Looks like a blockage or partial blockage and you need to investigate if there is

a constriction further along the hose in the engine.

There are plastic parts in that area which can disintegrate and cause blockagages.

Replace the hose shown.

NB I would avoid driving the Jag until the problem is solved because if you

lose a large amount of coolant while driving and don't stop immediately

you can ruin your engine.

The tank may be after market but it's made by MEYLE which is a good make

 

 

Get rid of those worm gear clamps, they are junk, high pressure fuel clamps hold better, but the spring ones are better yet. The spring clamps, keep constant, even pressure, on the many plastic coolant joints. Not too tight, or loose, but steady even pressure is what is needed, or they can collapse, causing all kinds of problems. There is a tool, that looks much like a pair of pliers, but with a reverse action, made to remove hoses from such joints. Had it for years, not expensive, & works great, Harbor has them as well, as other places. Amazed at just how many people have never seen them when they are pulled out and used, on their bikes & cars. Almost always then asked, where did you find those, & how much did they cost?