Don't mind my paranoia..

Started the car in my driveway. Let it run for about 15 minutes while I wiped the car down.
Opened the hood for a routine visual, and decided to squeeze the radiator hose.
Car was hot and idling.
Hose was not firm.
Was it supposed to be? Just curious.

Take a look:

https://www.youtube.com/watch?v=ifYq...ature=youtu.be

 

THE HOSE SHOULD BE FIRM. It's partially collapsed in the video. You probably have air trapped in the system. The upper hose returns coolant to the radiator so low coolant will collapse this hose. You should "burp" bleed the system to confirm.

 

Can we discuss ^^^ This?

After driving for about another half hour, I rechecked and it was firm.

 

I just did a Google search for "how to bleed an XK8 cooling system? " there's at least 5 posts on how to do this. Disregard the S and X cars.

 

Also note a symptom of age is that these hoses break down, and become soft when hot. If they get too soft they will collapse and restrict water flow.

Have a trusted mech, give it a squeeze and let you know how much life is left.

 

While I agree about old hoses failing, what I see is a low coolant problem.