I recently replaced the radiator, water pump and themostat on our 1998 V70 with a 2.4 non turbo charged engine. The car starts and runs fine for the first 15 miles. Once you continue to drive past that, it overheats. If you slow down and keep the RPM below 1500, the temperature comes back to normal, but as soon as you resume normal highway speeds, it overheats. Any suggestions?

 

Heck, you've replaced everything that I know of. Are you sure the car temp is actually getting high? Could be a bad coolant temp sensor. It can be giving you a bad reading.

Did you change the water pump because it was overheating?