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192 XJ8 conversions completed

XJ8's - Love 'em or hate 'em.....?

Although the XJ8 is 80% of an X300 fitted with a V8 engine, a 5 speed automatic gearbox and some interior and body trim revisions, opinions on the model tend to be polarised. The XJ8 (X308) is often labelled 'thumbs down' due to a very small number of factors, at least one of them being pretty much irrelevant today. As Jaguar saloon buyers realise that most XJ40's are now well past their 'sell by' and X300's get older, the huge price gap between those earlier models and the arguably 'less Jaguar' X350 opens up in front of them. To rule out the XJ8 is to leave a big void in the 5 - 10 year old Jaguar Saloon market.

Maybe its time to ignore the bad press and see the XJ8 and for what it really is, a very good and usable luxury car at a bargain price?

The X300 is good.....The XJ8 is even better....

The XJ8 drives even more smoothly and gives better performance than a comparable X300. It carries a lot of improvements like Traction Control and Sport Mode gearbox fitted as standard on all 3.2 and 4.0 models whilst its fuel economy is very similar, if not better. The restyled bumpers have less chrome, a great benefit to the rear bumper in particular as there is no chrome trim to be dented in the upper centre position. The sound system has a better spec. on all models and the self-dimming mirror became standard also, previously restricted to top of the range X300's. XJ8 Prices are artifically low because of undeserved bad press. Folk tend to form opinions on this heresay alone, although they have never owned an XJ8 nor have first hand knowledge of anyone who actually had problems with one. This effect has helped to create a poor image for the model.

To help redress the balance a little, here are a few up to date XJ8 facts;

1. The 'Nikasil' Engine issue

Not Jaguar's fault.....

Nikasil is a coating used to line the cylinder walls of an engine block. It is a very successful process and used in many motorcycle and utility engines today. Problems only arose when this coating was attacked by Petrol with a very high Sulphur content. Such Petrol was sold in the UK and other markets during the late 1990's although it was quietly withdrawn from the UK market in late 1998. After a year or two of Nikasil engine production both BMW and Jaguar began to see problems with their engines losing compression due to breakdown of the cylinder linings. These cars often displayed rough idling and sometimes refused to start from cold, both clear indications of Nikasil liner damage. Any Oil contamination of the air filter pretty much confirms that an engine has such liner damage although it does not automatically indicate liner damage has occured unless accompanied by the first two symptoms.

The only realistic way to for the manufacturers to repair Nikasil damaged cars at that time was to fit a replacement engine built with more traditional Steel cylinder liners. Both Jaguar and BMW replaced countless thousands of engines under warranty, and sometimes way beyond it. The problem was found to be isolated to Countries or areas where high Sulphur Petrol was being sold, whilst identical cars using lower Sulphur Petrol sold in other markets were not suffering damage at all. The fuel suppliers removed the Sulphur and the problem was cured, although this happened too late for the engines already damaged and perhaps already replaced. Some engines only had minor to medium levels of damage and missed the replacement programme although they came to light in the following years. Those cars either had the engines repaired by specialist companies or had used units fitted from other cars. When considering that this all took place some 7 years ago it is clear that there will be virtually no Nikasil engines about to display liner damage today, practially every one will have come to light during that period.

When considering the purchase of an early XJ8 (1997 - 1998) today, the buyer only has to consider two things on the Nikasil front;

(a) Was the engine replaced with a Steel lined item by Jaguar?

This can often be determined by checking the vehicle's service history, although this is not ultimately reliable. The best way to find out is to check for the Genuine Jaguar Replacement Engine placard shown in the picture below. If the engine has this placard and has been replaced as described above then you can forget all about Nikasil problems, there cannot be any.

The 'Magic Placard'

If the car's engine has been replaced with a Genuine Jaguar Replacement (Steel lined) engine it should have this green and silver metal placard fixed to the upper rear face of the cylinder block casting. If present, the placard is quite difficult to find, located just behind the offside cylinder head (RHD models). Removal of the centre plastic cover (fitted close to the bulkhead) and having a torch to hand makes things much easier. The sheathed cables passing over the placard and through the securing clip go to the Lambda (Oxygen) sensors.

