I developed a Big leak which seems to come from back of the engine. It did overheat rather quickly and now does not hold coolant
Is there a plug? at the back of teh engine that can give way or??

 

There's a coolant hose that runs underneath the intake manifold within the "V" valley of the engine. When it ruptures, the coolant spills into the valley and spills out the back.

The hose itself is only around $15 but a garage will charge you around $1000 for labor because the intake manifold and a bunch of other bits need to be removed. If you're handy, you can do it yourself over a weekend if you take your time and follow the steps. Do a search for valley hose and you'll get more info.

 

Oh no.... I thought I was safe from this malady with a non supercharged car. You mean the NA cars like mine ('04 VDP) have the dreaded valley hose too?

 

Intake manifold is not ALL that bad a job. Replace all the gaskets while things are apart, all ten of them, as a precaution, b4 reassembly of parts.

 

Yup

 

GULP mine too?

 

Deleted - misread

 

It does seem that they are a common issue with the XJR's. I assume it's because of the additional heat from the supercharger and piping etc. It doesn't seem to be common with NA jags.
FWIW, it would much easier to replace on a NA V8, the intake is right there.

 

Easier to be sure, but still a pain in the but.