S10 over heating
Test the coolant for hydrocarbons, products like "Block Tester" at Napa can do that for you. That will let you know if it's a possible blown head gasket overheating coolant. Coolant may also be interrupted by trapped air, too.
So I chanced the radiator pump and thermostat all at once how do I confirm that there is no air in the system
You can't really confirm there is air in the system except by the fact it overheats after recent work on the system, so Google and follow the steps for bleeding air from the radiator, or 'burping' it. It might take more than one try to get all the air out.
I was having this issue with my S10 and it was fixed by flushing the entire system (after changing thermostat, thermostat housing, upper and lower hoses) I then replaced the coolant with Green coolant. The red coolant does more harm than good.
Looking for a Used S-10 in your area?
CarGurus has 1,205 nationwide S-10 listings starting at $1,600.
Search Chevrolet S-10 Questions
Chevrolet S-10 Experts
Related Models For Sale
Used Cars For Sale