X300 Service Guide

Everything you will ever need to know about maintaining a normally aspirated AJ16 X300

Words and pictures by Kim Henson of Wheels Alive

This feature first appeared in Practical Classics and is reproduced here courtesy of Practical Classics and Kim Henson

Jaguar X330 and X300 Written by Kim Henson, and using his X300 (Giles) pictured on the right, this guide covers all the normally aspirated X300 range from the 1994 3.2 (represented by Giles) through to the 1997 4.0 (represented by Brucie).





Keeping your Big Cat purring… Kim Henson takes a close look at maintaining the normally-aspirated six cylinder X300 models.

The much-loved and well-respected six cylinder X300 XJ Saloons were produced from 1994 until 1997, and were the first XJ’s to be introduced with Jaguar under Ford ownership. For this new model, it is clear that much effort was put into building in reliability and refinement. Owners’ reviews have consistently been very positive overall, and these modern classic Jaguars have deservedly earned a reputation for toughness and mechanical longevity – provided that regular maintenance procedures have been applied.



These Jaguars incorporate a variety of advanced (for their time) electronic systems, with a computer-controlled engine management system and a multitude of electrical circuits that MUST be in top condition in order to keep functioning as designed.

However, in most respects this model has proved to be very reliable in the long-term, especially the main mechanical units (engine, transmission and final drive). It is not unusual to find well-used but also well cared-for examples still functioning perfectly well on their original main units with around 300,000 or more miles on the clock…

Fortunately for owners, there are many aspects of maintenance that can be carried out at home, even if (for most owners) all or most of the electronic/computer aspects need to be entrusted to specialists.

So evaluating the running gear components and systems, lubrication care for the engine, gearbox and final drive, and basic electrical system scrutiny, are all tasks that can be undertaken by an owner.

Most components required are readily available at competitive prices, and there is a multitude of Jaguar specialists who can help/advise on these cars, in addition to which (and importantly) there is also an enthusiastic club scene for the vehicles.

If you are new to X300 ownership, I strongly recommend obtaining as much literature as possible relating to the car, including Jaguar’s own ‘Maintenance Schedules’ booklet (which tells you precisely what needs to be looked at, and when), plus the ‘normal’ X300 handbook, but also the separate ‘Vehicle Care’ handbook. All these were published by Jaguar and give much useful information. In addition, a workshop manual is invaluable too for long-term ownership and care of your vehicle.

There is also much X300 information available on various Jaguar forums (etc.) on the internet. As an example, one interesting site that frequently includes various practical notes about X300 ownership/maintenance issues, etc (within a section entitled ‘Brucie’s Diary’) is www.exclusively-jaguar.co.uk

The car featured in our photographs in this guide is a 1995 Jaguar 3.2 Sport. The X300 models were offered in 3.2 and 4.0 litre (3239cc and 3980cc) versions, and in different guises, plus a supercharged  4.0 litre and V12 6.0 litre, not covered in this guide. The models featured have generally similar maintenance requirements, and this guide is intended to be a useful resource. However, for specific information relating to your particular model, consult the relevant Jaguar literature.

The X300 is relatively complex compared with older classics, and comprehensively covering all servicing aspects could easily fill a book; within our available pages we have tried to cover as many salient aspects as possible.



Not included in our photograph/caption sequence:

  1. The diagnostic socket for electronic ‘interrogation’ of the car’s various systems is located just to the left of the driver’s footwell.
  2. The car shown in our photographs was equipped with a ZF four speed automatic transmission; by contrast manual models featured a Getrag five speed gearbox. Jaguar’s lubricant recommendation for this five speed manual unit was Dexron III (the same as for the automatic transmission, and for the power steering system). The manual gearbox capacity, for drain and refill purposes, is 1.4 litres (2.5 pints). Drain/refill with fresh fluid at least every 30,000 miles.

Manual transmission versions incorporate a hydraulically-activated clutch; check the hydraulic components for leaks/deterioration.

