almost nonstart + rattling - The Jaguar XK8/XKR Forum

I just returned from two weeks in Norcal and about 1500 miles of both lazy and spirited driving through desert, mountains, and countryside. The car ran beautifully except for one major annoyance: several "almost" nonstarts in the morning. Each time it took 3 attempts to turn the engine enough to fire up. The last time I only got "clicks" on the first two attempts, then it cranked and fired up.

The battery is about 9 months old and reads 12.3V before starting; 14.2 when running (measured at the battery). The starter sounds like it has since I got the car, but I have never listened to any other so I don't know if that initial "RRRrrrrpp" is normal. The volt guage inside drops considerably (to around 9v) while cranking, then jumps quickly to the mid position. It never shows above that mid position.

Is it possible that my battery, even though voltage and other indications (windows work fine), is at near death?

OK...second issue. This is scary: Yesterday's startup also included the "death rattle". This is the first sound I have heard since I replaced the secondary CCT's and all the stuff last year. I can always make the VVT selenoids click by gently reving the engine at idle, but this was definitely different....and it definitely sounded like chain slap.

One key element that has been different on this trip is the high humidity and dampness each morning (remember, my car sits in the desert in <10-15% humidity). Yesterday, I was in Gardnerville, NV and the AM temp was probably about 30 degrees. The car was uncovered in a motel parking lot, and had icy frost all over it.

Is there any possibility the cold and damp could affect the starting AND chain tension?