My low coolant level warning light came on during urban driving
recently. I pulled into the nearest filling station and checked the
level in the expansion tank - OK. Thinking it must be the sensor I
ordered a new one. When it arrived I fitted it but the light stayed
on.
Then I checked the Jag-Lovers Forum archives. I should have done it
before!
I unplugged the sensor and shorted out the pins in the harness
connector - the light went out. I replugged the sensor and used a
magnet to close the reed switch. After a delay of about 20 sec the
light went out. (Perhaps there is a time delay on the sensor to
avoid spurious signals from sloshing coolant in the tank.)
I now believe my problem is the floating magnet in the tank. Is
there any way to get it out to check that it still floats? Note
that the 91 XJ40 expansion tank is different to the 88/89 tank and
there doesn’t seem to be a way to get at the float or lever as
suggested in some of the archive posts. I have poked blindly and
carefully with a smooth ended bent coat hanger without achieving
anything.
Is the dry pocket in which the sensor sits removable from the tank?
I am nervous about trying to dismantle things which are old and
made of plastic in case they have become brittle.
Phoney Dick 1991 XJ40 RHD 225K km–
PhoneyDick
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In reply to a message from PhoneyDick sent Thu 2 Nov 2006:
Which sensor did you order ?
The one that is actually on the tank can be taken out by
half twisting it. It is the only sensor in the tank. It has
no moving parts it is all solid state electronics. I
replaced mine once because it had a broken tab and would not
seat properly in the hole. I can send you a picture of the
sensor if you like just let me know.–
The original message included these comments:
My low coolant level warning light came on during urban driving
recently. I pulled into the nearest filling station and checked the
level in the expansion tank - OK. Thinking it must be the sensor I
ordered a new one. When it arrived I fitted it but the light stayed
on.
Then I checked the Jag-Lovers Forum archives. I should have done it
before!
I unplugged the sensor and shorted out the pins in the harness
connector - the light went out. I replugged the sensor and used a
magnet to close the reed switch. After a delay of about 20 sec the
light went out. (Perhaps there is a time delay on the sensor to
Visit the Jag Lovers homepage at http://www.jag-lovers.org for exciting services and resources including Photo Albums, Event Diary / Calendar, On Line Books and more !
In reply to a message from Macarina sent Sat 4 Nov 2006:
Hi Macarina
I ordered the DBC5546 sensor through my local Jaguar distributor.
It’s the same as the old one so I know it’s OK.
As you say the sensor fits into it’s pocket with a half twist
bayonet type retention.
However there is a magnetic float inside the tank which slides up
and down the outside of the sensor pocket. When this float falls to
the level of the reed switch the switch closes to iniate the fault
warning light on the dashboard. I think this float may be the cause
of my problem. I can’t find any information on it in the Service
Manual CD. Perhaps it’s integral with the tank and is not a
serviceable part.
I hoping that someone in the Forum has had a similar problem and
knows how to access the darned thing.
PhoneyDick 1991 XJ40 RHD 225K km–
The original message included these comments:
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