  1. Some examples were fitted with Powr-Lok limited slip differentials, although many had conventional units. To identify if your X300 has a limited slip type, raise both rear wheels off the ground, and, with the handbrake off, rotate one of the wheels by hand. If the wheel on the other side of the car rotates in the opposite direction to the first wheel, you have a normal/standard differential (or, possibly, a faulty LSD!). However, if both wheels rotate in the same direction, your car has a limited slip differential.
  2. The valve clearances are controlled by shims, and between cylinder head overhauls seldom, if ever, need to be checked/re-adjusted. However, for the record the figures are (cold), inlet and exhaust: 0.3 to 0.36mm.
  3. Problems can occur with a number of engine control system components, including: The Mass Air Flow (MAF) sensor, crankshaft position sensor, throttle position sensor, and the ECU itself plus connectors (water ingress causes havoc). You may need specialist diagnostic assistance to help with these aspects, also, sometimes, to re-set a high idle speed following sticking throttle butterfly flap problems and subsequent cleaning (etc.).
  4. Annually, clean/re-lubricate radio aerial.





MONEY: (£) FROM 100 (including lubricants)

DIFFICULTY RATING: ‘One spanner’ (i.e. ‘very straightforward’)



‘Jaguar’s Service Schedule for the X300 calls for most aspects to be checked/attended to at least every year/10,000 miles, whichever comes first (but more frequently if the car is used in adverse operating conditions). However, variations to this general rule, relating to specific components, are identified in our steps.

More frequent renewal of the engine oil and filter is always worthwhile in terms of component longevity and performance’.



In our captions, appropriate spanner sizes are shown in brackets.



You will need

Trolley jack, axle stands, oil drainer, metric spanners, a selection of screwdrivers, a variety of pliers/grips, a soft-faced hammer, a long steel bar/lever, oil can, protective gloves, diagnostic equipment.


Wheels and tyres

Where fitted, the aluminium alloy road wheels are easily damaged due to kerb impact (etc.); inspect very carefully.

The front tyres can often wear away unnoticed around their inside edges (these areas are somewhat hidden beneath the low-slung bodywork); make a point of checking at least once a month.

Check the tyre pressures for your specific version (consult your Jaguar’s handbook).

Wheel torque settings:

Steel wheels, 75+/–10 Nm (55+/–7 lb.ft).

Aluminium alloy wheels: 95+/–10 Nm (70+/–7 lb.ft).


Air conditioning

Frequently check operation of the system, and run it regularly, even in the winter.

If necessary, have the system ‘re-gassed’ (by specialists).


Nuts, bolts and clips

Annually/every 5,000 miles: Check the tightness/security of all fasteners.


Key fob battery

Battery renewal is recommended at least every two years/30,000 miles (whichever comes first).

It’s VERY wise to have at least TWO operational key fobs for your X300; programming to the vehicle is required, according to a set procedure (consult Jaguar literature).



  1. Front suspension/steering checks

With the car raised and securely supported (on axle stands, NOT by jacks alone), use a long, stout bar to lever up/down beneath each wheel/tyre in turn, while an assistant watches for movement (wear) in the steering swivels and suspension component mounting bushes. Examine the front coil springs, shock absorbers (dampers) and suspension arms for corrosion and any other damage.

Tech Tips

  1. When in good condition, the sophisticated suspension system on the X300 provides excellent ride and handling qualities. Note: The renewal of ailing bushes etc. can transform this model’s dynamic behaviour.
  2. Scrutinise the condition of the wheels (the aluminium alloy types are especially vulnerable to corrosion damage) and the tyres. This model is a heavy machine and is known for wearing the edges of the front tyres. The inner edges are difficult to see from a casual glance…

X300 service guide



  1. Front anti-roll bar mounting bushes

The anti-roll bar mounting bushes can deteriorate, becoming mis-shapen and unable to effectively do their job of holding the bar assembly in place (scrutinise closely). To check for excessive movement (wear), apply a long bar between the fixed mounting and the anti-roll bar, watching for movement in the bushes as the bar is carefully prised in/out against the mounting plate.

Tech Tip

If during the above test, resulting movement in the bushes is more than just perceptible, new bushes are required.

