Why did you replace the water pump and were you losing coolant before changing it?

 

When was the thermostat, with housing last replaced?
They wont last much longer than a hundred thousand miles.
Speaking form my experience as well as many others from what i have read.

 

I currently have a coolant leak on my thermostat housing at the base of one of the pipes that feed the EGR/Throttle body. Check the whole housing which is made entirely of plastic as it tends to break or crack

I'm not sure if your car is a supercharged version. If you do then I believe there is a hose in the valley of the V of the engine that is prone to leaking. If that is leaking slowly then you may not see any visible signs of coolant leak. If it's leaking badly then you may see coolant leaking down the back of the engine.

My leak is as shown in the image below:


Thermostat housing coolant leak.

 

Exactly where my 04 was leaking coolant from.

 

 

 

rf69 - Is your car supercharged or NA ?

 

It is not the Xj8 supercharged it is just the XJ8 a 2004 . but I would have to take a look again to the thermostat assembly since it is mostly made of plastic to see if any leaks I think it is still the one from factory.

 

Good information I would have to take a look again to the thermostat assembly since it is mostly made of plastic to see if any leaks I think it is still the one from factory.

 

WAY PAST TIME!!!!!!!!!
If it's at 226,000+ miles on the original.
I'm amazed to say the least.

 

water pump was bad, leaking

 

That is my thought, i willl take a look to it and see if I find something

 

Took look under the jag to see if I could trace the leak and all I saw was a trace coming down from the driver side of the engine by to the catalytic converter, I took a look also taking apart the throttle body and did not see much. it appears to be the base of the thermostat assembly but it is hard to say, there is a hose that connects to the throttle body that goes further in the top of the engine, did not see much further. I added more coolant fluid and no leaks as long as I do not turn the engine on.
At this point I would have to take it to the mechanic tomorrow.
You can see how it is dripping after I started the car

 

Be brave you can do it if you try.
The rest of us do, saves you a lot of cash..

 

Had a mystery leak, it was the coolant tank overflow hose the bends under the air inlet on the engine, it was dripping onto the engine and burning off before it ever hit the ground. The hose was like $30.00 and ten minutes to repaint. Worth pulling the plastic cover off it and searching for wet spots with a flashlight.

 

That could be a 'Valley Hose' leak? Our N/A cars also have a cooling hose that goes in under the Inlet Manifold, does a 180 under there and comes back out and up to the Throttle Body. When it leaks, the coolant runs down the 'valley' to the back of the engine and drops out behind one of the front wheels (mine was the drivers side LHD vehicle).
See Michael Hamilton's post: https://www.jaguarforums.com/forum/x...on-s-c-149873/

Perhaps you should remove your underbody tray so that you can more easily isolate exactly where your leak is coming from?

 

Probably thermostat assembly and/or valley hose.
Congratulations for your 226 kmiles car!

 

That's not a leak, its a flood.
Sorry to hear about your issues.
But 226,000 miles before hand is pretty good.
Better get busy fixing, or dig deep into your wallet!!!!!!!!!!!!!!!

 

Mine only leaks from the thermostat housing when the engine is running and when under pressure. When the car is cold or left to sit then there is no leak. And when it does leak it runs down the side and front of the engine.

Yours is quite a major leak if the fluid is coming out that much.