US version 2004 XJ8 46,000 miles. Only use Mobile One synthetic. When is sits for a period of time, like overnight, upon start up there is a very loud metalic sound that lasts just a few seconds. Sounds rotational but only lasts a few seconds then quiet again. My thought is starter or possibly timing chain hitting guides but it is only on starting the vehicle. Starting after it has been running it will not repeat. Only on a cold start. Where to start looking?

 

Being an X350 model, I suggest a quickie repost in that tech section.

I know some here with the 4ltr X308 engines get that at cold start, and hydraulic tappet noise has been discussed, but I am not sure of the end result.

 

Welcome to the forum Ktc4319,

I've moved your question from General Tech Help to X350 forum. Members here with the same model will be able to help.

Before looking for more complicated mechanical possibilities, are you using an OE oil filter or an aftermarket one with a non-return valve? If not, it could simply by the oil has drained out and it takes a few seconds to build up pressure after a cold start.

Please follow this link New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum to the New Member Area - Intro a MUST forum and post some info about yourself and your vehicle for all members to see. In return you'll get a proper welcome and some useful advice about posting to the forum.

Graham

 

Thanks for the info on the oil filter. This was my fathers car and he passed away so I just recently bought it from his wife. I know that the last time the oil was changed was the first time it was not serviced at the original Jaguar dealer so I will definitely look into whether the correct oil filter was used.

 

It could be the variable valve timing device. This uses the engine oil under pressure to vary the valve timing. There is an internal stopper pin that locks the unit until oil pressure has built up to 1.25 Bar, (or just over 18 psi) If this is sticking it could well not engage at engine shut down, (it's applied by spring pressure), hence the clatter at start up. After the engine has run a bit, things warm up, so the pin moves more easily.

This is just a suggested prognosis, BTW !

 

I concur with Fraser's prognosis. I've had the same issue for over three years now. It's annoying and sometimes embarrassing, but has not affected the operation of the engine. It's a huge endeavor to try and fix it, so I just left it.