XJR X308 CATS buying advice

XJR X308 CATS buying advice

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RosyG550

Original Poster:

10 posts

2 months

Tuesday 30th June
quotequote all
Hi, this is my first post on PH so apologies if my question has been answered before or if it comes across as at all naive.
I’m currently patiently keeping an eye on the classifieds for a Jaguar X308 XJR having hankered after one for years and years. I’ve been trying to do all the research I can and I’m not going to rush into anything. I’m obviously hoping for one that’s as rust free as possible and that’s been well serviced and cared for etc and although I have in my head dream specs and colours etc, I wouldn’t buy one just because it was dark grey with a heated windscreen or whatever. I’m also aware of timing chain tensioners etc.
One question I have which I can’t seem to find a definitive answer for is whether it’s preferable to have an XJR with or without CATS Suspension. My priority is ride comfort / how it deals with the UK’s often awful road surfaces rather than how sharp the handling is. Also, if CATS is a must have for optimum ride quality, is it something that can be retrofitted by clever Jag specialists? I’m assuming having standard suspension is cheaper when it comes to replacing suspension components etc.
I know these cars are pretty old now and I know I can expect problems and bills and frustrations of all sorts but I just love the look of this particular era of XJ more than any other and just love the thought of hearing the 4l V8 starting up when I turn the key! I also know objectively the X350 is a superior car in many ways and actually I do quite like the very late X358s with the facelifted front end, but I don’t love it like I always have done the X308.
Thanks in advance for any advice or info!

Simpo Two

72,233 posts

221 months

Tuesday 30th June
quotequote all
RosyG550 said:
My priority is ride comfort / how it deals with the UK’s often awful road surfaces rather than how sharp the handling is. Also, if CATS is a must have for optimum ride quality, is it something that can be retrofitted by clever Jag specialists? I’m assuming having standard suspension is cheaper when it comes to replacing suspension components etc.
Hi Rosy and welcome to PH.

My limited understanding is that CATS only makes the ride firmer ('sporting') not softer. and it's another gadget that might fail.

Whether or not the ride is 'good quality' is up to the preferences of the driver. Some like to go round the Ring at 140mph and have no roll, others like to be able to cross a pothole without losing a filling...

RosyG550

Original Poster:

10 posts

2 months

Tuesday 30th June
quotequote all
Thanks for the reply, I have a feeling I might be better off without the CATS as I don’t envisage flinging it around bends that much, I’m imagining wafting along quietly with the occasional bit of putting my foot down on the straights, also effortless overtaking on the motorway appeals. I’m definitely interested in people’s experiences of both with and without the CATS though. I’m sure you’re right about it being another gadget to go wrong.
I sometimes wander if I’d be better off with the normally aspirated V8 which I did get to drive a few times when they were new and loved it. But I prefer the look and detailing of the R and as it’s not for everyday use I really do fancy the extra power and especially torque of the supercharged version.
I’m in Wales where we’re still not allowed to travel more than 5 miles but once things are a bit more normal I’m going to try and drive a few.

Jaguar steve

6,455 posts

166 months

Tuesday 30th June
quotequote all
CATS shocks are expensive to replace.

Ride quality is subjective of course but IMO none of the X308 range on touring or sport suspension ride anywhere near as well as earlier XJs.

You main enemy even more now will be rust but looks like it's time to drag this out again - the JS X308 Buyers Guide

