what is the typical engine temperature for a 2008 GMC Silverado Pickup Truck

What is your question?

cooling fan does not come on until temperature gauge hits 240 degrees, or if I turn AC on it will cool the running temperature to 210/220 Have had radiator replaced and dealer says this is normal.

What makes this problem better or worse?

better when turn AC on.

How long has your 2008 Chevrolet Silverado 1500 had this problem?

4 months since I bought it