Got surprised by a low coolant warning the other day. Took a look but it didn't seem like the over-flow tank was empty. Ended up putting in about ~1/2 gallon (or 2 liters for you others... ;-) and the warning seems to have gone away.

Had the system flushed and filled ~10K miles (16K km... :-) ago so I'm not terribly worried. Also put in a quart of oil (~1 litre, how's my math...) after 5k miles (forget the conversion, you can do it your self...) so that's not too bad either.

But I think that, from now on, every time I check my oil I'll have some coolant handy and top up the overflow tank just to see if the coolant use is stable.

Oh, 70K miles, and runs like a top
==================================================
Jaguar: Grace, Pace, and Space - Sir William Lyons
2015 JCNA National Slalom Champion Class M
Current: '08 Jaguar S-Type 4.2 "Satin Edition" (250.06 whp / 259.67 torque)

 

Hmm, I have never had to add coolant unless I had opened up the coolant system. A half gallon seems to be a lot. Check for coolant stains around water pump, DCCV, radiator or coolant reservoir.

 

The coolant header tank is notorious for splitting.
Keep an eye on it. If it has soak the bolts around the scuttle panel you need to remove to get at it overnight and ease them backwards and forwards so they do not break. I seem to remember small hands are an advantage to remove and replace the offending item.
Good luck,
Mike.

 

Well 2 ltrs , an expansion tank level gone, You have a leak!

I would keep a very good eye on the coolant water level and have a bottle of water in the car, in case.

I had a slow leak for a couple of months, which I tried to chase down.
About a header tank full a month.

Usual suspects.

The valley pipe, (the hose from water pump to throttle body.) The hose just went pop. The fibre reducer, was also fractured and weeping on this hose this was the mostly likely culprit.

water pump, the freeze plug was weeping?

DCCV. weeping from the valve body, and coolant stains.

All resolved when I had to replace the thermostat housing, due to internal fracture and overheating issues.

Doubt it is the radiator yet.

Since the leak is may be small, may be drop the under tray and see for staining.
You may pick the general area.

 

About a year after getting my S-Type I got the coolant flush done and ever after (its been 5+ years) I have to top off a little (drops below low mark) every 3-4 weeks depending upon how much I drive. No visible leaks nothing, got all hoses, reservoir, compressor, DCCV replaced over time God know where does the coolant goes but this is on my bi-weekly check list or I get Low Coolant light I keep driving.

Before the flush I never refilled and never got light.

I hope you don't run into the same issue but I was just sharing my experience.

 

You should have pink/red staining by now if you look closely.