I am in the process of getting the notorious front outlet fused pipe (AJ89664) as well as the engine coolant outlet flange (AJ814007) replaced. Everything is original and my car has 14,000 miles. My water pump was replaced over a year ago with the latest updated version. I know that any and all the plastic cooling hoses/parts are vulnerable to failure over time. My local Jaguar service manager (who owns an older XJR) suggested to me... if it were him.... he would change as many plastic parts that were feasible at the same time. He mentioned that the order of failure for our cars is 1) Water pump 2) front crossover pipe 3) rear coolant outlet flange and 4) thermostat housing. Of course any of the very small thin plastic lines are vulnerable when taking things apart. Has anyone replaced most of the plastic cooling parts for the 5.0 engine and if so...approximately what would be the cost for such an undertaking...Does anyone have a diagram of all the plastic hoses/parts? I would be going with an independent first, and as a last resort... the dealership. I would imagine, that once the manifold was off, a big part of the cost would be parts. Of course, if I'm going to such an expense, I want the job done right....that is why I had the dealership option, although it would probably be prohibitive.. Thanks all.

 

I also replaced all of the hoses and radiator, mostly out of need, even on a 5 year old vehicle, all of the JLR rubbish parts were springing leaks all over.

 

Had all on my hoses, welded plastic parts, valley hose, and thermostat replaced by the dealer when it was in for supercharger isolator repair under warranty 2 years ago. I paid for the preventative maintenance replacement of hoses etc. Was a good time to do while the supercharger was removed.
However, the tech messed up and bent the supercharger actuator rod and never told ne. I noticed it bent under close inspection and went back. The dealership then replaced the complete supercharger with a new one. Be careful who works on your car. Take lits of prework pictures and check on the work.