Pyro ??

[kaylabryn]

I put a new Pyro in not very long ago and am not sure that it is reading correctly. When it is cold it never goes bellow 100 F, even though it is 50 F outside. Driving things seem somewhat normal I am reading between 400 and 500 around town empty, and 550 or so flat empty on the highway 70mph. My vehicle is an 1995 suburban 2500 4x4, 3.73 gears auto. The gauge is an autometer and am wondering if I shoud send it back to them. Thank in advance.

[JohnC]

A pyrometer doesn't measure absolute temperature. It measures the difference in temperature between the "hot" end (the probe) and the "cold" end (the gauge). Most pyrometers come in one of two flavors: Regular and Snowmobile. The "regular" ones are calibrated for an ambient temperature of about 72* and the Snowmobile varient is calibrated for about 20*. You apparently have the former, and any time both ends are the same temp (cold engine) it will say about 72*, even if it's really 40 below...