X300 service guide



  1. Front and rear wheel (hub) bearings

With the car safely supported so that the tyres are off the ground, rotate each wheel by hand, feeling for roughness and listening for grinding/rumbling sounds (indicating worn bearings). Attempt to rock/pull the wheel in/out (holding it at the top/bottom), watching for movement (Note: For the rear wheels this check may also highlight unwanted movement in the driveshafts’ universal joints). Check front wheel bearing end float every 30,000 miles.

X300 service guide



  1. Steering system components

Examine the steering rack gaiters, check for wear in the steering rack and scrutinise the universal joint assembly at the lower end of the steering column (visible from above on the driver’s side of the car). Ensure that the power steering pump is not leaking fluid, and that it is operating as it should; check its drive belt for condition and reasonable tension (don’t over-tighten).



  1. Power steering fluid

The power steering fluid reservoir is located on the right-hand side of the engine compartment, adjacent to the inner wing. Check the fluid level (a handy dipstick is built into the reservoir’s lid) and if the level is low, top up to the top (‘full’) mark on the dipstick (Dexron III originally recommended), having checked the system/pipework for fluid leaks, and rectifying if required.

X300 service guide



  1. Rear suspension

On each side, the rear suspension system incorporates a through-pin and roller bearing set-up within the lower end of the ‘upright’/hub assembly. There’s no provision for re-lubricating the pins/bearings, and long-term dirt/moisture ingress takes its toll, with wear/movement developing, resulting in uncertain handling and MoT failure. Use a long bar to lift/lower the wheel and tyre as shown, while an assistant watches for movement in the pin/bearing assembly, also in the rear shock absorber (damper) bushes, etc.

Inspect the coil springs, shock absorbers (dampers) and anti-roll bar assembly/mountings too.

X300 service guide



  1. Front/rear disc brakes

Every year/6,000 miles, whichever comes first, remove all the wheels and closely inspect the discs and pads. Check that wear is even, and ensure that the caliper pistons move freely. Note that some ‘aftermarket’ brake pads tend to squeal under light application of the pedal; this is undesirable. Always fit high quality brake components to at least original equipment specification…

X300 service guide



  1. Brake pad renewal

When renewing the brake pads, the caliper pistons must be eased back within the caliper assembly (place a rag around the fluid reservoir to soak up any spillage as the fluid is displaced). A purpose-designed tool ensures that the piston is retracted carefully and easily. If the caliper pistons are seized in their housings, deeper investigation is required. Always renew pads, calipers and (where required) discs in axle sets.

X300 service guide



  1. Brake hydraulic system

Unscrew the fluid reservoir lid, and ensure that the fluid is at the correct level, and clean. Every two years/24,000 miles (whichever comes first), renew the brake fluid (DOT 4 specification), ensuring that all old liquid is expelled, and that the fresh fluid is free of air. Closely scrutinise the fixed pipework plus the flexible hoses. Check for fluid leaks ‘everywhere’. Assess the servo unit/hose, and check the anti-lock brake system components for condition/security.

X300 service guide



  1. Handbrake cable, also exhaust system

The operating rod from the handbrake lever runs rearwards; nestling between/above the two exhaust boxes, it is connected via a yoke to a cross-car cable serving both rear wheels. There’s provision for adjusting the effective length of the rod/cable set-up, if required. If handbrake lever travel is excessive, reduce cable slack by rotating the adjuster. On completion, ensure that the rear wheels are fully locked with the lever applied, yet free to rotate with the handbrake ‘off’.

Every 30,000 miles check handbrake shoes friction material.

Inspect the entire exhaust system for deterioration/gas leaks.

X300 service guide



  1. Automatic transmission fluid (check with car on level ground)

The orange-topped dipstick is just ahead of the red-topped engine oil dipstick. To correctly assess the fluid level… The transmission MUST be at normal operating temperature (drive 15+ miles), handbrake on, transmission in ‘Park’. Allow the engine to idle for a few minutes, apply the brakes and move the gear selector through all positions and back again to ‘Park’, still with the engine idling. Withdraw the dipstick, wipe it clean then re-insert it, again withdrawing it to take a reading. If necessary, top up (original recommendation Dexron III) to ‘MAX’.