OVERVIEW

To avoid model confusion between the 8 XJ models the 1997-2002 V8 engined XJ8 can be referred to by its factory designation as the X308. The all new at the time V8 engine in the 308 has similar architecture to current cars and is available in a 3.2, 4.0 with VVT and a supercharged 4.0 and all versions are 5 speed auto only.
Engines were revised in the late 1999 model year from the original AJ26 version to AJ27. A car fitted with the revised engine version can be identified by a VIN number ending in five , not six digits. AJ26 engines suffered weak water pumps, thermostat failures, secondary timing chain tensioner and throttle body failures and had a Nicasil coating applied directly on the cylinder bore walls rather than using conventional steel liners pressed into the block.
ENGINE NICASIL
Some Nicasil coatings errroded due to a combination of high Sulphur content fuel and repeated short trips. Sulphur maximum allowable limits in petrol were lowered considerably in Jan 2000 so any pre 2000 Nicasil coated engine that you know for sure is OK now should not be any concern. Several Nicasil engines were changed under warranty so you may find a pre 2000 car with a later steel lined engine fitted - identify this by the presence of a green tag on the head buried at the back of the RH bank and the engine change should also be recorded in the history. Symptoms of erosion and loss of compression are fast cranking, poor cold starting, a lumpy idle and heavy oil deposits in the breather system and air intake. Crankcase pressure will be high too – a quick check for this is to undo and slightly lift the oil filler cap at hot idle. There should be little or no internal pressure or fumes escaping. Jaguar dealers can perform a blow by check to determine engine condition. A good condition engine will show less than 20l/m anything over 30 l/m is shagged.
ENGINE COOLING
Impellors on AJ26 water pumps can disintegrate giving a loss of efficiency leading to overheating and potential head gasket failure. An early pump can be changed to the later version with a metal, not plastic impellor. The temperature gauge is software driven and is not always an accurate refection of actual coolant temperature.
For an indication of water pump efficiency, remove the coolant header tank cap when the engine is absolutely stone cold, start up and gently increase engine speed. If the water pump is healthy you should see a strong stream of bubble free coolant into the tank.
Thermoststs can jam either open or shut.
You may be able to identify the later type of pump by the presence of a black plastic, not metal gasket, but the only certain way is to remove the pump and have a look. Spring type coolant hose clips can loose tension and let pipes blow off and some plastic parts on the hoses, unions and thermostat housing are very delicate. Check all over the engine compartment for evidence of coolant leaks, particularly around the thermostat/filler cap tower and coolant (valley) pipes underneath the inlet manifold as well as around the expansion tank hidden under the front of the nearside wing. Leave the engine idling to make sure the cooling fans kick in. Sniff around too as hot coolant has a distinctive smell. Auxiliary heater pump failures cause loss of heat output in the cabin at low engine RPM. Two types of coolant available for the XJ8 - don’t mix the later orange long life one with the earlier green one.
ENGINE THROTTLE BODIES
AJ26 throttle bodies all ought to have been changed to the later design under a factory safety recall. Some of the early bodies suffered from failing actuating motors causing to the engine to cut out completely on a high speed overrun. The later design should have been factory fitted to all cars from VIN 043775 onwards.
SECONDARY TIMING CHAIN TENSIONERS AND CHAINS
The only post AJ26 revision engine issue that remains is the secondary timing chain tensioners. These were replaced by a mk 2 version in Oct 1998 from engine no 98102106XX but the mk 2 type still had a plastic body which can crack or break up leading to slipped or broken chains. Mk 1 tensioners are actuated by engine oil pressure and failure can often be identified by a sharp rattling noise similar to a bicycle chain dragging on the chain guard on a cold start. The mk2 type is permanently tensioned by an integral spring instead which means it’ll usually fail silently.
A permanent solution is to retro-fit the later mk3 version tensioner made with a metal, not plastic body from the later 4.2 incarnation of the V8 engine. Jaguar issued a TSB in 2005 advising the fitment of these to the X308. Only way to be sure of which tensioners are fitted to an 308 is to either have a receipt with tensioner part numbers C2A1511 and C2A1512 which are the metal bodied type and the required 4 shorter bolts to fit them on it relating to that particular car or remove the RH cam cover - the LH is a PITA to get off - and have a look. A reddish/orange (mk1) or cream (mk2) plastic tensioner body is bad news, a grey aluminum metal one (mk3) is good.
The cam phasing on the V8 places uneven loading on the timing chains and they can stretch at high mileages or on neglected cars. If this is identified then a full chain and tensioner replacement is required costing up to £1000. If the chains and sprockets and guides are servicable then it’s a sensible move to fit the mk3 secondary tensioners which is a fairly easy DIY job. Tensioners cost around £75 a set plus a couple of quid for new bolts. Camshaft setting tools can be hired from the Jaguar Enthusiasts’ Club. Secondary tensioners can also be changed without any setting tools by tie wrapping the secondary chain to the exhaust cam sprocket and jamming the chain on the inlet cam sprocket with a wedge of wood to preserve the timing and removing the exhaust cam alltogether. Taking the cam out gives just enough room to ease the secondary tensioner away from position and fit a replacement. Chains slipping one tooth – usually on a cold start - will give a very rough running engine, more than one tooth slipped means exhaust valves will contact pistons.
A good general rule of thumb for engine condition is quiet running with just faint injector tick audible and internal cleanliness. Bright shiny metal inside the oil filler cap and dipstick along with clean oil and no evidence of leaks is a good sign, as is clear coolant that does not smell or taste bitter or acrid.
GEARBOX/ DRIVELINE
X308 gearboxes were marketed as “sealed for life” meaning no oil changes are called for in the schedule to reduce servicing costs. It's a ZF unit in the n/a cars and a Mercedes one in the supercharged cars. Any hesitation or engagement of Drive with a jerk as the engine speed rises means a potential gearbox failure looming and any gearbox stuck in 4th or 5th or only driving in reverse is beyond saving. A very faint gear whine may be heard in intermediate gears but any gearbox issues or concerns are potentially fatal. An oil and filter change might be all that’s needed to cure a gearbox malfunction like occasional reluctant or rough changes but that’s never guaranteed. Gear changes should be seamless and quiet and you should have instant response using the throttle, Sport switch and J gate selector.
Ideally the gearbox oil and filter should be changed at 50k then at 25k intervals; it's not a simple drain and refill on the ZF box as the final fill has to be done quickly with the engine running and within a narrow temperature range. There is no conventional dipstick for checking oil level.The ZF 5 speed box on the n/a cars requires Esso/Mobil longlife LT 71141 fluid also known as Lifeguard Fluid 5 and not conventional Dexron 3. The Mercedes gearbox in the supercharged version is also sealed for life but the same change requirement apply although you can use standard Dexron 3 in this box and once you have fitted a temporary dipstick it’s a much less complex job to do. Some transmission specialists offer a flush and change service done via the rather fragile oil cooler pipes in the radiator which also gets most of the oil otherwise retained in the torque converter out.
The same sealed for life marketing applies to the rear axle. Oil ought be changed but there’s no drain plug so old oil has to be vacuum extracted out of the filler plug. Refill with a API GL5 75 or 85/90 oil. Whiny diffs - a high mileage Jaguar speciality feature - can be quieted down considerably with EP140 or even EP250 oil.

