2008 Silverado

[Sherri Conrad Bourque]

What is normal operating temp for 08 Silverado 1500 4.8L V8?

[Jsdirt]

If I remember right, it'll run between 195°F - 220°F, according to scan tool data.

 

The gauge in the instrument cluster should stay straight up in the middle at 210°.

[Sherri Conrad Bourque]

It got to 220 today. I just changed the overflow tank and no leaks are showing. I don't know what it could be. Had to add water to tank 

[CamGTP]

Could be a air pocket or the thermostat is sticking closed slightly. Either can raise the coolant temp above normal. The stock thermostat opening temp should start around 195º.

[JimCost2014]

21 minutes ago, Sherri Conrad Bourque said:

It got to 220 today. I just changed the overflow tank and no leaks are showing. I don't know what it could be. Had to add water to tank 

Welcome to the site.

 

Are you using a scan tool, or just going by the factory gauge to determine the 220 degrees. 

[Doug_Scott]

My 2010 4.8 runs a needle width to the left of centre when driving.  The only time it goes over that is when I am in heavy slow moving traffic. If you are seeing this temp when idling check to see if the cooling fans turn on. 

Why did you change the resevoir(technically it is not an overflow tank)?  You didn't enter your location in your profile so I have no idea if your winter temps go below 0 degrees C.  You will need to make sure there is antifreeze in the reservoir.  The owners manual should say where the needle should run.