engine rattle on startup!

[painter]

Hi,
still looking for an XKR, have had an inspection carried out on a 64k 2006 (FSH) and apart from the sub frame (surface rust) there is a rattle on start up from the engine. Not what you would hope for but is this a common feature of the 4.2L or a latent problem such as timing chain/VVT? I know my XK8 (the engine has only done about 20k) does sound a little if facing up slope when started, but quiet on start up facing down slope!.
I guess the easiest thing to do is find one that doesn't rattle.

[mike020150]

I agree. Walk away unless it's super cheap. The noise could be something else other than a VVT but if you can't diagnose it accurately, bear in mind that VVT repair costs are not insignificant. Mike.

[painter]

Hello Mike,
well I have walked away, but with the XKR in my pocket. On the basis that the insurance is now a 12 month parts and labour warranty and if the rattle is not cured by a couple of oil flushes, and is considered by an Independent to be a serious problem that is ultimately likely to cause damage to the engine, then remedial work will be covered up to a max. of 3K. As the price was good, about 1k less than those I have seen with a similar history, It seems a good deal (also the sub frames are good, and about to be prepared and coated with Dinitrol). Will send some pics soon. Should arrive next week.

[XJ_Driver]

the insurance is now a 12 month parts and labour warranty and if the rattle is not cured by a couple of oil flushes, and is considered by an Independent to be a serious problem that is ultimately likely to cause damage to the engine, then remedial work will be covered up to a max. of 3K.

Just be mindful that if your insurance is a 'mechanical breakdown warranty' in order to make a claim you will first need to break down (ie. demonstrate a sudden mechanical failure). Age related wear and tear, particularly if already evident at time of purchase, is unlikely to be covered. Worth checking the small print

[painter]

thanks SJ,
I agree most warranties are built around an element snapping in two rather than not functioning correctly, but this is the dealers warranty worded specifically to cover the 'rattle' should it get worse or be found to endanger the engine within the 12 months, based on an independent report. Never 100% bulletproof but this outlet has good recommendations from several local sources so hopefully will cover.

[mike020150]

Let's be positive. If it's a good car, it will be a joy to drive and that's what owning an XK is all about. Happy motoring! Mike.

[painter]

Spent hours looking at reports of engine rattle on these cars prior to purchase, not so rare as I had imagined. As it is only on start from cold for approx. 2 seconds, nearly all seem to have overcome this by one of:- several oil flushes (Wynns engine flush), using 5W40 redline or Forte top end treatment. Seems to be more a case of allowing the oil to get to the VVT units/timing chain/hydraulic tappets (do these have hydraulic tappets?). So hopefully I haven't made a complete rollocks of a deal and can now at last enjoy an XKR. Also I believe the timing chain is self adjusting, and will rattle until such time as it clicks onto the next 'ratchet'. (???)

[mike020150]

If the noise is only present for 2 seconds after a cold start, it doesn't sound like there's a problem. For correct running, these engines are very dependent upon using the recommended grade of engine oil so beware of internet recommendations to use other grades. The operation of the cams and hence, the valve timing, is quite sophisticated. The tappets are not hydraulic. Each timing chain has a hydraulic tensioner with a ratchet to prevent noise on start up. Some, and only some, early 5 litres (possibly using the wrong oils/oil change periods?) have shown signs of chain stretch (usually a MIL lamp for emissions issues) at 50K/60K miles. Jaguar responded by changing the chain pitch and associated cam drive components. Only the last XKs had these components which are shared with the F-Type etc and to date, any such issues seem to have gone away on these later cars. Mike.

[painter]

well I've just had the belts changed, has to be a kit nowadays as Jag. don't sell just the belts - which is just as well because the tensioner had 'ceased', locked solid. Now replaced but hasn't cured the engine rattle, which although only on start up when cold for 2 seconds, it's not what you want to hear in the morning. Most likely VVT but will investigate and as this is a car I am keeping may have the top end opened up. Nevertheless a joy to drive, and although I enjoyed driving my old XK8 the new XKR is in a different class. posting.php?mode=reply&f=75&t=15809#
Notably noisy when foot down (in a good way) didn't realise the exhaust could be 'programmed' to be louder/quieter!

[mike020150]

Yes, the X150 definitely leans further towards sport and sportier handling than the X100 ever did. It's all in aid of even bigger smiles. Mike.

[painter]

as the rattle was increasing in duration and noise, I have had the top end opened up. Turned out to be VVT, and with both banks replaced the rattle is gone. Whilst doing the work the supercharger belt tensioner was found to be 'ceased', locked solid, so just as well to strip down and have the work done. Expensive yes, but most of this is covered by warranty and the engine at least should see me out. Did however find another 'dissimilar metal' corrosion problem, with one of the aluminium housings being attached by a steel bolt which had ceased in the housing and had to be cut out! (no separation) Surely Jaguar are aware of this problem.

[mike020150]

Hope that's all the problems out of the way and now you can get on with enjoying your new toy! Mike.

[painter]

I suppose predictably, there is now a question as to whether or not the 'rattle' is a warranty item as nothing has broken. If the VVT were to be left to deteriorate even further surely the end result would be chains slipping and eventually a serious engine failure? If they are losing oil pressure due to wear and tear (at 70k ??) there must be a point where they are no longer able to function correctly. What would be the consequences of that?