New to XK forum

(Stephen J. Niznik) #1

Good day gents and ladies. I am new here but active for years on the XJ-S, XJ6, XJ40, E-Type, and XK150 sites for years.
I just found a splendid 2000 XK8 Coupe that has been garage kept and has been fairly taken care of. It has 90,700 miles on it and I’m wondering what if anything I should be most aware of for maintenance and/or repair. Shortly after I take possession of it I will be doing things like brake fluid, belts, hoses, other fluid and filters. The car does have a new transmission in it.

(Grahame Loader) #2

Have a jag mechanic check if the timing chain guides and tensioner have been replaced. The original plastic ones were prone to wearing out and failure will result in the engine destroying itself.

(Bob Allen) #3

Hi Steven,

Check to see if the engine has been replaced with a steel sleeve version (2001-newer). Many older models had problems

and were replaced with the upgraded model. There are many owners of 2000 and older who have not had any

problems. Reasonable driving and maint. seems to be the watchword for these older models. No autocross, road races

and track racing history is best. Also check to see if the wind screen fluid resavour has cracked just out of sight below the filler top.

If it has, filling it to full will only leave water or cleaner on the ground.

My best,

Bob

Robert Allen
kabob@wavecable.com

(Stephen J. Niznik) #4

Thank you for your input. I did some reading here and gained more insight. The car I’ve bought was made with the non-Nikasil liners based on VIN. numbers. I will check or have the tensioners checked. Based on the condition of the car I believe all will be well.

(Stephen J. Niznik) #5

I met with the seller today to take pictures of the car for the insurance company. I’m not picking the car up until later this week. The seller informed me that he inquired about the tensioners and guides when he bought the car and was told they had been changed. I am taking this with a grain of salt but my hopes are up that this is something that I can forgo. Based on the condition of the car I won’t be surprised that they have been serviced.
Thanks again for your input. I hope to be communicating good stories in the future. By the way, my wife and I are going to do our first Rallye on July 1st. (in the XK8) as part of the start up to the Pittsburgh Vintage Grand Prix.

#6

I’m actually suspicious if this is a myth or reality. Has any engine with the plastic tensioners ever “exploded” on you with the end result of the “engine destroying itself?”

(Grahame Loader) #7

The reality is that the AJ8 engine is an interference engine, meaning that if the timing chain slips, the pistons will hit the open valves, destroying the pistons and the valves. The expense of rebuilding the engine is more than the car is worth. Worn or broken plastic tensioners can allow the timing chain to skip a tooth on the cam sprocket. One tooth, the engine runs rough; two or more and the pistons and valves beat each other to death.

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#8

This is what I’ve heard but it hasn’t happened to this engine yet. I’m asking for personal experience not hearsay.

(Jason Miller 1993 XJS 4.0 convertible, 1997 XK8 coupe ) #9

I’ve never had it happen to me, but then again I’ve never overdosed on heroin and died. Sometimes you just have to learn from others mistakes. It is a fact that plastic gets brittle with heat and age, of which the ones in the car have had both. My one plastic coolant crossover just gave and cracked for no reason, a little bit ago, so it’s very probable that something under constant pressure would not just crack, but basically blow apart. As for interference engines interfering with itself if a timing chain, or belt slips, I have had a couple of friends that had it happen. It’s not pretty. No, they weren’t XK8’s, but interference engines are basically the same. When something happens, you will have a significant bill on your hands. Lol :grin: On the plus side, I have a spare engine if yours goes out lol :wink:

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(Grahame Loader) #10

Call it hearsay, I prefer to benefit from other peoples experience. I’ve had enough expensive experiences that I am grateful to use other’s knowledge to save myself large losses of money.

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(melloyello) #11

Bought a 1999 XK8 for my wife about 5 years ago, she put a few thousand miles on it and had overheating problems. Car sat in the garage for about the last 4 years now has 54K miles on it. Just put in a new radiator ,crack in plastic side caps. Still losing coolant traced to leaking head gaskets. Did not want to attempt repair myself, off to Jag expert? Picked up car today a drives great, wallet $3800. dollars lighter. About $2000. of new parts, so expensive compared to my E type. All new front timing chain kit. All the guides were cracked, would have been a mess if these pieces broke off into chains. Too much plastic used in these engines, replace any critical parts as coolant pipes and stat housing with metal one. We are the third owner of this car and question the care taken by prior owners. I had recently pulled the oil pan and trans pan and all were very clean. Mechanic said there was more than normal sludge on top end for a car with 54K miles. Well the XK adventure now begins, hope the A drum in trans. holds up, may take a few thousand mile trip in Sept. if the car earns my confidence? Oh the brake light switch that also controls cruise control and trans interlock sometime does not work. New switch $165. crazy.
My wife is afraid to drive the XK because it has let her down too many times. Said she may drive it to church 2 miles away,if broken down she can walk home.
Glenn

(Bob Allen) #12

Glenn,

I was surprised that they didn’t recommend the new engine upgrade. Usually they put in the newer engine from 2001 or newer.

The piston sleaves are usually the first thing to go.

Bob Allen
kabob@wavecable.com

(Eric Capron) #13

Actually, this is not quite right. The problem with the early AJ26 engines that some people had was that the block was not sleeved but had a coating process called Nikasil. This is a very thin layer of a combination of various metal alloys, (Nickel, Silicon etc.) that gives great durability in this application and Jaguar were by no means the only manufacturer to use it. XK8s in the VIN range 001036 to 042775 were fitted with Nikasil engines, the last Nikasil engine produced having engine number 0008181043.
An unforeseen consequence of using this material was that some fuels, particularly from cheaper outlets contained a very high Sulphur content which reacted with the lining and destroyed it. A so called ‘Blow-by test’ was carried out to determine whether these early engines had been affected and Jaguar were forced to replace engines that had failed in this way. Engines replaced under this scheme have a plate identifying them as such.
After Nikasil production ended Jaguar sleeved the blocks with a steel liner and these engines are as reliable as any other in this respect.
The received wisdom on this topic is that if you have a Nikasil engine and it is alright now it will not have been subjected to high sulphur fuel and will remain OK because the sulphur content of all fuel now is much lower. I have a Nikasil engine in my XK8 and it is still perfectly good.
The timing chain tensioners, especially the upper ones and the coolant pumps are the known trouble spots on these early engines which otherwise are practically bombproof. The response curve of the temperature gauge is complicit here because like the oil pressure gauge it is designed to sit with the pointer bang on the middle of the scale for a very wide range of coolant temperatures. These intended ‘peace of mind’ gauges are anything but because you don’t discover an overheating problem until it has got serious.
Problem solved on X150 by leaving the gauges out completely as indeed also on X100s with factory fitted navigation but now I’m just ranting.
Eric
Shropshire, UK

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