The good news is that if your engine has this placard, you can forget any Nikasil worries.

(b) If the car has an original Nikasil unit;

There is every chance that it has survived liner damage, especially if its mileage was low up to the point where the problem was solved. This can be confirmed by a 'Blowdown' check at the Dealer's. Air filter, idle quality and cold starting checks should also be done, perhaps before going to the Dealer or buying the car.

If all is well, be assured that no further damage to the Nikasil liners can result from using today's Petrol, nor, for that matter, LPG as its Sulphur content is so low as not to register. To put this into perspective, the earliest (1997) XJ8 will have been running happily on today's Petrol with no risk of liner damage for far more time than it ran on high Sulphur Petrol (gone by 1998). This is supported by an interesting fact - All XK8's of similar vintage had Nikasil engines fitted but tended to cover far less mileage. As a result, they suffered no significant liner damage. We've never seen an XK8 need an engine replacement due to Nikasil damage and they run no risk of damage today or in the future.

If the car being considered was built during 1999 or beforehand....

Any concerns about the Nikasil liners can be forgotten - the engine cannot have been run on high sulphur petrol as it was withdrawn from the UK market in late 1998. No damage to the liners could have been done.

If the car being considered was built in August 2000 or afterward....

Nikasil issues can be ignored completely. Jaguar fitted only Steel lined engines after this time.

When all the above facts are considered, and due care is taken over inspection, the chances of anyone experiencing Nikasil problems with any used XJ8 are very, very small these days. It's worth remembering that countless thousands of Nikasil lined engines are sold every week, they power Motorcycles, Machinery and Garden Tools and suffer no damage of that kind now the cause has been removed.

2. Timing Chain Tensioners

A lot of attention has been paid to these in the last couple of years, and rightly so. If a tensioner fails the engine can throw off the cam chain(s). We have seen at least one V8 engine that ran very badly. On investigation it was found to be only running one bank of cylinders because the chain had come off the gearing for the other bank.

There are two different, earlier design plastic tensioners which are not up to the job in the long term. The latest revised item is made of metal and will be a lot more reliable. Ideally you'd be buying a car with the latest metal tensioners fitted. If not, just listen to the engine from cold start - If there is any clattering from the 'top end' then tensioner failure could be close. You would be wise to try and negotiate a lower price in order to get this job done right away, although it must be rememebered that XJ8's are already artificially low in price when offered secondhand. The fitting of a new water pump (only 45 or so from Jaguar) is a wise thing to do if having the tensioners dealt with as that area of the engine will already be stripped down. Fitting a new thermostat at the same time would be a smart move.

Checking timing chain tensioners on a car being considered

If the top end is quiet right from a cold start then it is likely that no immediate problems will occur. These cars were collectively driven many millions of miles with only rare failures before anyone knew there was a problem with the tensioner design. If there is no documentation showing that the later type metal tensioners have been fitted, it would be prudent to have then fitted in the short to medium term.

A lot of car for little money......

I have heard folk say that the XJ8 is 'not a real Jaguar' but having owned 30 or so I have to differ with this. From the driver's seat backwards the car is almost entirely X300. The front end is bodily the same with some minor cosmetic changes. As for the differences, the headlights are better than the older X300 design, resisting stone chips and 'fogging' of the lenses a little better.

3.2 and 4.0 litre V8 engines are much smoother than any six, even rivalling the mighty V12 for drive quality, although some folk will never accept anything other than a traditional straight 6 unit as being a Jaguar engine. This makes me wonder how they categorise the Daimler / Jaguar V8 2.5 Litre engine of the 1950's and 60's? The later 5 speed automatic gearbox keeps the engine at the peak of its torque curve a little more efficiently than the older 4 speed unit did. The overdrive of top (5th) gear has been retained. There is now a way of changing the 'sealed for life' XJ8 gearbox oil that has created a lot of discussion over recent years.

