The good news is that XK8 4.2 engines fitted to cars from 2003 onwards are on the whole virtually bullet proof with all the problems associated with the earlier XK8 engines fitted from 1996 to 2002 having being resolved. For earlier XK8 owners like me, there are some serious issues but thankfully all can be resolved.
For cars built before 2003, the main problem areas are Nikasil engines, water pumps and last but not least timing chain tensioners and guides – potentially a costly problem if not checked and if required sorted out. The problem arose prior to 1996 as part of the XK8 parts design process relating to the V8 engines and the objective of reducing weight as much as possible using plastic component parts. This included the timing chain tensioners in particular the secondary chain tensioners.
In the earlier XK8 models, given the stress, heat and wear that this item has to endure sooner or later they can crack and begin to break up allowing chain contact with the metal inner support. This can then potentially lead to the chain slipping by a cog. A grinding nose on start up of a cold engine could be indicative that this has happened in which case the damage will have been done. Worst case scenario (chain slip or snap !) could be severe engine damage and costly engine repairs / engine replacement.
XK8 Upper Tensioner showing cracks and general wear to the plastic parts components.
To add further complications, there are also the lower timing chain tensioners and dampers which are far more inaccessible. These tend to be more reliable as the chain does not ride directly over the lower tensioner. If there is a pronounced rattling noise from the engine then these tensioners need to be replaced as well. Jaguar recognised the above problems and changed the design several times finally using a more conventional steel type of tensioner as fitted to the 4.2 XK8 engine.
High mileage cars may well of had their tensioners replaced but if not then it’s advised to have them checked and if required replaced with the later 4.2 litre type tensioners and guides.
There are two XK8 Parts kit options on the market just now but the key thing is that both should be genuine Jaguar XK8 parts to ensure the highest quality for these critical component parts .
The XK8 Parts kits are:
TOP TENSIONERS / CHAINS SERVICE KIT
Price from £140 to £175 + labour costs
TOP AND BOTTOM TENSIONERS / CHAINS SERVICE KIT
Price from £360 to £395 + labour costs
Additional parts may be required for the job as they can get damaged when removing the cam cover: These are:
Cam cover gasket: Outer Seal, Spark Plug Seals, bolt seals, variable cam sensor sealing ring etc)
It is possible for a reasonably competent amateur to do the job but specialist tools will be required as follows:
Camshaft position setting tool
Sprocket retaining tool
Suitable short Allen key socket
Quality socket set
To Order the latest 4th Generation V8 Timing Chain Parts CONTACT DAVE AT XK8 PARTS
XK8 and XKR Parts