Tech Tips

  1. Avoid dripping fluid onto the hot exhaust manifold…
  2. Every 30,000 miles, change the transmission fluid and its filter. Drain/refill capacity: 3.2 litre models, 3.0 litres (5.3 pints). 4.0 litre normally-aspirated versions, 4 to 5 litres (7 to 8.8 pints). Supercharged 4.0 litre models, 7.3 litres (12.9 pints).

X300 service guide



  1. Final drive system

The final drive/differential unit is notoriously difficult to see, let alone reach, but incorporates a filler/level plug, a drain plug and a breather vent (check that this is unobstructed). Jaguar’s original ‘Vehicle Care’ Handbook for the X300 does not differentiate between standard and limited slip differentials, and advises using EP90 oil (original recommendation for refill was only to use Shell Spirax Super 90 oil). At least every 30,000 miles, drain/renew the oil. Capacity: 2.1 litres (3.7 pints).

Inspect the propeller shaft and driveshafts’ structural condition and universal joints; re-grease every 10,000 miles/annually.

Tech Tips

  1. NEVER take out the final drive unit’s drain plug until you are SURE that the filler/level plug can be reached/unscrewed (otherwise you could be stuck with no oil in the unit).
  2. Note: Many owners today recommend using an additive for limited slip differential lubrication (in conjunction with standard EP90 axle oil), or a lubricant specifically formulated for use in a limited slip unit.

X300 service guide



  1. Bodywork structure

Inspect all areas around the body shell structure, also the front and rear sub-frames to which the suspension components etc. are attached. Ensure that the sill assemblies, jacking points and floor pans are sound. Clean the underbody, then touch up any damaged areas of protective coatings. Apply wax/oil based preservative within hollow sections.





  1. Fuel system

Inspect the fuel system, watching very closely for any leaks (which can occur due to rusted pipes, especially towards the rear, close to the under-vehicle fuel filter canister – which itself should be renewed at least every 60,000 miles).

X300 service guide



  1. Sun roof (where fitted)

Wipe clean the sun roof’s seal, then apply a little silicone grease or a silicone spray to it.



  1. Electrical aspects

Wiring connections and bulb contacts can oxidise in time, especially if the car is parked outside and seldom driven. Carefully cleaning the contacts usually restores normal operation.

X300 service guide



  1. Interior

The leather upholstery responds well to occasional cleaning and treatment with a leather balm product. Test all switches, instrumentation and panel lamps. Sparingly lubricate all catches, hinges and locks; wipe away excess lubricant on completion.

X300 service guide




 Compression test

To help confirm the mechanical state of the engine, carry out a compression test; this should show fairly even readings across all six cylinders.


Electrical aspects

Ensure that all engine bay wiring is sound, also that the multitude of cables and connectors around the vehicle are in good, clean condition. The battery lives in the boot, with long main supply cables; check that these and their connectors are in good nick too.


Other aspects

Ensure that the screenwash fluid level is correct.




  1. Hidden secrets’!

If you are new to your X300 you may not realise that, under the bonnet, adjacent to the right-hand inner wing, is a lidded compartment. Within this, the car’s wonderful original tool kit and spare bulbs/fuses should be found (although, inevitably, many have ‘disappeared’). On the underside of the plastic lid of this compartment are details of all five separate fuseboxes around the vehicle, and which circuits the fuses cover, plus the correct amp rating for each fuse. Brilliant!

X300 service guide



  1. Engine oil and filter (engine warm).

At least every 10,000 miles (preferably every 5,000 miles), drain the oil (use a socket/ring spanner on the sump plug) and unscrew the ‘spin-on’ type filter (somewhat ‘buried’, low down, left side of engine). Install a new filter (having wiped clean the mounting face) and a new sump plug and sealing washer, then re-fill the sump with fresh oil. Use high quality SAE 10W40 oil (original recommendation API SH). Refill capacity (approximately): 8 litres (14.1 pints).

