Where to point infrared temp gun?

[doogievlg]

I noticed a small puddle of antifreeze under my Dart after driving it for about fifteen minutes. My gauge never went above halfway so I am going to use a temp gun to see if the gauge is accurate. Should I point the gun at the intake near the sending unit or should I shoot for the hoses going to and from the radiator?

 

[Bad Sport]

Should I point the gun at the intake near the sending unit

That's where I would check, the rubber hoses aren't going to give a real good read.

 

[Treblig]

I noticed a small puddle of antifreeze under my Dart after driving it for about fifteen minutes. My gauge never went above halfway so I am going to use a temp gun to see if the gauge is accurate. Should I point the gun at the intake near the sending unit or should I shoot for the hoses going to and from the radiator?

If your gauge never went above halfway it probably never got hot but you never know?? I'd look for a loose hose clamp first or follow the trail of the fluid which will lead you to the leak?? When I had doubts about my temp gauge I bought a "cheapy" gauge from the parts store and hooked it up. In the end I used my laser gauge at the upper return hose metal housing (not on the rubber hose). Checking at the sending unit will give you an idea of what the temp is at the unit but the important reading is where the water leaves the engine.

Treblig

 

[doogievlg]

Drove it for about ten minutes and pulled back into the garage and let it idle for ten more minutes. Highest reeding I got was 190 on the block. Intske was 180. It piled fluid out at first but it quickly stopped. I'm thinking the radiator could have been too full.

 

[nm9stheham]

Do you have a radiator overflow container on that car? If not, you're gonna have to run the coolant about 1" to 1-1/2" below the fill on the rad, or it will always be puking some coolant.

 

[doogievlg]

Do you have a radiator overflow container on that car? If not, you're gonna have to run the coolant about 1" to 1-1/2" below the fill on the rad, or it will always be puking some coolant.

This is what I have learned. I am going to be getting an over flow.

 

[AJ/FormS]

Getting back to the IR gun;
Just keep looking for the hottest spot. Usually just below the thermostat, or on the housing, but not necessarily so.

 

[Killer6]

That's where I would check, the rubber hoses aren't going to give a real good read.

Yeah, ^^^^^^this right here is fact, different materials and finishes have different emissivity, in other words........they don't "show" their heat to an IR sensor
the same. I have one of the first Raytek guns w/a bunch of bells & whistles......one very useful one is the ability to adj. for these differing materials/surfaces.
On a typical engine, a relatively dull iron surface give the closest "real" numbers, between rubber hoses, plastic rad tanks, & clean/machined alu-minimum
surfaces, You can get a 30deg spread in numbers from a fully warmed up unit!

 

[nm9stheham]

If the surface emissivity is in question, apply some flat black paint. Not too great for appearances though...