BODY, PAINT AND CORROSION
Substantially better than earlier Jaguars. But look for corrosion round the rear wheel arches, round the front and rear screens especially underneath the screen rubbers in the bottom corners, bottom of the front wings, sill closing panels, jacking points and most importantly on the inner wing behind the front shocks on both sides. There's a reinforcing plate where the engine sub frame V mount is bolted to the body rail and some cars have corroded badly here. Corrosion around the same area may also be visible in the engine compartment on the top of the body rail around the heads of the two 10mm bolts that retain the top of the V mounts. Corrosion here is an MOT fail and a big welding job if the subframe has to be dropped. Another area to check is the joint between the rear of the front inner wings and the bulkhead. Body and paintwork is otherwise pretty good however some darker coloured cars suffer from peeling lacquer. Darker cars often appear to have slight but consistent orange peel in the lacquer all over the body too but you can use this to spot inconsistencies and start thinking about accident damage repairs. Bumper corners are susceptible to damage and bumper mounting brackets can corrode. Lacquer on the XJ8 is soft and easy to scratch with careless washing Providing you can’t actually feel scratches with a thumbnail and the paint colour underneath is OK it’s possible to restore the bodywork to a glossy finish with a mornings detailing if that's your thing. Stripe down body flanks if car has one is hand painted and not always completely straight.
INTERIOR
Very cozy given the size of the car. Always leather with different levels of trim and seating style. Wood trim clips on and is easy to change to different design. Driver’s seat back and steering wheels tend to suffer from wear. Head linings can sag. LWB version has extra room in the back. Check everything and repeatedly cycle the whole climate and a/c system through all vent operations and temperature range and run the interior fans at high speed while doing so and listen for vibration. Foam can get dislodged from the flaps and jam in the fans.