Some do not like the revised XJ8 instrument binnacle although others prefer it to the carried over XJ 40 item that the X300 was forced to live with. One other major difference that bears mention is the revised front hubs and wheel bearings - The XJ8 front hub assembly was designed to accomodate 4WD, making allowance for drive shafts to pass through the hub and bearing centre. This means that the wheel bearings (a single outer sleeve assembly) are not so easy to replace, requiring the use of a press to get them removed and new ones fitted. As far as we know, the earlier X300 hubs will not fit the XJ8 wishbone ball joints and the wheel bearings themselves are quite different, preventing recycling of complete hub units gotten from other cars. Similar differences are found if replacing XJ8 bottom ball joints. Jaguar will only supply a complete lower arm with a new ball joint fitted. The worn joint can be pressed out of the old arm and replaced by pressing a new one in, although a sound fit is clearly desirable. Having the correct Jaguar front road spring compressor to hand is an absolute must for this job. I would not recommend either front wheel bearing or bottom ball joint replacement as suitable for basic level DIY.

It would be true to say that the XJ8 is more complicated than its older sister when considering engine management, ABS and other systems, and is thus more reliant on specialist diagnostics. That said, you don't have to go to the Jaguar dealers for diagnostics these days and after all, cars made by any manufacturer went that way during the same time. Look at an X350 in this way and you'll find its complexity multipled by a factor of 10!

By this time, some may have me firmly marked as pro-XJ8 and anti-X300 but that isn't it. I like both models, although I know that if I want to keep away from body corrosion (lower portion of front wings and rear wheel arches) I probably need to buy a used Jaguar Saloon made after 1996. The XJ8 model does not suffer much corrosion and has been seriously underrated, making good, used examples far cheaper than they should actually be.

XJ8 it is for me then, and what a LOT of car you get for very little money...!

XJ8 'Niggles'

Every make and model of car has its little foibles, things that commonly cause annoyance whilst not being serious. Below, I'm showing you some that I've found on XJ8's which might help, along with some suggestions for a cure.

No Cruise Control?

Was your car built without it? We did a lot of research into the retro-fitting of XJ8 Cruise Control. The job is not as difficult as you'd think!

See our item on fitting XJ8 Cruise Control

Induction Air Leaks (Unmetered Air)

The XJ8's Airflow or Airmass meter is placed on the Air Filter Housing. Any air leak inbetween that and the throttle body will result in unmetered air induction, often resulting in incorrect fuel / air mixtures. The main symptom is engine stalling at road junctions or 'surging' of idle RPM. It is important to ensure that the air duct is fitted snugly to the top of the throttle body and has its rubber seal correctly fitted. Many air ducts have been damaged in this area by ham-fisted fitters but the car will not forgive this if it results in a leak. In exteme cases the duct and seal may need replacement.

Another air leak opportunity is afforded by the little resonator tubes which protrude from the air duct. Over time, vibration and heat take their toll, often producing a crack at the joint with the duct proper, thus allowing troublesome unmetered air to enter. XJ8's can have one or two of these resonators in various positions on the air duct and its always wise to check them. Note that these cracks can be hard to spot, often beginning at the bottom and remaining unseen until the air duct is removed for inspection.( Joint ringed in Red in the picture below)

The cure can be duct tape or a simple smear of silicon (allowed to 'go off' before running the engine) right up to more drastic measures such as cutting the tube right off and blanking the remaining hole. If you do this, make sure that nothing can come undone and be inducted! The lack of the resonator will make little difference to induction noise, some actually prefer it. That said, the only 'proper' cure for this problem is to fit a new air duct.

NOTE that because of the variable nature of airflow going into the engine, unmetered air leak problems and sometimes problems in the airflow meter itself do not show up on OBD or Jaguar trouble code reading systems. If you have no trouble codes this does not mean that a fault of this kind does not exist.

Upper Coolant Tubes (Don't lean on them!)

I've made the mistake twice now.....Leaning over the engine bay only to hear that snapping noise under my chest. The plastic coolant tubes become embrittled by heat and vibration (work hardening). In extreme cases they have the stuctural strength of a Rich Tea Biscuit and lie in wait for an unsuspecting engine bay worker. Then they pounce.....Replacement is the only long term cure (A Dealer only part) although if you are lucky (!?) enough to break a tube well away from the connector a temporary repair can be made using some tight fitting rubber coolant hose and worm-drive clips. If the connecting clips themselves break, it's definately curtains for that tube, you'll have to get a new one. Don't risk running the engine with a broken tube or clip, engine overheating is sure to follow.

