I am having the dreaded sporadic "low engine coolant" light issue, with the expansion tank always being full. I wanted to check the Degas bottle (the second overflow recovery tank) but am a little confused on the exact location of this Degss bottle. From JTIS it states " the degas bottle is located at the rear of the right hand front wheel arch". I take it from this that it is located on the passenger side (US), but in one diagram it is on the drivers side (left, US). I just want to locate this elusive degas bottle and check to be sure the hose is reaching the bottom and maybe also put some extra coolant in to be sure I do not get the low coolant light. I know it could be a bad sensor, but would like to check this degas bottle first. Any pictures or help on the location of this dam degas bottle would be appreciated!

 

It is in the left, US driver's side wheel arch. Remove the plastic wheel arch panel. The tube does not go all the way to the bottom but only about half way down.

Just overfill the cold pressure reservoir until the coolant overflows the secondary bottle and drips on the floor.

The problem is much more likely to be the sensor.

 

Before you replace the sensor, check that it has not simply worked loose under the recovery tank.

 

Ok, I took Test Point's advice and removed the left, US drivers side plastic wheel arch liner, and no Degas bottle!

So JTIS was right this time. It is behind the wheel arch liner on the right side (US passenger side) The JTIS description was correct but their diagrams are not. Anyway, my degas (where the heck did they get that name anyhow, I never heard of a Degas anything. Is it British??) bottle was bone dry, so I filled it about half way and so far the low engine coolant warning has not returned. If it does, on to checking the sensor. What happens if I just dosconnect the sensor? Will I get the warning message or not?

 

Sorry, but I did look it up in JTIS before responding and the drawing would certainly appear to indicate left side. As you say, the written description clearly state 'right side'.

The sensor I have personal experience with except on a XK8 not R. The ECM is looking for a closed circuit on the coolant sensor to indicate adequate coolant level. If you disconnect the sensor the 'low coolant' message should be on. With the connector jumped with a paper clip the message should be off.

Careful removing the connector, the sensor is fragile.

 

motorcarman accomplishes the same thing by filling the reservoir to brimming and then pushing down on the opening with a cupped palm to force the coolant into the only place it has to go ... the degas bottle. lather, rinse, repeat as necessary for the required volume.

 

Thanks PLUMS

I usually fill the coolant reservoir to the TOP and then place my hand over the cap opening. With my other hand I squeeze a radiator hose until I feel coolant running out to the Atmospheric Catchment Tank and repeat this until the bottle has some coolant to refill the reservoir when the coolant cools and 'sucks' it in. You can't overfill the Catchment Tank as the 'extra' will simply spill out on the ground.

bob gauff

 

Good thing you came along to add the forgotten part

There could have been a whole lotta' cuppin' with no meaningful result without the squeezin'.

 

Now that the weak lower radiator hose is replaced, when I refilled the Coolant Reservoir, I did not see any coolant overflow from the Atmospheric Catchment Tank onto the ground.

I used motorcarman's overfill technique and I can hear the coolant flowing into the Atmospheric Catchment Tank.