Correct Temp Reading (IR gun)
Thread Starter
Burning Brakes
Joined: Sep 2002
Posts: 1,003
Likes: 38
From: Scottsdale Arizona
Correct Temp Reading (IR gun)
I wanted to make sure my temp gauge in my 67 427/390 AC car was correct....I have a recent rebuilt 390 hp (30 over) motor and has a Robert Shaw balanced T-Stat (180) and new Wells sending unit. My IR gun at the T-Stat housing and the gauge are right on. However, the upper radiator hose (near the T-Stat) is at least 20-25 degrees cooler, lower hose cooler yet, etc. I have been reading many posts on this and I want to make sure I am using my IR gun correctly to assure my gauge is accurate.
I see where John Z stated in a former post to shoot the upper rad hose near the T-Stat housing and that should be close to what your gauge is reading - well, it is off by 20-25 degrees. HOWEVER, the T-Stat housing itself and the gauge are right on. SO, what is the correct procedure to make sure the gauge is accurate?
I did not have a overheating issue until I put a new Holley Carb on and then it is running hot - so, my guess is jetting, etc. However, I do want to assure I know that the temp gauge is accurate, etc.
Thanks, Ron
I see where John Z stated in a former post to shoot the upper rad hose near the T-Stat housing and that should be close to what your gauge is reading - well, it is off by 20-25 degrees. HOWEVER, the T-Stat housing itself and the gauge are right on. SO, what is the correct procedure to make sure the gauge is accurate?
I did not have a overheating issue until I put a new Holley Carb on and then it is running hot - so, my guess is jetting, etc. However, I do want to assure I know that the temp gauge is accurate, etc.
Thanks, Ron
Race Director
Joined: Jun 2006
Posts: 17,901
Likes: 751
From: Inverness FL
St. Jude Donor '07
the thermostat housing and the temp sending unit are in close proximity to each other, therefore they should read the same.
one of the caveats i read about using an IR gun is to not use it on a shiny or reflective surface as that can give erratic readings so most say to 'shoot' the black hose, but i would think the hose would be a slightly lower temp.
Bill
one of the caveats i read about using an IR gun is to not use it on a shiny or reflective surface as that can give erratic readings so most say to 'shoot' the black hose, but i would think the hose would be a slightly lower temp.
Bill
Last edited by wmf62; May 4, 2013 at 06:57 PM.
