01 Olds Silhouette Van. Constantly overheating. We have replaced radiator, thermostat, radiator cap, has had a flush. Still overheats. Forces coolant into the reservoir and overheats in the process. Getting g really tired of sinking money into.this thing.
they found overheating to be connected to blown headgasket[s]
IMO it’s quite possible the intake gaskets are blown, causing all these symptoms
For a third possibility, are your radiator fans running when the car is overheating? Diagnosis is better than parts replacement. When it first started, you or your mechanic should have checked to see if the fans are running, looked for leaks, done a pressure test if the fans are ok and no leaks found and if that didn’t reveal anything, done a chemical check for exhaust gas in the coolant.