2001 silhouette cooling fans

My 2001 when driving the temp needle will be at 1/4 way if I am in traffic it will go 3/4. I ideled it at home the cooling fans never kick in.

When ideling I cannot get heat but once I start moving I get heat.

Thanks for any help

When ideling I cannot get heat but once I start moving I get heat.
...potentially not a good sign...Is radiator filled to the top? Does it need topping with coolant/water often?

The radiator does need topped up maybe just over a cup of coolant each time

The fans won't come on until it gets around half way on the temp gauge, perhaps even a bit higher, ymwv but LMP is right, this could be bad news. The issue is the engine could have a manifold coolant leak which will behave just as you describe initially--particularly the part about poor heater performance.

You could have the coolant tested for contaminates--that would give you a better idea of what's going, but the general case with the coolant problems is the manifold gasket is leaking. :shakehead

is the manifold gasket hard to replace what will that lead to if not fixed

is the manifold gasket hard to replace what will that lead to if not fixed

It leads to a destroyed engine--and quickly. What happens is the cam shaft will wear on its journals because water runs down the engine block valley and lands right on the cam bearing journals.
If you wait too long then after the manifold gasket has been replaced, the cam shaft will seize up and snap, basically ruining the engine. This happened to three of these vans I've worked on and I replaced the engine with rebults. The rebuilder told me he has never seen a 3.4l chevy that didn't have bad cam journals.

As far as doing the manifold job, its not bad; takes a novice a weekend to perform. Read the older posts on this and the chevy venture forums for instructions and techniques.