Tech Tip:

To carry out an X300 oil change you will need to buy two 5 litre containers of lubricant (leaving some for subsequent topping-up).

X300 service guide



  1. Ignition system

The ignition coils are located beneath a cover panel secured by three screws (Torx T30), with each coil held by two bolts (8mm spanner), and the spark plugs/h.t. leads housed beneath the coils. Treat all the ignition components with great respect to avoid damage… Recommended spark plugs (renew every 20,000 miles): Champion RC9YCC (for optimum performance) gapped to 0.9mm (0.035in). Firing order: 1-5-3-6-2-4.

X300 service guide



  1. Fuel and air filters

Every 20,000 miles/three years), renew the air filter element (every 10,000 miles for the 4.0 supercharged model). Every 60,000 miles, renew the fuel filter (located under the rear of the vehicle). Examine the rubber seal between the air box housing and the throttle body assembly, wiping it clean and renewing the seal if damaged (as it was on this car).

X300 service guide



  1. Throttle body assembly

At each service, examine the throttle body and ensure that it is clean, especially in the area around the throttle butterfly flap. Running problems can occur if the flap and its surroundings are gummed up. Use a cleaning product purpose-designed for throttle bodies, and VERY GENTLY clean away the accumulated grime using an old, soft-bristled toothbrush or similar. On completion, use a soft cloth to wipe away all residues. Idle speed 800+/–50 rpm.

X300 service guide



  1. Auxiliary drive belts

One crankshaft pulley drives a belt serving the power steering pump; the other drives a separate belt for the alternator and water pump. Inspect both belts (renew if worn/damaged) and all pulleys. Ensure that the power steering pump belt is sufficiently tight not to slip on its pulleys. For the alternator belt, deflection under firm thumb/finger pressure applied midway along the longest belt run should be approx. ½ inch (13mm). The alternator’s threaded adjuster moves the unit relative to the engine, controlling belt tension.

X300 service guide



  1. Cooling system (diligence ESSENTIAL!!!)

Throughout the year, ensure that an anti-freeze mixture strength of 50 per cent is maintained, and use long-life ‘Organic Acid Technology’ (‘O.A.T.’) anti-freeze (coloured red), ideal for aluminium. Cooling system capacity; drain/refill: Normally-aspirated 3.2 and 4.0, 7.7 litres (13.5 pints); supercharged 4.0 litre, 9.25 litres (16.3 pints).

Assess the radiator (clean matrix every 10,000 miles, also air conditioning condenser), all hoses, the water pump, the thermostat and operation of the twin electric cooling fans (make sure they cut in/out as designed); look too for coolant leaks.

Tech Tips

  1. Pay particular attention to the multi-branch hose assembly which runs along the left side of the engine bay; as it ages it can weaken and eventually may cause serious leaks which, at first, can be hidden by surrounding components… (Guess how I know?).
  2. Renew the coolant every five years or as directed by the anti-freeze manufacturer.
  3. DO NOT mix the originally specified (green coloured) anti-freeze with the long-life ‘Organic Acid Technology’ (‘O.A.T.’) anti-freeze (coloured red) as this will form a jelly which will clog the cooling system and render it useless.
  4. The long-life ‘Organic Acid Technology’ (‘O.A.T.’) anti-freeze (coloured red) is a superior product, BUT make sure the system is thoroughly flushed of the old (green coloured) product  before refilling with the new (red coloured) product.

X300 service guideKim Henson finishes the service on his X300 with fresh coolant




For cheerful, comprehensive assistance with this feature, grateful thanks to: John Farrow of J. and C. Motors in Bournemouth (Tel. 01202 429420), also to the ever-enthusiastic Rob Jenner (a mine of information on all things Jaguar), and to Jaguar specialists Marina Garage in Bournemouth (Tel. 01202 417177).

SAFETY FIRST! NEVER venture beneath an X300 (or any vehicle) supported only by a jack. Ensure that the car is on solid, level ground before attempting to jack/support it. ALWAYS use sturdy axle stands to support the vehicle. DON’T remove road wheels until you are satisfied that the car is securely on the stands.

Wheels Alive