With that many miles on it, plan on replacing the water pump and T-stat. Also check the condition of all hoses including those little (1/2", 5/8" or 3/4") heater hoses. If they're originals, replace them all with new. Before you dismantle anything, drain about 1-1/2 quarts of coolant. Don't do this with a hot engine. Buy and pour in a can/bottle of cooling system cleaner. This will get most, if not all, of the contaminants that inevitably build up in cooling systems. Follow the directions. After engine cools, drain the cooling system, flush thoroughly with clear water, then change out the hoses, water pump and T-stat. Now is a good time to do a second clear water flushing. Get as much junk out of the system that you possibly can. Dispose of properly. Empty plastic 1 gallon milk jugs work well for disposal purposes. Thoroughly clean all old gasket surfaces. A rag stuffed into the T-stat hole will help keep old scraped gasket materials out of the T-stat port. Just carefully pull the rag up out of the hole. A wet rag will help keep the gasket material stuck to the rag. Carefully blow out the water pump housing with low-pressure compressed air. Use the new gaskets and replace the T-stat and water pump. Use new clamps when replacing hoses. Get as close to recommended torque specs as you can. DO NOT OVERTIGHTEN. Also check for obstructions on the radiators. (Leaves, twigs, bugs, etc.). Clean as necessary. Use at least a 50/50 anti-freeze/coolant mix. Most vehicles can use up to a 60/40 mix. (60% anti-freeze/coolant). Don't forget to re-fill the coolant recovery bottle to the "Full when cold" level. Start 'er up. Check for leaks. Run it up to operating temperature. Shut 'er down. If coolant level in the plastic recovery bottle is low, add fluid to the "Full when hot" level. You should be good to go. Follow your vehicle manufacturer's recommendations for coolant/anti-freeze miles or time intervals for replacing coolant/anti-freeze. Don't let coolant stand in a puddle or leave it in an open container. Dogs and cats love that stuff but it's fatal to them.