2019 Ram 1500 Classic Coolant Temperature Sensor: A Complete Guide
Understanding the signs of a failing coolant sensor and how to replace it on your Ram truck.
- A failing coolant temp sensor can cause poor fuel economy, overheating, and a check engine light with codes like P0117, P0118, or P0128.
- Replacement is a simple DIY task for most owners, taking about 30 minutes with basic tools.
- For gasoline engines, there are no major recalls for this sensor, but be sure to diagnose the issue properly, as a bad thermostat can cause similar symptoms.
- The sensor is located on the front of the water pump for the 5.7L Hemi and on the rear driver's side of the block for the 3.6L V6.
Is a Failing Coolant Sensor a Big Deal?
A failing Engine Coolant Temperature (ECT) sensor can cause more than just a wrong reading on your dash. The truck's computer relies on this sensor for important engine adjustments. A bad sensor can lead to poor engine performance, lower fuel economy, and even engine overheating. Ignoring these symptoms could lead to more serious engine problems. Common trouble codes that trigger the check engine light include P0117 (sensor circuit low), P0118 (sensor circuit high), and P0128 (coolant temperature is below what it should be).
Known Issues, Recalls, and TSBs
As of early 2026, there are no specific recalls or Technical Service Bulletins (TSBs) from Ram or the NHTSA for the Engine Coolant Temperature Sensor on the 2019 Ram 1500 Classic with gasoline engines. However, there is a significant recall (NHTSA 19V-757) for 2014-2019 Ram 1500 models equipped with the 3.0L EcoDiesel engine. This recall addresses a cracking EGR cooler that can leak coolant, which could lead to a fire in the intake manifold. This issue does not apply to the 3.6L V6 or 5.7L V8 gasoline engines.
Choosing the Right Aftermarket Sensor
When it's time for a replacement, you don't have to buy the original Mopar part to get a quality sensor. Many aftermarket brands meet or exceed the original specifications. For a simple but critical part like the ECT sensor, a quality aftermarket brand provides a good balance of performance and value. Brands like Standard Motor Products, Delphi, or NGK are known for making reliable parts that are often used by car manufacturers themselves. Cheaper, value-based brands are also available and can be a good option for a budget-friendly repair.
Pro Tip: Check the Connector and Material
Before you buy, it's wise to look at your truck's current sensor connector. While most are standardized, slight differences in plastic housings can make them hard to plug in. Also, many aftermarket sensors for the Ram 1500 Classic have a brass body, which is often seen as an upgrade over the original all-plastic sensors on some models.
Cost of Replacing a 2019 Ram 1500 Classic Coolant Temperature Sensor
| Part Type | Estimated Cost |
|---|---|
| New Aftermarket | $15 - $40 |
| New OEM (Mopar) | $30 - $80 |
| Shop Labor | $50 - $100 |
Frequently Asked Questions
Where is the coolant temperature sensor located on the 2019 Ram 1500 Classic?
On the 5.7L V8 Hemi engine, the sensor is on the front of the engine, threaded into the water pump assembly near the thermostat housing. For the 3.6L V6 engine, it is in a tougher spot on the driver's side of the engine block toward the rear. Access is often easiest by removing the driver's side front wheel and the plastic fender liner.
Can I replace the coolant temperature sensor myself?
Yes, this is a DIY-friendly job for most home mechanics. It requires basic hand tools and can usually be done in about 30 minutes. Be sure the engine is completely cool before starting.
Will I lose a lot of coolant when I change the sensor?
You will lose a small amount of coolant when you remove the old sensor. If you have the new sensor ready to install right away, the loss will be minimal. You can top off the coolant reservoir afterward if needed. Make sure to use the correct Mopar OAT coolant (meeting specification MS.90032) for your Ram.
My temperature gauge is fluctuating. Is it the sensor?
It could be, but it's often the thermostat. Ram 1500 Classic trucks are known to have temperature fluctuations between 195°F and 210°F as the thermostat opens and closes, which is considered normal by many owners. If you get a P0128 code, it's more likely that the thermostat is stuck open rather than a bad sensor.
Helpful Videos
Technical Specifications
OEM Part Numbers: 5149077AB 68164627AA 5149096AB
Typically a 2-pin, blade-type sensor that threads into the engine block or water pump housing.
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Ram 1500 Classic: