appear in special applications but is not typical and can affect warm-up time and cabin heat.
Concluding note: For standard daily driving, 180°F remains the baseline for the 5.7 Hemi, with 195°F as a potential alternative in certain climates or load conditions. Always confirm with the exact vehicle specifications.
How to determine the correct thermostat for your vehicle
To ensure you select the right thermostat for your 5.7 Hemi, follow these steps:
- Check your vehicle’s VIN and model year to confirm the engine spec and factory recommendations.
- Consult the owner's manual or a factory service manual for the thermostat rating recommended for your exact configuration.
- Inspect the current thermostat or the replacement part you’re considering; the rating is often stamped on the thermostat housing or body.
- Consider climate and use case (hot climates, towing, or heavy loads may influence the preferred rating).
- Purchase an OEM-approved part or a reputable aftermarket thermostat rated to your spec (180°F is the common default).
Concluding: Verifying the exact specification for your vehicle ensures you maintain proper operating temperature, fuel efficiency, and performance. When in doubt, replace with the OEM-recommended rating for your model year.
When replacing and testing
After installation, verify the thermostat opens at the rated temperature and that the engine reaches its normal operating temperature without overheating. Use a reliable infrared thermometer or a scan tool to monitor coolant temperature and compare it to the thermostat’s rating. If the gauge remains high or low, or if there are persistent heat-related symptoms, recheck installation and part spec.
Model-year and vehicle variations
Variations exist across Ram trucks, Jeeps, and Chryslers that use the 5.7 Hemi. While 180°F is widely standard, certain trims or climates may employ a 195°F thermostat as part of dealer or aftermarket options. Always cross-check with the specific model’s documentation to confirm the correct rating for your exact vehicle.
Summary
The typical thermostat for a 5.7 Hemi is 180°F (82°C), with 195°F (90°C) as a secondary option in some configurations. 160–170°F is uncommon for stock operation. For accuracy, verify the exact rating from the vehicle’s VIN, owner's manual, or OEM parts guide, and replace with a part rated to your specific configuration and climate needs.
Bottom line: If you own a 5.7 Hemi, start with a 180°F thermostat unless your manual or dealer specifies a different rating for your model year and climate. Regular checks after replacement help ensure the engine runs at its optimal temperature.
