Nikasil issues were a problem in areas with high-sulfur fuel (usually obtained from cut-rate stations), particularly if thecar was used in short trips, not fully warmed enough and sulfuric acid residue pooled in the cylinders. Not much high-sulfur fuel is around in the US any more due to regulatory efforts. The dealer can do a "blow-by" test for you to see if your engine has been affected. Replacement engines are very rare in the US, more common in the UK. There will be a tag (yellow, as I recall) on the block if the engine was replaced by Jaguar. Much about this in the archives at jag-lovers.org.
Secondary timing chain tensioners on XJRs are much less an issue than on normally aspirated engines, due to the absence of variable valve timing, but can occur. Simple to check if the newer, metal-bodied tensioners have been put in by pulling a cam cover - see BRUTAL's recent post about this on this forum.
Water pumps on 1998 were a significant defective design, and must be replaced if not already done.
Other than that, remarkably bullet-proof, amazingly capable cars. My 1999 XJR has been utterly trouble-free since new, now with 115K miles (original everything, includine first-generation tensioners, with which I am comfortable, since it has had synthetic oil every 3K miles since new). Has taken me from Key West to Alaska, San Diego to New England, and most parts between - frequently at triple-digit speeds - with nary a problem.
________

1999 XJR

 

Wow! You must have been super lucky that's for sure to get such a rock solid car! After owning a 98 XJ8, i'd only opt for a late 03 in x308 series. There are bound to be tons of nick-nack replacements on an aging 10yr car. These things don't like to sit that's for sure.

Unfortunately you do have nikasil bores, andit can be aserious problem, especially if the car came from the south with cheap sulfuric south american gas. I think my 98 has lost some compression lately,Doesn't seem as chipper as before. Can I ask the price-tag on this XJR?

Where is the nearest dealership, i'd take it over for the $150 all around inspection to see if it's really juicing what the dealers says. My two cents, goodluck!

**EDIT** After driving the car yesterday after a while,I soon forget the extra money spent for restore taking it for a spin, burning the tires off. These cars are just a treat to drive, the only other car i've had morepeople compliment me on was when I drove my uncles 2005 bentley continental GT for two weeks.

 

Run Forest run....get a 2002 or above...knowing Jaguar themselves have taken to replace the Nikasil engines under warranty should tell you something...it's not a cheap gamble to play with a Nikasil engine...my 2 cents have gone through two engines this year..20 k in the hole..and still no nice dream as intended....just telling what happened to me...I would rather pay extra end get a 2004 if possible....anything but a Nikasil engine with no upgrades...

 

best part is check out x350 2004-05 most under $15k with like 45k milesthese days. Cheap!

 

To be honest I prefer the body style of the older ones. But I will consider the newer ones. Do these have the chain tensioner issues?

 

I also prefer the X308 body style. Pretty much all of the X308s need the secondary cam chain tensioners replaced as well as the waterpump and possibly the thermostat. But, these are actually not tough to do. My car has a Nikasil engine and I'm not worried about it. I've got 103K miles and no complaints. You can get a really good deal on these cars, and if you do the work yourself, you can have your cake and eat it too.

 

I have seen a couple 98 XJRs at really good prices. I am without a Jaguar at this moment, but hope to buy one soon. While the VDPs are really beautiful, it looks like an XJR may prove to be more durable. Is is true that the R has a stronger transmission? What else besides water pump and thermostat is a problem? And how difficult are the secondary tensioners to replace? don't want to hijack thread, but this is good info. I would be looking at 10 k miles per year min for a few years.
thank you, C