This last weekend I was putting in some coolant to resolve the second "engine coolant low" warning light.


Upon inspection I notice that the upper radiator hose from the thermostat housing to the upper passenger side (U.S.) of the radiator was compressed, like it was under vacuum. Looking closer I saw that the hose had slipped about 1/4 inch. The clamp was a little loose, so I tightened it, and thinking that was odd, I added a second clamp as a back-up. I've had kitty for a year and have never taken that hose off.


ADVICE- Right now, today after reading this, go check your radiator hose clamps to ensure they are snug and that no hoses have slipped. I've read on the forum how some people have been driving down the freeway and have had their radiator hose come off. Now I see how...

 

I would suggest that your plastic radiator cross over pipe is failing and that the upper hose, and probably the lower hose needs replacing.

The plastic cross over pipe is famous for deterioration and leaking, as is the plastic thermostat housing and outlet pipe.

If you are going to open up your coolant system it would be a good idea to replace everything at once.

All hoses
Radiator cross over pipe
Thermostat housing with outlet pipe. Use the new aluminum version.
Thermostat
Water pump

Love this picture!




There are a lot of posts on cooling system failures this time of year probably due to the stress of very cold weather and very old plastic parts.

In a month the posts will be about failed fuel pumps due to storage over the winter.

 

I had this issue with two of my cars this winter. Both with new hoses and clamps. The huge temp swings here in Cincy they would leak for a moment. The times they did it the clamps were not tight enough. I am using the run of the mill screw clamps. Well one car is sold so good luck to them. The jag was the other one. I got them tight now with now leaks. I am thinking of getting the orig type for the jag.

 

The spring clamps are better when attaching to plastic parts. The worm screw type can be tightened to the plastic damage point especially on old plastic and have no give when faced with a 200+ degree temp change.

 

My thermostat housing is aluminum. Is there a company that makes after market/better than 15 year old jag plastic crossover pipes? Or are new plastic pipes from jaguar the only option?

 

My plastic housing lasted 97k on my 03. I don't think the housing is an issue other than we are used to cars that have metal ones that last the life of the car.

 

Plenty of the usual vendors have the crossover (distribution) pipe. The Jag part was only about $10 more, so I drove the 5 miles from my house and picked it up so I didn't have to wait.

This should be a metal part too IMHO. Bakelite will crack given the heat and stress.