I'm looking to purchase an XK8 and remember seeing something about problems with the engines made prior to 2003? really not sure what to search for but evidently changes to the engines were made in the 2003 and later models ? any information appreciated, thanks

 

It may be that they changed from 4.0 to 4.2. The 4.0 had plastic-bodied chain tensioners which fail with time so need changing, whereas the 4.2 already has the new kind. (I don't know if this IS the thing for 2003. It is for S-Types LOL)

 

You'd be better posting this in the XK forum. However, it is well known the 4.0 litre V8 had two issues - (1) Nikasil bore linings that failed due to high sulphur levels in petrol, and (2) Upper timing chain tensioners breaking up due to being made of plastic, not metal, (Yeah, what idiot thought of this one !)
The 4.2 litre engine sorted all this out with steel cylinder liners and a different timing chain design which doesn't use tensioners (as I understand it).

The Nikasil problem was being sorted out in 1998, but I'm not sure of the VIN of change. So engines from about 2000 onwards are OK for the liners, but there is still the chain tensioner issue. Most advice is to replace the tensioners soon after purchase, unless proven the metal-bodied tensioners have been installed.

 

my mistake, thought I was in the XK forum.

 

I considered an x308 XJR, but ended up going with X350 (07) after test driving both

Doing research, you can find 4.0L engine fixes by VIN # on x308 site.