2002 XK8 convertible, 58k miles. Replaced cracked upper coolant tank, refilled, and no leaks, however the low coolant light comes on intermittently. After driving for 20 plus miles at highway speed then slowing to stop and go in town the low coolant light comes on. It remains on until resuming 65+ mph speeds for a few miles and it goes off again. This scenario repeats time and time again, and coolant level is not low.

The light will also come on an go off sometimes when the engine is cool driving stop and go around town.

Is it possible that an air pocket was trapped in the system when I refilled following the tank replacement? Any other ideas? I've read the other low coolant light posts and threads, but no solutions from those threads. new tank and cannot tell the float is sticking, coolant was 50/50, but I removed and added about a quart of straight antifreeze, so it should be well above 50/50.












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My 2002 XKR will get the low coolant warning if the coolant is only 1/2" below the neck, especially if the car is on an incline. Fill it up all the way to the cap, and I will bet the warning disappears permanently.

 

There may be a pocket of air trapped in the heater core, as there was in mine, and it was a pain to get out. I had to manually cycle the heat all the way up to HI when the thermostat opened, while driving through town to get it all out, several times. Also make sure your cap is on tight.

 

Check the coolant level in your expansion tank prior to start-up every morning for the next four or five days and add coolant as necessary. Not unusual at all for Jaguars to require this action after any work has been done to the cooling system. The trapped air will eventually work its way out....

 

The sensor is a notorious fail but check the harness connector is securely attached.

Provided the coolant is up to the filler neck in the Expansion Tank and stays that way through several checks, it's likely to be a false low alert.

Graham

 

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