Temperature Gauge question

[RWT]

Just bought 2001 Conquest. Just wondering what temperature engine should run at. Gauge runs from 180-195. When stopped and put heat gun on thermostat housing it reads 140. Gauge says 180. Could it be a bad ground, sending unit or gauge? Anyone else have this problem?

[LarryW]

Just bought 2001 Conquest. Just wondering what temperature engine should run at. Gauge runs from 180-195. When stopped and put heat gun on thermostat housing it reads 140. Gauge says 180. Could it be a bad ground, sending unit or gauge? Anyone else have this problem?

Do you mean heat gun or temp gun?

[Mike]

I would think that was normal. The temperature gun on is measuring temperature on the outside of the system. The gauge is probably more accurate.

[LarryW]

I would think that was normal. The temperature gun on is measuring temperature on the outside of the system. The gauge is probably more accurate.

I agree, 100% normal for the gun to read lower the the actual gage!!!

[racerone3]

while i agree with Mike and Larry, i've seen a lot of gauges be off by ten to fifteen degrees. we were having trouble overheating engines in the race cars a few years back so we pulled all the water and oil temp gauges out and put the sending units in a pot of boiling water. all were in the same pot and we had a lot of different readings

[LarryW]

while i agree with Mike and Larry, i've seen a lot of gauges be off by ten to fifteen degrees. we were having trouble overheating engines in the race cars a few years back so we pulled all the water and oil temp gauges out and put the sending units in a pot of boiling water. all were in the same pot and we had a lot of different readings

I guess you could find the accurate one by seeing which one is 212 at boiling. Assuming standard conditions at sea level (at one atmosphere of pressure). lol, I sound smart dont I. Well... I copied and pasted.

[lewis]

Temp Gun

Have you checked the top of the radiator against the bottom of the radiator? Look at the differential temp. You will get a closer reading of what is going on that way. Have ran into this little item before when using a Temp gun. If the surface is shiny it will throw the reading off. Some Temp guns have a internal adjustment for this factor. We had charts for this.

Here is Websters explanation of the term: Just check the radiator

The emissivity of a material (usually written ε or e) is the ratio of energy radiated by a particular material to energy radiated by a black body at the same temperature. It is a measure of a material's ability to radiate absorbed energy. A true black body would have an \varepsilon=1 while any real object would have \varepsilon<1. Emissivity is a dimensionless quantity (does not have units).

In general, the duller and blacker a material is, the closer its emissivity is to 1. The more reflective a material is, the lower its emissivity. Highly polished silver has an emissivity of about 0.02.

[racerone3]

I guess you could find the accurate one by seeing which one is 212 at boiling. Assuming standard conditions at sea level (at one atmosphere of pressure). lol, I sound smart dont I. Well... I copied and pasted.

that's exactly what we did larry... we are at about 400 feet above sea level, so we went with 212. figured that was as close as we were going to get.