Hi, first time posting, so it might not work, we'll see.  Anyway, months ago had to change the expansion tank, (bleed pipe part broke off)

got a genuine Jaguar tank, correct coolant to fill back up, new rubber pipe (that took several attempts to get right) now I get the message

'coolant level low' when it's hot after running for awhile (30mins or so) but the tank is full, tried undoing the bleed screw on top of the tank

but just coolant comes out, car is petrol 3.0 V6, 53 plate, any help would be great, thanks, pete

hi Peter 

where does your temperature gauge sit when she's up to operational temp? 

regards

Steve

Hi Steve,

gauge always sits half way between hot and cold regardless of temp out side, summer or winter

regards

pete

Hi Pete

although you have tried to bleed it, my gut still tells me maybe an air pocket is in there somewhere? I presume the warning was not present with your other header tank? this maybe stretching it a little, but a battery that's low on charge / knackered! can cause all sorts of probs, certainly on the 'S' types, I presume that could also apply to 'XJ's hopefully one of the guys can chip in with more help than I can offer

I will be watching 

Regards

Steve

Hi Steve,

yes I'm thinking air lock somewhere as it doesn't come on straight away, as regards the battery, (which is the original one I think) you could be right,

I did read somewhere that a battery that's not in top nick can cause all sorts of strange things, and as I only use it mainly at weekends the battery sometimes

does seem to be a bit low, also I can't un-lock or lock with the key fob (which has new batteries in).  I'm not sure if there is a particular way to fill the system back

up, even though I only drained the bare minimum of coolant.  So if I have got an air lock what's the best way to shift it, I'm all ears!!!

Regards

pete

Hi Pete

many apologies for the delayed response, a potential client of mine has dropped an office move on me on Friday morning, with about 3 weeks to complete, so frantically trying to get stuff sorted my end!  

Anyhow, I'm absolutely staggered that if it is an original battery its still has enough Ummph! in it to turn her over, if so, then I would think, its time for a new one!! as a starter.

was the system drained completely when the new header tank was fitted? did you do it yourself or via a garage? if via a garage, then you need to take her back, if you did it yourself, I would suggest you take her to a garage, and have the coolant system drained and refilled. The remote locking could also be linked to a failing battery, no guarantees of course, but the omens seem to be pointing that way please remember, if you opt for a new battery, you most likely will need the radio code, and some of your optional settings will need to be re-programmed such as 1 touch up/down windows, drivers seat position (if you have memory fitted) and so on. I know nothing about XJ's, but the fact that your temp gauge is smack in the middle, seems to be a Good sign I would suggest.

please let us know what happens next

Regards

Steve

Hi Steve,

Yes I drained it myself, but only the bare minimum.  When I use the car regularly it turns over just fine, always starts first time, it's only if it's left for a short

while (week or two) it turns over a bit slower, but still starts first time.  I will get a new battery anyway, think 13 odd years is long enough in service.

Before I went away on Monday I had another look at it, took the tank cap off, put the heater control on max and fired it up, when it got hot the level

rose to the point it overflowed a bit, rev it up and the level would go down, squeezed the top hose a few times and some more would come out, repeated

this a few times, put the cap back on then went for a blast down the bypass, got back home and checked the level which was fine, so went away on our jollies,

did around 100 miles made up of motorways and towns before the 'low coolant fluid' came on, checked level when cold next day and it was still fine, used it all week,

came home and it has not come again at all, so maybe, just maybe the air lock has worked it's way out, we'll see, many thanks for all your input and if it raises its 

ugly little head again I'll let you know.