For DIY car enthusiasts tackling a Subaru CVT fluid change, maintaining the correct transmission fluid temperature is critical. Operating outside the recommended range (95°F to 113°F) during the process can lead to serious transmission damage. Ideally, a Bluetooth OBD2 scanner paired with a smartphone app offers a direct and reliable way to monitor CVT fluid temperature. High-end, dedicated scanners also provide this functionality, making temperature monitoring straightforward for those with the right equipment.
However, for individuals without access to these tools, or those seeking a more budget-friendly option, infrared (IR) thermometers, or IR guns, have emerged as a seemingly popular alternative. Priced around $20 and readily available, IR guns offer a quick and easy way to take temperature readings. Yet, questions linger about their reliability in accurately measuring CVT fluid temperature through the transmission pan.
The accuracy of IR thermometers is influenced by several factors. Correct emissivity settings for the target material are crucial, as are the distance from the target and the surface condition – flat and non-reflective surfaces are optimal. Ambient temperature can also play a role in reading accuracy.
Considering the precision of OBD2 scanners in measuring CVT fluid temps, a pertinent question arises: Can IR gun readings be validated or calibrated against OBD2 scanner data to achieve acceptable accuracy? Has anyone explored developing a “correction factor” to adjust IR gun readings to align with the more precise measurements from OBD2 scanners?
To investigate this, one could control for variables affecting IR gun accuracy. This includes setting the emissivity to match the belly pan material (approximately 0.30 for aluminum and 0.80 for steel), maintaining a consistent distance, ensuring readings are taken on a flat surface, perhaps even painting a spot black to improve emissivity, and noting the ambient temperature. By conducting comparative tests, measuring CVT fluid temperature simultaneously with both an OBD2 scanner and an IR gun under these controlled conditions, it might be possible to establish a correlation. Documenting this data in a chart or graph could provide a practical guide for using IR guns to measure CVT temperature with reasonable confidence.
This approach could be particularly beneficial for DIYers who seek an affordable alternative to expensive scanning tools. While IR guns themselves are inexpensive, understanding their limitations and potentially developing a calibration method could make them a more viable option for ensuring accurate CVT fluid temperature readings during maintenance. Has anyone in the DIY community undertaken such an experiment to create a practical guide or formula for using IR thermometers in this context?
