[x300] Mystery low coolant warning

Driving along happily today when the low coolant light went on in
the XJ8.
I let the engine cool down and checked the fluid level. It was OK!
Light has subsequently went out. Is it an air lock in the system?
If so how do I bleed it out using the black plug near the
thermostat?
I can find no reference to the bleeding procedure.
Thanks,–
Dan, 2000 XJ8, Bay Area CA
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

In reply to a message from rafferd sent Fri 21 Sep 2007:

I found the bleeding detail in JTIS. However, not under XJ but S
type!
In fact, there is very little under XJ for cooling. I suppose they
avoid duplication when components are shared. I am less than
impressed by JTIS, at laest this version I got on eBay.
This is probably the first time that the heater has been used all
summer. Perhaps an airlock ‘‘emerged’’. I will see hoew it goes
before doing anything.–
The original message included these comments:

Driving along happily today when the low coolant light went on in
the XJ8.
I let the engine cool down and checked the fluid level. It was OK!
Light has subsequently went out. Is it an air lock in the system?
If so how do I bleed it out using the black plug near the
thermostat?
I can find no reference to the bleeding procedure.


Dan, 2000 XJ8, Bay Area CA
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php

In reply to a message from rafferd sent Fri 21 Sep 2007:

sometimes high speed cornering can cause the the light to
come on. I don’t think the level has to drop much before the
light comes on.–
The original message included these comments:

Driving along happily today when the low coolant light went on in


XJ8 4.0 1998 - Ruislip
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php

In reply to a message from rafferd sent Fri 21 Sep 2007:

When I was at the Jaguar dealer I ‘lived to top-up reservoirs’. My
work area was close to the sevice drive and customers saw the low
coolant light and drove straight to the Jag shop. Just look at the
size of the reservoir and you’ll know why a few ounces low on
coolant triggers the ‘low coolant’ fault. The best way to top-up
the system and keep the fault from returning so soon is to fill the
reservoir completely to the top, cover the filler neck with your
hand and ‘compress’ the nearest radiator hose to force coolant into
the ‘atmospheric catchment tank’ (under the left headlamp assy). Do
this seveal times to fill the tank and when the engine cools it
will draw the required amount of coolant back into the reservoir
fron the catchment tank. bob–
The original message included these comments:

Driving along happily today when the low coolant light went on in
the XJ8.
I let the engine cool down and checked the fluid level. It was OK!
Light has subsequently went out. Is it an air lock in the system?


Owning and Repairing Jaguars Since the Early 70’s
Decatur, TX., United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php

In reply to a message from motorcarman sent Sat 22 Sep 2007:

Excellent tip!

Thank you, Bob.–
The original message included these comments:

coolant triggers the ‘low coolant’ fault. The best way to top-up
the system and keep the fault from returning so soon is to fill the
reservoir completely to the top, cover the filler neck with your
hand and ‘compress’ the nearest radiator hose to force coolant into
the ‘atmospheric catchment tank’ (under the left headlamp assy). Do
this seveal times to fill the tank and when the engine cools it
will draw the required amount of coolant back into the reservoir
fron the catchment tank. bob


Dan, 2000 XJ8, Bay Area CA
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php