A couple of days ago my tank was reading just over 25% full and I went

to fill it up which I did until the pump cut out.

On leaving the service station I realised that the gauge was only

reading 50%.

When I got home I left the ign on for maybe 20. mins. and the

gauge very slowly went up to 75%.

Next morning I turned the ign. on again and the gauge went up to 100% which

was the correct reading.

We know that senders can cause problems due to corrosion of the contacts but I suspect

that the above problem could be due to degredation of the float material causing it to

become less boyant. From pictures of the float online it appears to be a kind of plastic

foam.

Anyone come across this kind of problem?

 

Jaguar issues TSBs for all sorts of problems when they are discovered.
Read all you can about your car. There are hundreds of bulletins in the large file area.

bob

 

I replaced one of the sending units on my XJR. There are two. There is a on board diagnostic that can help confirm the problem. The sending units are mounted below the rear seats and underneath a large bung about 6 inches in diameter. Relatively simple to replace the sending units. I ran my gas down to about 1/4 tank when I did the repair, but it way not necessary. The sending units are about $90 each and I purchased a spare o ring for the bung to have one available for when I took it all apart.

RyeJag