Well I had a low coolant warning yesterday. Maybe 30 seconds. Checked it out when I got home and coolant was about 2- 3” below top of reservoir. I’ll keep a eye on it

but I noticed a fitting with no hose. Am I missing something?




2003 XK8

 

No, you are not missing anything. Your coolant reservoir cap may have failed. When they fail, coolant can get transferred from the reservoir to the overflow tank in the fender well as designed, but coolant often cannot get transferred back from the overflow tank to the reservoir when needed. These mostly plastic caps typically last only two or three years at best. My wife's 2006 XK8 is currently on its fourth cap....

 

Thanks Jon89

are you saying that fitting with no hose is the overflow pipe? Is there a way to test the cap or just buy a new one?

Randy

 

No, that connection should be blank for your model year (i.e. plugged, no coolant will go through it). The design changed over the years, but the external connection remained...

 

And yes, buy a new cap.

 

Hopefully it is just the cap, which is an easy fix.
Plan to check the rest of your coolant and heating system.
If you smell a sweet smell, like maple syrup, that's coolant.

I got the low coolant warning as my water pump started to slowly fail and leak.
I'm a big fan of pressure testing to find coolant leaks and that made the source of my coolant leak obvious.

 

I always keep a couple 20 oz water bottles filled with coolant in the trunk to make the light go away. Never thought about the cap and overflow being the problem. Thanks!

 

The coolant level sensors are known for failing so if you get intermittent low level indications, that is something to consider.