@desertdude is right that v engine's w/p runs with timing chain
@Barry some radiators have a L neck and some might show that the direct under the cap lines are clear but the ones at the ends are choked a clear diagnosis is to open the plastic end and have a full through view....
Be careful firing the parts cannon, it can get expensive quick and the faulty part is usually found shooting your last bullet. Better to get a proper diagnosis.
Faulty radiator cap, you can turn the engine off when it’s hot and put your ear to it. You will hear hissing or maybe see staining around the outlet.
When the engine is cold look inside the radiator. It’s easy to see if it’s blocked up.
Faulty thermostat can be found by putting your hand on the radiator. From cold start, if the radiator warms evenly, the thermostat is stuck open. When the engine reaches temperature and the bottom of the radiator is hot but the top is cold, the thermostat is stuck shut.
Water pump is a bit more tricky to diagnose but sometimes they leak. Look for coolant staining around the bottom of the timing cover. A bad water pump can make the engine overheat at idle but when you rev the engine, it circulates the coolant and the temperature drops.
A bad cylinder head gasket can cause coolant and oil to mix. You will have coolant in oil or oil in coolant. Or the coolant can simply leak into the cylinder and go out the exhaust. Don’t worry, I’m sure you don’t have this.
Not always true. Some cars have externally mounted water pumps driven from an exterior belt. I learned the hard way. Just after I started driving my alternator belt broke and the warning light came on so I decided to just drive home and put a new belt on in the morning. Little did I know that belt was also driving the water pump. I was lucky and got away with just a cylinder head gasket. God bless the old days of cast iron heads.
Also worth changing the radiator cap first (low-cost fix), as I think treks mentioned before because if the cap is no longer holding certain pressure to open and close then this borderline heating is probable cause.
Then go with the thermostat change / checking
Then go with radiator check / cleaning / change
And last should be water pump change as it's inside the engine and most expensive repair.
or you could remove the cover of the radiator and inspect inside to see if the lines are choked or blocked as it a old radiator...water pump circulation can be observed after the THERMOSTAT has opened and you will see a swirl action at the cap...
P.S please don't try this yourself let a professional handle such things as really hot water is involved i really don't want you to burn yourself and end up in a hospital...