I noticed that my 97 XK8 had a collapsed lower Radiator Hose when the Engine was cold. What does that mean never seen that before. Can somebody enlighten me on this. Cheers

 

Not an unusual situation. As the engine cools there is a vacuum produced that is designed to draw coolant from the overflow tank back to the reservoir. With an older, weaker hose the vacuum will collapse it too. Replace the hose and make sure the reservoir is correctly filled.

 

You might also want to check the Atmospheric Recovery Bottle (item 11) hidden in the depths of the front wing behind the wing liner:



This is where the excess coolant from the Expansion Tank (item 1) goes when the engine is up to temperature. The coolant is drawn back into the Expansion Tank as the engine cools.

Apart from the Atmospheric Recovery Bottle cap or pipes becoming detached, it can also get a build-up of slime or sediment in the bottom preventing it from functioning properly.

Graham

 

and the radiator cap which, as someone pointed out on another thread, is a much misunderstood item. Like everything Jaguar they have forsaken the agricultural for the intellectual - a reliable recipe for disaster.

 

Had the same issue last year. Started getting low coolant messages. Changed out the upper, lower radiators hoses. I did not have any records of the thermostat being changed, so I installed a new one and also replaced the plastic thermo tower with the cast unit. The base of the tower had spider cracking and also showed signs of a small leak. The bottom hose was a pain, had to remove the cooling fan assembly to get to the clamp. There are several threads on the tower removal which are very helpful. Jim

 

I had the same problem on my 98 xk8 I just replaced the expansion tank cap problem solved.

 

This is exactly right, totally normal. Your system is pressurized. Oooold hoses start collapsing, especially the big ones. Just replace them, it's cheap