I have a 2003 X350 4.2 V8 XJ.   It has done 99,000 miles.  When starting from cold, the engine emits a rattle, briefly.  Seems to be from the top of the engine, and lasts for only a second or two. It would appear to be caused by a shortage of oil, because having run for even a short time, on next start-up it is perfectly ok.  Any experiences of this?  Any suggestions for cure?

Hi John,

 

I take it you've checked the obvious - oil levels, oil consistency?

 

Regards,

Dave

Yes indeed;  actually the engine has been treated with the Forte engine flush, oil drained, re-filled with new oil with the Forte VVT special additive included.  But all to no avail - the problem remains.    Help please! 

Hi John,

 

I haven't a great deal of experience with these engines (I've had mine little over a year), since you're not getting a great deal of response here   have you googled the fault or tried "ask a mechanic", just type it in google.  You could always prefix it with Jaguar or XJ.

 

Good luck,

Dave

Think your diagnosis is correct, timing chain/tappets just pressurising on start up.  Doesn't sound like anything to worry about as long as rattle goes quickly.

These engines are sensitive to oil type and viscosity.  I only use a good quality fully synthetic 5W/30 oil that meets the latest jag spec.  I use GM 5W/30 (because I can get it cheap!) low ash oil, that exceeds all Jag, BMW, Merc specs. Made by Mobil I think.  Don't be tempted to us Halfords Comma oils etc.

Keep level at max on stick, dipped with oil hot after allowing no more than 3 minute drain down.  I always used to dip the oil on a morning but was told this is wrong for modern engines using low viscosity oils as they hold a good half litre up in the top of the engine.  Guy who told me this is jag/lotus trained engineer so think he'll be right.

He also said I was wasting my money using engine flush or any additives as these high spec oils do the job even with 15k mile change intervals.