Two of the Upper Coolant Tubes (Seen as very Black lines in the centre of the picture above) stretch right across the Nearside plastic cylinder head cover, perfectly positioned for the unwary leaner!

Some of the tubes can be seen connected to the Expansion Bottle in the picture below;

A much more subtle problem can lie in the connection of these tubes. If they have ever been disconnected from the Expansion bottle (Header Tank) it is very easy to reconnect them the wrong way round, especially as both tubes have the same size and style of connecting clip and the correct way to fit them (one crossing another) actually looks incorrect.

Coolant loss often results from reversal of these tubes and it's wise to check yours. I've seen many that are incorrectly fitted. For the avoidance of any doubt, the correct positioning of the top tube is shown in the picture (Ringed in Red) and the two tubes must cross over each other.

Whist we have a picture of the Expansion bottle it's worth pointing out that the Coolant Level Sensor (Ringed in Blue) is fitted into the bottom face of the tank and doesn't need much provocation to simply drop out of position. An errant 'Low Coolant' warning is often the result, along with the mental alarm that goes with it. In reality, the Coolant level will be fine whilst the sensor becoming dislodged cannot cause any leak.

Usual disclaimer here; You must always stop and check if you get a 'Low Coolant' warning

No Circuit Fault Warnings!

XJ40 and X300 owners may have become accustomed to the 'Circuit Fault' warnings that those cars give, and be misled into thinking that an XJ8 does the same. It doesn't. If you have something that does not work on your car, check the fuses etc. as the car will not give you a warning like the earlier models did. I doubt this can truly be viewed as some kind of loss as the older cars often gave these warnings in error.

Fuse Boxes

There are 5 in the XJ8. Two under the bonnet (NSF front wing, RHD cars) two under covers on the rear seat heelboards and one in the boot, close to the battery. Use the Vehicle Care handbook to check what circuits the various fuses protect.

Throttle Body (TB) Faults

These are not so common these days (there was a recall on XJ8 Throttle Bodies) but do be aware that they have a habit of NOT showing up on any OBD or Jaguar fault code reading / diagnostic systems. Most TB problems do not generate a 'fault' or 'trouble' code of any kind. This can be a little awkward to say the least. Some problems with the throttle body (idle speed surge etc.) can be cured by simply cleaning the inlet bore. This is best done by removing the throttle body and than using trusty WD 40 and a soft cloth. Pay particular attention to the area around the butterfly when at the idle position. Get the inlet bore walls spotless and you might get a nice cheap result. If you have no joy, try to borrow a known good TB from another car or better still, fit your TB to a fault free car and see if it misbehaves as a result. When fitting the TB, do NOT adjust the throttle cable too tight - Leave a little slack. I have seen at least two cars displaying apparent TB faults which were caused by the throttle cable being overtightened. Finally, some TB problems can simply disappear after both plugs have been disconnected and left overnight. The problems may or may not creep back in after some miles (sometimes hundreds) have been covered.

In all cases, resist the temptation to have a new TB fitted until all other lines of enquiry have been exhausted. New TB's are not cheap (850 plus VAT) and I'm sure many have been fitted simply for the lack of some TLC.

Errant ABS faults

First of all, note that the ABS ECU needs to 'see' signals from every wheel sensor (along with a positive result on other checks) before it will turn off the warning light. I have seen drivers sit and worry for ages over a lit warning light. All that is required is to drive the car forward a few yards, resulting in the warning light going out when the ABS ECU has 'seen' the signals it needs to see.

