"Engine" Temperature Measurement.

[mockingbird812]

I need some input from some of the sage experts . I need to know a reliable and consistent method to confirm the temp of the engine coolant using an IR temp gun. I made some assumptions that:

1. GM knows where to place its temp sender unit to provide the best pickup point for measuring the coolant temperature at it pertains to monitoring engine operations.

2. When using an IR gun, you should measure at the same point on the engine as GM does (at the temp sending unit) in order to cooroborate the temp gauge (aftermarket mounted under the dash) read out.

What I noticed was that I have approximately three different IR temp readouts when taking measurements at the base, middle, and top (at wire lead) of the stock temp sending unit. The lowest temperature was at the base and the highest at the top. The range was approximately 22 degrees.

I am using a "Mannix" Infrared Thermometer (model # IRT2) which has a laser pointer built in. I stand approximately 3 to 4 feet from the intended point of measurement. Temperatures were recorded from a '69 L78 engine built to stock specifications.

Thanks!