Low coolant level warning (spurious?)

[BOH]

Hi.

I occasionally get a low coolant level warning on start-up. The warning disappears within a few minutes and the reservoir is filled to the correct level and I'm never had to top it up.

The car is a '99 XJ8 4.0.

Any thoughts?

[NormanD]

It could be you have a small air pocket, as the water expands the level will go up.

You need to fill the top resevoir up to the top, the level indicator is very criticle. There is an expansion tank under the wing.

[Jaguar steve]

Might be just a poor electricial contact.
Removing and re fiting the plug on the sender unit on the tank will clean the contacts.

[SeanCW]

Have you lost coolant.

I had this problems, most noticeable downhll

Turned out to be a slight leak from a pipe near or connected to the reservoir.

SCW

[Tame Technician]

Could try this litle trick. We used back in 1998-2002 ish, customer complain intermittent low coolant on dash.

When engine is cold, or at least not red hot, take the cap off the coolant reservoir, have an assistant hold the engine revs up to say 4000rpm. The water level in the tank should drop, now fill it up right to the top and put the cap back on while the revs still held up. Works 90% of the time. I used to do so many, did it with watering can in one hand and throttle body in the other, hard on S/C as wont rev over half way. 4.0 N/A we sometimes did at 5000-6000rpm, get about an extra pint in them.

[BOH]

Thanks for the tips - will try them out and report back - isn't the internet a great thing!

Many thanks.