Water Temp

[yank]

I just got my truck running, The temp gauge did not work so I replaced the sending unit and t-stat. The gauge says its running hot. It goes from cold to the red in less than 5 mins. The rad and hoses are hot so I think the water is circulating.
Is there a way to get the water temp using another thermometer?.
Like, Start it with the rad cap off and put a thermometer in the rad?

[Nium]

You got it. Start with engine cold and radiator cap off or with engine cold just after starting slowly and carefully remove cap before engine warms up. Place a high temp thermometer (candy or meat for instance) in the hole. Start it up and wait till the thermostat opens and take your reading and compare to dash thermometer. Now when I've done this in the past I haven't had a problem with coolant geisering out of the radiator but it could, so best done outside. Plus if you make sure to have the radiator opening higher then the head any air bubbles in the cooling system should migrate out the open radiator too.

Or get a thermometer gun and take temp readings with that.

[yank]

Do you know what temp it's supposed to read?

[Nium]

IIRC 180-200F Normal Operating Temp for a gasoline engine. 220F and up is hot. Going off memory so if that's wrong hopefully someone will chime in.