ABS sensors, especially on older and high mileage cars, do not like cold, damp and frosty conditions. Many's the time I've started a car from cold and seen the ABS light illuminate, only to see it clear after a subsequent (warm) start later on in the day. It would be wise to monitor the situation before parting with any money to get ABS sensors replaced. Cleaning of the rotor vanes on the back of the hub and careful cleaning of the sensor head (use WD40 and some soft but not woolly cloth) can help. Note that on earlier cars (and possibly later cars, although I haven't seen it) the illumination of the ABS warning light coupled with the failure of the speedometer can save you some money on diagnostics - The Speedometer is telling you that that the NSR sensor (RHD cars) has failed or may be suffering from the effect described above. The speedometer fails because the NSR ABS sensor doubles as the vehicle's road speed sensor.

The ABS ECU is positioned close the the back of the NS headlight and thus exposed quite a deal of damp air. The connector plug has many pins which can corrode. It is well worth removing the ABS ECU plug and spraying it with a little WD 40, then working the plug up and down the ECU connector pins quite energetically. You might just be lucky and get it working. As in the case of throttle bodies, I'm sure many new units have been fitted when the original one could have been recovered.

Finally, note that an XJ8 with a Battery close to the end of its useful life can often throw up ABS and resulting Traction Control Failure warnings simply because the Battery voltage is lower than ideal. This type of errant warning can often melt away when a new Battery is fitted. Don't skimp and fit the smallest Battery, go for the full size version and spend a few pounds extra to get one with a three year warranty. You won't regret this.

Traction Control (TC) and Stability Control (SC) Failure

The 'eyes and ears' of the Traction and Stability control systems are the ABS sensors. If the ABS system does not work, neither will the Traction or Stability Control. Note that only one ABS sensor suffering from no more than the effects of dirt, damp and cold conditions (described above) can knock out ABS, SC and TC systems.

The ABS ECU's operation (or lack of it) can also affect Traction and Stability Control. The unit is positioned close the the back of the NS headlight and thus exposed quite a deal of damp air. The connector plug has many pins which can corrode. If the ABS system is OK but a TC or SC fault is displayed it is well worth removing the ABS ECU plug and spraying it with a little WD 40, then working the plug up and down the ECU connector pins quite energetically. You might just be lucky and get it working. As in the case of throttle bodies, I'm sure many new ABS ECU units and sensors have been fitted when the original one could have been recovered.

NOTE that the Driver's Handbook is clear on these ABS, TC and SC failures (whether real or apparent). The warning given is only amber for caution and it does not mean that the car cannot be driven, it just requires what it says - Caution.

The Static Rev. Limiter.

I had a worried garage owner ring me on my mobile for advice on a Saturday afternoon (don't you just love 'em) saying that he had a fault with a car he had done a service on. The owner had come to collect the car at lunchtime and revved the engine to around 3000 with the bonnet open, only to find that it would cut out and die, then rev up again in a fast, repetetive fashion.

I told him to simply shut the bonnet and hand over the keys - All the owner had 'found' was the Static rev. limiter, put in place to protect the engine from over-revving with no load. This could happen if a driver stamped on the wrong pedal with the gearshift in neutral. The limiter is fitted to stop any resulting damage happening. Naturally the engine did not display the assumed 'symptoms' when the car was put into gear and driven.

Central Locking and Alarm Key Fob not Working

Key fob transmitters have a hard life and do wear out. It may be that new Fob Batteries (there are two, part number 2016) will bring the fob back to life. If that is the case then you are lucky. We often see fobs that have only one thicker battery fitted in error by a previous owner, and its not surprise that the fob does not then work. Fitting the correct 2 x 2016 batteries might sort things out. Again, if that is the case with your fob you are lucky, because....

A replacement fob costs around 120 plus VAT from Jaguar and then it must be adapted to the car. A secondhand one can be bought and adpated to suit the car if you can find one that works.

Cars that have 2 servicable fobs are very rare, mainly because the first fob packed up and a previous owner moved on to using the second one. To be fair, getting one working fob with a car that has covered 100k miles is a bonus. Two working fobs is almost unheard of! If you haven't got a working fob at all and don't want to replace it, you don't have to buy one at all. The Alarm will be armed and disarmed by using the key to lock the doors. When opening the doors you have to get the key into the steering lock and switch on the ignition pretty quickly to stop the alarm horn sounding. See the Driver's handbook for more on this.

