Ever see one read absurdly high when you know it isn't right?

Yesterday, after like 2 minutes of idling the gauge read 240. I checked everything with my IR gun, I got about 80 degrees on the top radiator hose, about 120 on the surface of the heads.

-- Joe

 

Shorted causes a full-hot reading. Usually in the wiring somewhere. Disconnect it and play with it, see how the scanner reacts.

 

Hello,

It doesn't bury at 280 or whatever, it just reads way hotter than the IR.

Laptop connected to the ECM shows closer to actual (I believe) temp, but that's the CTS on the manifold vs the head. The head mounted CTS for the gauge is what I'm curious about.

Be it known, I have AFR heads so I have a adapter for the CTS (1/2" vs 3/8" NPT) . I wonder if it being stuck out a hair is picking up heat from the headers?

-- Joe

 

You can test for a short to ground on the guage sensor by grounding the lead and comparing the guage readings. Likely heat from the headers, as you surmise, if that's what's changed.

Factory guages are notorious for being out of whack too.

 

Just posted about this in another thread. My factory temp gauge was building resistance in the printed circuit. Not sure why, besides age. But I ended up running a simple electric coolant temp gauge off the head-mounted sending unit to get around this. Plan to do all autometer gauges someday anyway. Hope that helps

Will