I purchased my car about 7 months ago. So far, so good.
When I first purchased, I checked the coolant level, and it was at the lower end of the tank. In my self defense, I DID NOTHING. I never added coolant.
However, I have always smelled a feint odor of coolant after parking in my garage. A regular check of coolant level, showed that the coolant level did NOT drop in the past 7 months of driving (5k miles)

A few days ago, I decided to top off the coolant level with some water. It took about 2 cups to get just below the neck.
Since topping off, I no longer smell coolant after parking in my garage.

Could a lower than normal level cause fumes to expel into the expansion tank instead of coolant and possibly give off the odor? I smell nothing.

 

The cooling system in your Jag is a closed system. If you are adding coolant or water you are losing coolant somewhere.

Keep a careful eye on the level, nothing worse than overheating a Jaguar.

Mine was leaking in 4 places when I bought it. And the idiot PO had used "stop leak" What a PIA that was to clean up.

 

There is an atmospheric pressure overflow tank in the right front wheel well.

When the coolant expands as it warms up, it will push past the pressure cap and end up in that tank. The idea is that when the fluid cools, it will siphon back to the pressure tank.

If you've ever noticed a slight vacuum or gurgling sound when you take the pressure cap off, this is why, it's the residual fluid in the tube draining into the tank.

I get a faint coolant smell now and then too, but never seem to lose any. Maybe give a sniff around that area and see if that's where it's coming from.

It's possible you've got a small crack in that tank or could be topping it off got enough liquid into that tank that it covers the siphon tube and that's why the smell went away.

 

Get a coolant system coolant pressure test kit from a local parts store. Some still have them to loan out and some have the cap for the jag. That is the best way to find the leak when it is not visible when hot and prob just burning off and you can't see it.
Do the test when the car is cold. If you have smelled coolant coming off the motor, there is a problem, these don't fix them selves.

 

+1 on doing a coolant system pressure test. I would venture a guess that you have a bad coolant tank cap. The coolant as it expands will go to the overflow tank but want siphon back if the cap is bad.
If the pressure test show no leaks then I would get a new cap.

 

A bad reservoir cap may indeed be the culprit. A new cap fixed a similar problem on my wife's 2006 XK8 a couple of years ago....

 

You may also want to fix the level sensor, that much missing should have triggered a low level yellow caution. There maybe several reason why it doesn't from stuck float (internal) to the plug being jumper-ed. This will then give you confidence that if it goes down you will know it.

 

If you think it is a cap and or a level sensor in that tiny resivor, just replace it all, it is easy!

 

+ 1 on the cap and sensor. Also the expansion tank on my wife's xkr had a fine crack underneath that would only occur when it got hot. Did not show up on pressure test when cold. Look/feel for wet area under tank. The smell is the coolant dropping onto the header and burning off. It fooled me for a couple of weeks. The caps seem to be a weak link. Get a couple of spares they are not expensive.

Mike K.

 

Is there any dried up rad fluid around the seems of the small black tank? Look for that also. That means it is leaking off.

 

You may also see dried coolant residue on the ends of one or more of your rubber coolant hoses. In September 2015 I replaced the leaking factory upper radiator hose assembly in my 2005 S-Type 3.0 with a relatively inexpensive one from the well-known hose supplier known as Uro. It began leaking a few drops of coolant from one of its seams within a week after I installed it. I removed it and sent it back to the company I purchased it from, and they sent me a replacement. Now, that replacement is losing tiny amounts of coolant at a couple of the hose ends on the assembly. Not enough coolant loss to drip, but enough to seep through the hose end and then dry out due to the engine bay heat....

Lesson learned - I should have ponied up another $25 and sourced my replacement hose from Welsh Enterprises (which I will be doing eventually). It's not the money so much as it is having to do this very unpleasant job for a third time. I guarantee you I won't be ordering any more Uro hoses....