1998 XK 4.0 - Noisy start up
Discussion
Is it a fast clattery rattle, that sounds rather like a pushbike chain contacting the chainguard? If so, and it goes off a bit as the engine warms then chances are that's the exhaust cam timing chain dragging on somthing it shouldn't be. I'd suggest you have both the secondary timing chain tensioners checked as soon as possible as one may be about to let go. These are a weak spot in the V8 and should be changed to the mk 3 metal bodied type even if they look OK. I'm not suggesting that's the problem but at least checking them or better still changing them brings some peace of mind.
If not it could be one of the VVC units getting a bit noisy as they can do, the accessory drive belt creaking or squealing - a puff of talcum powder on the belt will soon prove that or poor quality oil making the valve gear a bit tappy until the running clearances close up as the engine warms. You will hear any V8 making a quiet snicking noise at idle, that's just the injectors and is normal.
If not it could be one of the VVC units getting a bit noisy as they can do, the accessory drive belt creaking or squealing - a puff of talcum powder on the belt will soon prove that or poor quality oil making the valve gear a bit tappy until the running clearances close up as the engine warms. You will hear any V8 making a quiet snicking noise at idle, that's just the injectors and is normal.
Many thanks all and now having done some research on the net it wood seem that this is quite common and is often down to the VVT units on the cam ends.
One piece of good luck is that owing to the early age of my car, the VVT units are located externally and therefore are somewhat easier to change so I am hoping it is a simple issue of unbolting and bolting the new units but please let me know if this is not the case as I am very much still learning on this car.
Would any of you recommend changing to a thicker oil - its only 76000 miles but it had been standing for a long time by the previous owner and this does same to be a common cause feature.
Kind regards
One piece of good luck is that owing to the early age of my car, the VVT units are located externally and therefore are somewhat easier to change so I am hoping it is a simple issue of unbolting and bolting the new units but please let me know if this is not the case as I am very much still learning on this car.
Would any of you recommend changing to a thicker oil - its only 76000 miles but it had been standing for a long time by the previous owner and this does same to be a common cause feature.
Kind regards
I'd stick with 5W/30 or 5W/40.
Use a genuine synthetic oil - not some of the hydrocracked mineral oil that's allowed to be labelled and sold as a synthetic. Somthing like Fusch Titan GT1 will do and change it every 7-8k if you want to avoid long term chronic wear and degeneration of gaskets, seals and internal plastic components. Synthetic oil will improve fuel consumption too and more than pays for the extra cost of a sumpfull in fuel savings.
Andy at Opie Oils will talk to you all day if you want to know more about oil selection.
Use a genuine synthetic oil - not some of the hydrocracked mineral oil that's allowed to be labelled and sold as a synthetic. Somthing like Fusch Titan GT1 will do and change it every 7-8k if you want to avoid long term chronic wear and degeneration of gaskets, seals and internal plastic components. Synthetic oil will improve fuel consumption too and more than pays for the extra cost of a sumpfull in fuel savings.
Andy at Opie Oils will talk to you all day if you want to know more about oil selection.
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