Hey everybody. I'm experiencing a major coolant loss on my 01 Jaguar XJ8. I checked the coolant tank this morning and it was completely empty, I could see the hose outlet at the bottom. I put in 5 bottles of water, went for a coffee run and kept getting low coolant messages but have never experienced anything relating to the temperature gauge. Upon arriving home I opened up the cap and it was only down about half an inch (don't know why it was telling me it was low). However, it is leaking from the rear engine a little to the passenger side. I can't see exactly where it is coming from, but it's definitely leaking. A drop every few seconds.

I was having the same issue with coolant loss yesterday, so I put it to the test. I filled it up and drove about an hour. No coolant messages, and upon arriving....I had my coolant, but it was still leaking slow. I don't get how I lost all my coolant overnight, but then other times I'm not. Any help would be appreciated.

 

Here is a video of the coolant leak as seen from the underside of the vehicle. It is dripping in multiple spots on the rear passenger side of the engine. I cannot see anything from the top end. Sorry for the poor video but I couldn't see what I was filming when recording it. Hope somebody can help! Thank you.

 

Your video looks like A/C condensation, the fluid is clear (unless your running straight water?) and mine drips in the same area, but not as profusely. Have you done a compression check, smelled the exhaust and run your finger around the tip of the exhaust? Your checking for moisture, perhaps an oily type residue (which antifreeze will leave) and smell for antifreeze. I do see what appears to be residue on the underside of the exhaust you were filming. Now it could be some road splash, but I am suspect of moisture from inside the pipe. Suspect only, since we can't touch it, so again, check the tailpipes. What about that floor pan?...it looked wet, was it?
If you can't do a compression check right now, check the plugs for abnormal burn (you should only have a lite white ash residue) and mark it down when you do a compression check. While there, check the valley hoses that run front to back under the manifold. Check the back of the block for run off also with a good flashlight. I know there's an octopus of lines there, but do your best.
How about your thermostat, when was it serviced last?

 

There's 2 main components you need to confirm 1. The header tank itself, these can develop hairline cracks around the join and only leak when hot, cool down, leak stops.
2. Coolant 'octopus' hose at the back of the engine on top of the trans tunnel. To get at it for a better look topside, remove the engine centre cover behind the throttle body and look down to check for leaks.