I had the same problem with the expansion tank on my 2002 XK8. Looked like it was leaking from the sensor. It was, but only because that is where the tank decided to start leaking!

The rub is, I just got a new tank, in the Jaguar branded box, from partsgeek.com and installed it, and it is leaking under pressure too, right from the middle of the bottom of the tank! No visible cracks. Nothing! It's just seeping away through the brittle and porous plastic!!!!! How frustrating can this be! It's a $200+ item and it's bad out of the box!

I'm not dissing partsgeek.com here. I'm sure this "quality" product was bad from the factory and they just supplied it to me. Now I have to work through the return process. Maybe I'll have my car running again by Christmas, but then again, maybe not!

But what can you do but laugh!

 

Follow up on my experience with partsgeek.com. I sent a trouble ticket last night to partsgeek.com about the problem and woke up this morning to find that they are going to send me an RMA to send back the defective tank, and a link to re-order the tank with free overnight shipping! Also, I got a great email thanking me for trusting them with a re-order. That's pretty darned good service!

Just wanted to put that out there!

 

That's certainly a good omen. Keep us posted on how it turns out....

 

Update on expansion tank: Got the second tank from partsgeek.com and it is working great! I'm getting really good at replacing the tank now! Of course, once the tank stopped leaking something else had to go. Now I just need to stop a little weeping around the new aluminum thermostat housing. Nothing a little RTV won't fix.

Am I trying too hard to get this car to stop leaking. It is British and my almost 30 years of British car experience tells me that if it is not leaking, then you've run out of fluid!

Have a great Holidays everyone!

 

I just replaced the senso because the warning would come on intermittantly for no apparent reason. It took 2 min with only a screwdriver. I did check the float, and it was free clean and clear.

 

I just replaced the coolant reservoir on my 97 XK8, the bottom blew out. The sensor on the old one and the new tank from the dealer are glued in with sealant. I paid 290 USD at the dealer. Also one of the hose connections was plugged an obvious manufacturing defect I had to drill it out. Seems like I should get some money back but Im just glad to be driving the car again.


D. Meyer

 

The design changed some time back, Jaguar saying one overflow coming from the radiator was not needed. That is why your new tank had the plugged connection. Don't know why the sensor would be sealed into the tank.