What size thread is a GM air temperature sensor?
In many GM vehicles, the air temperature sensor (IAT) threads into the intake tract or throttle body, and the correct thread size depends on the exact model and engine family. In most GM engines you'll encounter a 1/4-28 UNF thread, but some newer designs use a metric M12x1.5 thread. Always verify with your vehicle's service manual or OEM parts to ensure a proper fit.
Common thread sizes
These are the sizes you are most likely to encounter on GM air temperature sensors. Variations can occur by model year and engine family.
- 1/4-28 UNF thread (the most common size for many GM IAT sensors installed in intake plenums, throttle bodies, and duct fittings).
- M12x1.5 thread (used by some newer GM designs and certain outside-air temperature sensors in climate-control systems).
In practice, you may find other thread forms in rare GM applications; when in doubt, check the service manual for your exact VIN or measure the port and the sensor threads to be sure.
How to verify the correct size for your vehicle
To ensure you get the right thread size for your GM air temperature sensor, follow these steps:
- Identify your exact vehicle year, make, model, and engine family; consult the GM service manual or parts catalog for the IAT sensor specifications.
- If you can access the sensor, gently remove it from the intake or throttle body and inspect the threads.
- Measure the thread diameter and pitch: a diameter near 0.25 inches with 28 threads per inch indicates 1/4-28 UNF; a metric 12 mm outer diameter with about 1.5 mm pitch corresponds to M12x1.5.
- Compare with the replacement part packaging or GM OEM part number to confirm compatibility.
- When ordering from a parts store, provide your VIN and engine to ensure the correct thread size is selected.
Once you have confirmed the correct size, install the sensor carefully and test for proper sealing and electrical connection.
Summary
Thread size for GM air temperature sensors is not universal. The two most common formats are 1/4-28 UNF and M12x1.5. Always verify with vehicle-specific service data or the OEM part to avoid cross-threading or leaks. If in doubt, consult a GM dealership or a qualified technician for confirmation and installation guidance.
