In short - ever since I flushed the radiator, my "engine coolant low" indicator has been on more than it's been off. My coolant level in the expansion tank is fine.

Yesterday, I thought I would take a stab at fixing it. Here's what I did:

- siphoned everything out of the expansion tank
- found float/donut and confirmed that it was movable with a flat popsicle stick.
- pulled sensor out of bottom of tank.

At this point, I noted that the plastic tube that fits over the reed switch was broken, though I could slide it back over. I don't know if I broke it while pulling it out or if it was already broken.

Then, I attached a meter on continuity to the prongs of the sensor and confirmed that when I put a magnet near the switch, it closed the circuit.

I put everything back together and filled it back up. I noticed that the donut didn't rise with the liquid. My thought was that maybe it won't float until it's under pressure, though I did confirm that the "coolant low" light turns off if I raised the float.

So, what am I missing? What is SUPPOSED TO make the donut float? Is it possible that the switch, because of the broken tube, is not centered and therefore the magnet isn't triggering it unless the donut is turned to a particular position? Do I have a pressure problem?

Again - the switch works, and when I manually raise the donut, the warning light turns off.

Ideas?

 

The 'donut' gets stuck on the internal float tube because of crud in the coolant. Remove the overflow tank and fill it with coolant system cleaner overnight. That will, most likely, restore the floats ability to ride up and down on the tube.

 

Test Point, before attempting yesterday, I read several forum topics that mentioned crud preventing it from floating, so, while it moved up and down with ease even the first time I tried, I did clean around the inside of the donut and the outside of the post with a thin flat rod. There appears to be no resistance when manually sliding it up the post. Should it float up with the presence of liquid, or should it only float up after pressure has built (cap is on, engine is running)?

Could it be anything else? It's of course hard to see the "donut" when there is coolant present, but I'll check again if it's just sitting at the bottom or if it's floating up.

 

If sediment is not the problem, your float might be waterlogged and a new tank is the answer. See https://www.jaguarforums.com/forum/x...esolved-80074/ for an extended discussion on the subject.

 

Hey, sorry it took me this long to respond/update. I went off and read the thread that you linked. It basically concludes with a couple of successful stories about taking a foam donut that comes in blank CD/DVD spools, cutting a slit, and then popping it onto the post underneath the expansion tank float in order to give it just enough additional lift. Figured I didn't have anything to lose by trying it, and it is waaaaay less expensive than replacing the whole expansion tank. So I tried it about 4 days ago, and it's been working fine. I'm happy for now - and of course I'll still keep an eye on the coolant level as well, just in case.

 

Just make sure it is reliable. It is really important on these cars that the low coolant warning works.

If a hose were to burst and you were to loose all of your coolant, this could be your ONLY warning, since the fluid would be below the coolant temperature sensor and unable to indicate overheating.

A new tank is a bargain compared to an engine replacement!

 

This is my first time responding on this site. My mechanic said that I was done almost a gallon of coolant. Then the light would not go off and he couldn't figure out what to do. I am going to attempt the "foam donut" myself because I am a woman on a mission!

I just recently took out my clock and car radio for local repair. Nightmare of an idea! There was nothing wrong with my audio on both radio and CD player but I wanted to preserve the sexy cat's dignity even though she was raped about two Memorial holidays by someone driving into a private parking lot by stealing her hood ornament. She is a 1997 Vanden Plas with less than 50,000 miles. I ended up with paying $239 for an LCD digital replacement and had to purchase a radio for an LCD from a junk yard. This was no easy task to reinstall and both jobs are questionable to me. This all happened today so the report can change any time.

Thank you Jaguar lovers for this website.

Christina Miller

 

Did your mechanic find where the coolant went? It's leaking somewhere for sure..

I'd suggest starting another thread to discuss any problems you're having, because tacking on to the end of an existing thread often gets lost in all the new posts on this site.

Welcome!

 

Welcome to the forum Christina. +1 on Robs' advice. When you have time please visit the new member area and introduce yourself.