I own a 2010 XF 5.0L with 44,000 miles. I backed the car partially out of the garage and turned the car off. I know I should not have done that since I usually let the car idle until warm before I shut it off. Now the car will not start or crank, The car had sat for 5 days without being driven. I have lights, etc. I checked the voltage on the battery terminals, it read 12.14. I put a charger on the battery, but can only get it up to 12.27. I know I need 12.6 volts but the car will not crank.
I am considering replacing the battery tomorrow, but I am puzzled on how to remove the battery with the hold down bar. I bar is held down by a rod that does not have any type of head that could be turned to remove the hold down bar. Does anyone know how to remove this bar when removing the battery?
Do you think the battery needs replacing? I could call a tow truck to jump the car but if it cannot hold a charge I will have a dead battery as soon as I turn the car off.
Thanks for any suggestions.

 

The battery hold down rod should have a small 8 mm head on it, which you should be able to get a socket on and turn it.
But be warned, this rod is notorious for rusting solid underneath, where it screws into a thread in the bodywork. Jack the rear of the car up and you should be able to see about 1/2" of the end of the rod poking out.
Before you even start to think about loosening it or undoing it from above, give this bottom area of the rod a good long soaking in something like WD40. Otherwise there is a good chance you will snap the head off the rod.
Even then it's not guaranteed to come undone without breaking, so if you're not sure you can sort it out yourself best to take the car to a mechanic or a dealer.
If you can't see a 8 mm head on the rod then it's either been rounded off or broken off.
With the battery, it may or may not be fubar, but after 5 years and now being a bit dodgy it's probably due to be replaced.

 

Thank you for your comments. I know about the hold down screw as being difficult to remove. I didn't notice that it had a very small 8mm head on top. I will soak the screw top and bottom before removal.
After an all night recharge on a trickle charger the volts dropped from 12.27 to 11.88 for some unknown reason. When I try to start the car, all lights appear as normal on the dash, but the engine does not crank. Is there some type of fail safe that will not allow the car to start if the battery does not have sufficient voltage? If I try to jump start the car, will that be enough to start then car then?
Thanks again for any advice.

 

Sounds to me like a shorted cell in the battery. This is one reason a battery will not take a charge or jump from a good battery.

 

Is this the original battery?

 

I am the 2nd owner but I think it is the original Jaguar battery. I am going to jump the car tomorrow and purchase a new battery. Autozone has one for the XF, H8-DLG with 900 cca. I am hoping this cures the problem. I called the dealer today and he said that one of the cells had shorted out and to replace the battery. The dealer wanted $350 while Autozone is $160. Will let you know when I am back on the road. The car has been fantastic, faster than my '01 XKR, even the brakes are better, love the car.

 

Try to get an AGM battery as they are much more durable than standard batteries. I've enjoyed better reliability since switching all my vehicles over to them. No more worries about how long they sit or needing trickle chargers. My motorcycle regularly sits a month and fires no problem. They seem to recover better from discharge as well.

Interstate makes a replacement AGM for XF's. Don't remember the model number though.

 

Spend a few dollars more for AGM or Gell cell, they don't promote corrosion like lead acid, and will last waaay longer. Sears has the Die Hard gold Gel cell, I paid $220 for mine.

 

Problem solved! The AAA mechanic came out to jump start the car and while he was here he ended up installing the battery for me. The WD40 soak overnight worked on the hold down screw, came right out without a hitch. The mechanic even had a plug for the 2nd vent. We hooked everything up and I went to start the car, and the same no start. I turned everything off tried again, no start. Then I told the mechanic that the brake peddle seemed very hard to compress compared the previous starts. He suggest to press very hard on the brake pedal and then the car fired right up. I let it idle and we tested the battery again, it registered 14.4 volts. I was very pleased with the AAA service. Just remember to press very hard on the brake pedal after a dead battery.

 

Glad you solved your issue. The brake pedal problem you mention isn't directly related to the flat battery. Once you turn off the engine there is a little bit of vacuum left in the brake boost, so when you press the brake pedal with the engine off you get a bit of brake assist (making it easy to depress the brake pedal to restart the car).
But with the engine off, if you press and release the brake pedal 5 or 6 times firmly, the vacuum is used up and you are left to mechanically compress the braking system - making it extremely stiff to press.
My guess is that in your attempts to start the car you pressed the brake pedal many times, and so it became very stiff and hard to press. And of course the car will only start when you press the brake pedal - so you have to press it very very hard to register...

We have that issue on our Land Rover in the winter as my wife sometimes sits with her foot on the brake pedal for a while after the car is turned off, making it very hard to start the next morning.