SUSPENSION, TYRES AND BRAKES
X308s are heavy and can be hard on suspension and brakes. Listen and feel very carefully for any clonking or knocking over bumps and make sure the car comes to a straight judder-free stop under both light and hard braking. Stop the car on the handbrake to make sure it works. A sharp rattle heard and felt through the steering over bumps combined with a little free play in the steering wheel may be a worn crush joint on the lower steering column. A clattery rattle from the rear is likely to be either failed shock bushes or worn rear silencer hangers. A soft clonk from the front might just be anti roll bar bushes. X308s with weak rear A frame bushes or worn rear hub pivots will tend to self steer and wander about under hard acceleration.
Look and feel round the tyres for uneven wear patterns; any suspension wear or bush failure allowing incorrect geometry will cause tyres to feather badly and excessive wear in the inside edges of the fronts is sometimes a symptom of excess negative camber from wishbone bush or ball joint failure rather than excess toe out. There is a subtle bifference in the two wear patterns with excess toe out usually causing a even slope across the tyre and excess camber more likley to show a sudden step up in wear on the inside 25%. Slight and even feathering inside and out is normal on the front tyres.
308s are very sensitive to wheel and tyre imbalances or damage, typically you'll feel a steering wobble between 50-70MPH and possibly vibration through the seat from anything over 45MPH if there are any tyre problems or buckled wheels. A Hunter Roadforce wheel balance may help diagnosis. Incorrect tyre pressures and knackered or faulty tyres will severely influence handling and ride. Most X308s exhibit a faint exhaust harmonic around 50 and another one at 65MPH. You might possibly experience a hint of driveline vibration through the body too. Don't expect too much in the way of the legendary Jaguar ride quality either - it's acceptable on touring (black shocks) suspension and 16" wheels but sport suspension cars (green shocks) have higher damping rates and have a thicker front anti roll bar and one fitted on the rear too which when combined with larger diameter wheels and lower profile tyres gives a hard crashy ride on poor roads. CATS suspension may be fitted as an option to any X308. CATS has electronically controlled valves in the shocks to vary the damping rates depending on driving style. Identify CATS by the presence of a plastic cover over the top of the front shock absorber with a lead going into it.
ELECTRICIAL/ OBD2 DIAGNOSTICS
Electrical systems are generally pretty robust. As with any old car you might have the odd problem so check absolutely everything works. X308 is OBD2 compliant and a £20 code reader plugged into the socket in the driver’s footwell will help diagnosis a lot. Electric aerials are easy to damage but easy to replace, there are occasional O2 sensor, airflow meter and brake light switch failures. Non working key fobs usually need nothing more than new batteries, a clean and easy DIY reprogramme. 308's need a strong battery to avoid random error messages appearing on start up. If you get one – usually TRAC FAIL – the battery is on its way out or needs several days on a trickle charge to bring it back up to full capacity.
BUYING AND LIVING WITH AN XJ
Generally the 1997-2002 XJ8 is a strong car and capable of big mileages if maintained well and not abused or neglected. It's mostly easy enough car for a competent DIYer to work on and parts are pretty reasonable and in good supply from several independents and the Jaguar Classic Parts scheme. The few specialist tools required can be hired from the JEC.
Expect around 26/8 MPG on the motorway or touring, between 20 and 24 around town and mid teens or less if you're nailing it in a n/a car, the supercharged versions typically use more. Quality tyres start around £100 a corner in 16" diameter size. Early cars fall into a cheaper VED bracket then later ones. Servicing schedule is annual or 10000 miles. 70k service is the expensive one on n/a cars
3.2 does 0-60 in 8.1s and the 4.0 is a second quicker.
Shortening intervals between servicing and using a genuine fully synthetic oil is worthwhile IMO. It’ll help protect the timing chains and give a small improvement in fuel economy. Keeping oil topped up to the maximum mark - both my V8's have used a little - is a plan too as it reduces stress on the oil and both reduces the possibility of oil starvation on rapid cornering and seems somehow to make a subtle improvement in refinement. A through rust proofing and full fluid change is a benefit too if you want to preserve the car. Waxoil has the effect of lubricating suspension components and a good soaking - not anywhere near the brakes 'tho please - will subtly improve the ride quality.
Keeping the inside of the throttle body and the elements of the airflow meter spotlessly clean as well as the 2.5mm calibrated bleed hole in the breather system will stabilise and improve throttle response and consistentency especially at small openings. Again it's a subtle but worthwhile improvement. Any leaks in the air intake or breather system need fixing.
Providing the suspension components are all OK and the tyres are reasonable a occasional Hunter full 4 wheel laser alignment geometry check and reset will improve feel of the car dramatically. Small changes in tyre pressure have a unusually big influence on how the car drives too.
One last thing. A software error means its a very bad thing to start an X308 from cold and then switch off again straightaway or before allowing the temp gauge to move off the cold section of the scale. There's a chance are it’ll flood when you next start and wash all the oil of the bores and it’s a right PITA to get it running again.

