Hi all.
I may find out this is more of a general question than specific to XJ8, but I'll start here...

Brief context: Several months ago, I made the "CD spindle donut" fix to my coolant reservoir, which had started incorrectly showing that my coolant was low, because the stock float no longer floated after the first time I flushed my coolant. It has been working fantastically, without fail for at least 4 months.

The other day, before making a couple-hour trip, I decided I should check my fluid levels. I removed the cap from the coolant reservoir. The coolant level was fine, though I noticed that the float was no longer floating. I put the cap back on without doing anything else. Then I checked the brake fluid. It looked fine, so I put the cap back on.

I then started my car and drove to work the next day. To my surprise, both the coolant AND brake fluid "low level" indicators were on. Haven't had a problem for months, and the two fluid levels that I checked were now showing low. Seems odd.

Anybody else experience this? I do know that, whenever I remove the coolant cap, it clearly is releasing a vacuum, because I can see and hear a big air bubble quickly going down the hose. Is it possible that the simple act of removing the cap caused my foam "helper" float to suddenly saturate and sink? And what about the brake fluid?

I did add just a little brake fluid (because it was nearly full anyway), and that satisfied the brake fluid indicator, but the coolant level indicator is on 80% of the time now.

Any thoughts?

 

Try nudging it with a plastic spoon -- gently -- and see if it rises up a bit. Sometimes crud gums up the shaft.

 

Thanks, Jim. Yeah, I already did that. It has been fine ever since I fixed it several months ago, and also the brake fluid level indicator was also lighting up, so I'm not so concerned with how to get the coolant level indicator to turn off as I am about whether there might be some other cause of fluid level indicators being triggered after removing and replacing the caps.