Coolant level switch malfunction: 99 XJ8 VDP
#1
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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?
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?
#2
#3
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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.
#4
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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.
#5
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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.
#6
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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.
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!
#7
![Smile](https://www.jaguarforums.com/forum/images/icons/icon7.gif)
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.
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
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