RosyG550

Original Poster:

10 posts

2 months

Tuesday 30th June
quotequote all
Thanks for that guide Jaguar Steve that’s amazing, what detail!
I know ride quality is a very subjective thing. I do remember driving the XJ8 with I think 17” wheels and presumably standard suspension back around 1999 and thinking then that it wasn’t exactly perfect over bumps and rutted surfaces. But I do remember it being very quiet and lovely to drive on the motorway. I wandered if the R might be slightly better ‘damped’? Sometimes on our roads slightly tighter / sportier set ups can be in a way more capable of dealing with bumps without being crashy. As long as the trim isn’t rattling horrendously I don’t mind!

Simpo Two

72,233 posts

221 months

Tuesday 30th June
quotequote all
I think that generally the further you go back, the more 'magic carpet' they will be, it's a lost art unfortunately. The quietest smoothest car I ever had was an XJ40. My S-Types were pretty decent too.

I guess an XJR will be firmer than an XJ but Steve will confirm.

RosyG550

Original Poster:

10 posts

2 months

Tuesday 30th June
quotequote all
I agree Simpo Two I think it is a lost art. Even new Rolls, Bentleys etc get criticised by some for having slightly ‘jittery’ or unsettled ride in some situations, I think the modern obsession with huge wheels and low profile tyres may have something to do with it. I’m willing to compromise with the 308 XJR though!
I’m probably alone on this but I personally really like the look of smaller diameter wheel designs that you see on older (70s, 80s etc) cars, I was browsing Racing Green Cars website and saw a pic of a Series 3 Daimler Double Six they’d recently sold, the relatively small pepper pot wheels with great big thick profile tyres, it looked wonderful imo. I like the ones on the series 2 XJ coupe too. I better stop now or I’ll start listing all my favourite wheel designs from the last 50 years.

a8hex

5,162 posts

179 months

Tuesday 30th June
quotequote all
I believe the X308 XJR is supposed to give a better ride than the X300 XJR, which is found a little jittery for my taste back when they were new. I preferred the "Sport" version, which was the Goldilocks model.

Jaguar steve

6,455 posts

166 months

Tuesday 30th June
quotequote all
RosyG550 said:
Thanks for that guide Jaguar Steve that’s amazing, what detail!
I know ride quality is a very subjective thing. I do remember driving the XJ8 with I think 17” wheels and presumably standard suspension back around 1999 and thinking then that it wasn’t exactly perfect over bumps and rutted surfaces. But I do remember it being very quiet and lovely to drive on the motorway. I wandered if the R might be slightly better ‘damped’? Sometimes on our roads slightly tighter / sportier set ups can be in a way more capable of dealing with bumps without being crashy. As long as the trim isn’t rattling horrendously I don’t mind!
These ones?



Those are the 17 inch Celtics which were usually - but not always - fitted as part of the Sport suspension option. I had that on my first X308 and found the ride way too harsh on poor roads

Simpo Two

72,233 posts

221 months

Tuesday 30th June
quotequote all
Jaguar steve said:
Those are the 17 inch Celtics which were usually - but not always - fitted as part of the Sport suspension option. I had that on my first X308 and found the ride way too harsh on poor roads
That's not all the fault of the wheel though is it (and 17" is as small as you're likely to get) - the shocks and springs are most of the battle.

Basically if you see the word 'Sport' it will be a worse ride.