Cleaning the Key Fob

If a key fob refuses to work after the batteries have been replaced, it is most likely that the PC board inside has become dirty over time. It is a simple matter to clean it, anyone can do the job.

Use a wide blade flat screwdriver to open the fob with a twisting motion Use a pricking tool to remove the board.

NOTE which way up the batteries have been fitted - They may have been upside down!

Clean the board touchpads with methylated spirit or acetone.
Also clean the back of the carbon contact buttons (not shown) and all the battery contacts. Many dead fobs are brought back to life by simply cleaning them in this way.

By the time you've gone through this cleaning procedure and are ready to reassemble the fob, you'll probably realise that you either didn't observe which way up the batteries were fitted when you took it apart, or have now forgotten which way up they were! Also, the previous batttery fitter may have got them upside down and that's why the fob didn't work. A reminder is always at hand. The inside of the keypad side plastic outer (the one with 4 holes in for the buttons) is helpfully marked '+ side down' on its inner face.

Finally, if you have read or heard claims that the key fob will 'Lose its memory' if the batteries are not replaced or refitted within seconds (or any amount of time) of dismantling the fob, just ignore them.

There is no need to rush any key fob repair. The fob is no more than the transmitter of a pre-set code held within it which cannot be lost. This fob code is memorised by the car's security module, not the fob. A fob restored to working order by battery replacement and cleaning etc. will still work if the batteries were previously flat for months, even a year or two. There is no need for fob re-registering unless the car's security module has lost the transmitted code. The retention of that code in the security module has nothing to do with the key fob batteries.

No Hot Air from Heater

A different slant on an old chestnut;

The heater output on this car was stone cold even with engine up to full temp. and the coolant was at the correct level. The usual circ. pump failure was suspected. Not wanting to rush off and buy a pump right off (I have seen this before) I checked the motor to find it wasn't open circuit. I then checked the 12V supply - It had none.

Jaguar (bless them) forgot to list this pump in the fuse list but I traced it to fusebox 'A' (The larger of the two fuseboxes on the LHS inner wing) and fuse 3, 10A. This was blown. A temp. supply was put to the motor and it was OK, not blowing a 5A fuse I put in that temp. circuit. Fuse 3 in box 'A' supplies a lot of other things too ( which are listed in the handbook ) so I decided to disconnected them in turn to see if I could stop the 5A fuse I put in position 3 from blowing. Luckily, I got it in one by disconnecting the security system sounding horn - This had been shorting out and smelt very burnt when removed. Replacing the security horn with a good used unit fixed the problem and now the car has all the correct noises and nice warm air inside.

Another car I repaired was found to have the wiring loom for the security sounder worn through and short circuiting to earth on the anti-roll bar, which had caused fuse 3 to blow.

If there is a moral, don't rush off and buy a circ. pump before all else has been checked! I hope this little account saves others some time, money and trouble.

'I can't open the boot (trunk) sometimes'

Every new crop of XJ owners brings up mostly similar misunderstandings. This is one that came up again twice this week;

Solution - Take the keys out of the ignition. Depending on how the car was set-up at the dealership, the outside boot opening button is often disabled when they ign. key is in, preventing anyone from opening the boot when you are stopped at traffic lights etc., although it can be opened using the press switch inside the car whilst the key is in the ignition.

Broken Driver's Door Check Straps.

As the cars get older, this problem becomes more common. Often the mechanism itself breaks up. It can be welded back togehter and if it has pulled through the door frame (also common) that can be repaired using load spreading washers. Another good way to get around the problem is to get a good used check strap assembly, but don't go to a breaker's yard and take off an already worn driver's side item, take off the barely worn passenger side assembly instead. It fits the driver's side perfectly and will last a lot longer than one that is close to being worn out.

Noisy Fuel Pump? Is it about to fail?

The pump may indeed be about to fail, but let me put a slightly different slant on it; If the pump were struggling to supply fuel due to some kind of restriction (say a blocked fuel filter), then you'd expect it to be noisier in operation because of the increased load placed upon it. You might then expect it to fail as a result of that increased load. It might be prudent to check the entire fuel delivery/return system for restriction before diving in to fit a new pump which, after all, is as likely to be noisy if there are other problems.

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