RosyG550

Original Poster:

10 posts

2 months

Tuesday 30th June
quotequote all
Jaguar steve said:
These ones?



Those are the 17 inch Celtics which were usually - but not always - fitted as part of the Sport suspension option. I had that on my first X308 and found the ride way too harsh on poor roads
Yes those exact wheels. It was definitely an XJ8 4L, I don’t think it had the chrome around the windows. It definitely had the XJR style mesh grille so I wander if it was some sort of sport spec as opposed to Exec or something? You could certainly feel the imperfections in the road but it was still lovely.
My dad had a couple of XJ40s in the late 80s, I do seem to remember as a passenger that they were very smooth riding. He briefly had series 2 XJ6 in the late 70s, I think it was beige from vague memory - he maintains it was the worst car he’s ever owned, maybe it was a BL era car? I wish I could remember if it had the magic carpet ride though!
I wander if companies like Racing Green or KWE do any suspension ‘upgrades’ which improve the x308’s ride? I kind of like the idea of keeping everything standard though.

Jaguar steve

6,455 posts

166 months

Wednesday 1st July
quotequote all
Simpo Two said:
Jaguar steve said:
Those are the 17 inch Celtics which were usually - but not always - fitted as part of the Sport suspension option. I had that on my first X308 and found the ride way too harsh on poor roads
That's not all the fault of the wheel though is it (and 17" is as small as you're likely to get) - the shocks and springs are most of the battle.

Basically if you see the word 'Sport' it will be a worse ride.
Absolutely. The wheels - actually it's the tyre profiles - themselves make little difference between 60 and 50 profile it's the spring and damping rates that are the killers and the fact the sport suspension X308s ride some 10mm lower and have a thicker (IIRC) anti roll bar the front as well as one on the back whereas the touring suspension cars don't.

Jaguar pretty much lost the plot with regard to ride quality in the late 90s. I want my old Series 3 back. cloud9

Jaguar steve

6,455 posts

166 months

Wednesday 1st July
quotequote all
RosyG550 said:
Jaguar steve said:
These ones?



Those are the 17 inch Celtics which were usually - but not always - fitted as part of the Sport suspension option. I had that on my first X308 and found the ride way too harsh on poor roads
Yes those exact wheels. It was definitely an XJ8 4L, I don’t think it had the chrome around the windows. It definitely had the XJR style mesh grille so I wander if it was some sort of sport spec as opposed to Exec or something? You could certainly feel the imperfections in the road but it was still lovely.
My dad had a couple of XJ40s in the late 80s, I do seem to remember as a passenger that they were very smooth riding. He briefly had series 2 XJ6 in the late 70s, I think it was beige from vague memory - he maintains it was the worst car he’s ever owned, maybe it was a BL era car? I wish I could remember if it had the magic carpet ride though!
I wander if companies like Racing Green or KWE do any suspension ‘upgrades’ which improve the x308’s ride? I kind of like the idea of keeping everything standard though.
IIRC all 4.0 X308s had sport suspension as standard but you could spec touring when ordering. The only exception was the Sovereign - that had touring suspension as standard.

Tyre pressures make a noticeable difference to ride and fuel consumption on the X308. There's a permitted range of some 6 psi between lowest and highest and worth playing about with. I've found a comprise toward the higher works for me and run mine at 30F/32R

RosyG550

Original Poster:

10 posts

2 months

Wednesday 1st July
quotequote all
Interesting that tyre pressures can have such an influence on ride, I’ve read the same about Porsche 911s. I’ll take my little gauge with me when I start looking at cars in the flesh.
I’ve started wandering about the lwb 308s and how the extra length effects ride, I’d have thought maybe the Daimlers especially would have had the best ride as they were aimed at people who want chauffeuring about the place?

a8hex

5,162 posts

179 months

Wednesday 1st July
quotequote all
Jaguar steve said:
Tyre pressures make a noticeable difference to ride and fuel consumption on the X308. There's a permitted range of some 6 psi between lowest and highest and worth playing about with. I've found a comprise toward the higher works for me and run mine at 30F/32R
The tyre pressures make a difference on the X300 too, the owners manual lists 27PSI all round for "comfort" and that has always been my preferred setting. These are 16" wheels with 55 profile tyres.