Back Axle noise, especially on the over-run.
Don't be tempted to buy a car with any appreciable noise on the 'back end' You may have been told that the noise is due to a worn wheel bearing but this often not the case. Mostly, worn differential bearings are to blame.
Repair is expensive in both terms of parts and labour and there aren't many mechanics that can (or will) do the job. Finding a second-hand differential unit that is genuinely quiet is difficult, and the last thing you'd want is to spend a lot of money in having a used Diff. fitted only to find it is also noisy and the assurance that it is 'guaranteed' is worthless. The only way to buy a used unit is to stick to what you can test drive before buying and make sure that it is that unit you end up with. A new or reconditioned differential unit will set you back a long way, possibly costing half of what a car is 'worth', plus the labour of removal/refit.
Note that the labour element of this job is unpleasant to undertake, whilst seized bolts can hinder the job further. In my experience, the labour cost of removal and refit of a diff. unit is somewhere around �400 - �500, and that is without the supply/ repair of the diff. I have got 'lucky' in finding a used diff. unit that proved to be quiet but the total cost of buying it and having it fitted exceeded �800, not good if the car is 'worth' only �2000.
Digital Dashboard Clocks
I only see around 5% of cars with this clock actually working. There are replacements available from E Bay or similar, costing �35 � 70 plus fitting which can be DIY.
My position on this is that if the clock works, that's a bonus. If it doesn't, don't waste money on a thing you will rarely use. Use the clock feature on your mobile phone, Sat Nav or watch!
Oil Pressure readings low or Zero and Oil light coming on
This is a common problem, especially on older or higher mileage cars. It can be alarming as it often denotes an engine which is about to expire on other makes. Worry not. I have had several cars that have shown zero Oil pressure, normally just after warm up. The X300 engine is 'bombproof' and I have never seen one quit in such circumstances. When checked out, it always has actual Oil pressure if checked with an in-line (mechanical) pressure gauge. The cause of the errant 'Zero' pressure indication is the electronic sensor which fails to work at certain temperatures when close to the end of its useful life. The cure is to fit a new or even a used sensor. This is a relatively easy thing to do although it is hard to get at.
Boot opening (external) switch not working
The button used to open the X300 boot from outside the car operates a small switch.
This can fail, although most often the wiring that crosses the boot hinge will have become stiff and broken through. It is not expensive to fix the problem but like many electrical jobs it can soak up a lot of expensive diagnostic time. It is always much cheaper to use the boot button inside the car, or the key from outside and leave well alone!
Heater not supplying hot air
In just about every case, this is due to the failure of the electric circulation pump, fitted on the NSF inner wing. Replacements are not cheap from Jaguar although a used one might be good. Specialists like David Manners can save you money on a new one.
NOTE! If your car is LPG converted a failed heater coolant pump can cause all sorts of problems because the LPG system relies on hot coolant being supplied by the heater circuit. If it doesn't get that, the LPG system will not perform properly.
Another cause of heater failure can be Air Locking, especially if the air is trapped in the heater matrix. This problem is much that same as Air Locking in a house radiator and has the same cure. There are various methods for 'bleeding' the air out. In extreme cases we've had to raise the front of the car whilst bleeding air out of the matrix.
If you bleed the heater matirix successfully only to suffer the same problem later on, start looking for a coolant leak before things progress to a more serious level.
Screen Washer Pump not working
Most often the pump itself will have failed. It is not easy to get at, requiring the removal of the OSF inner wing liner. Jaguar charge �47 inc. Vat for a new pump although note that many types of Ford screen wash pump can be made to fit. I have bought these at �2 each from a breaker. If you go down this route, take some of the wiring and the connecting plug along for the ride. Often these differ whilst the pump is similar mechanically.
Other causes can be simple blocking of washer nozzles and pipes or failure of the in-line non return valves.
There is a pictoral 'how to' item on Screen washer pumps on one of our other Jaguar pages - Jaguar faults
Rear Bumper Top Face Bright Trim.
These are often dented by careless folk dumping heavy items on top of the bumper before opening the boot. The top trim is not chromed steel as many expect, but high quality stainless steel. A new replacement trim costs �165 plus Vat from Jaguar. They are held on by all manner of awkward clips which break easily. Also be aware that the bumper has to be removed before replacement can commence, something which brings its own problems in terms of seized bolts and broken plastic.
Add the labour cost to the cost of the replacement trim and you could easily spend �300 total. If you are lucky and the dent is not serious, it is possible to remove the trim and carefully roll out the dent. For best results, ask an experienced panel beater to do this for you � NEVER use a hammer on the back of the trim without a sandbag on the other side or you'll end up with a worse dent in the other direction!
Rear Windows not working
This is another common X300 problem which is often due to simple lack of use. The motor is not too hard to remove and may respond well to freeing oil and TLC. You can plug the motor back in when it has been removed and check it for operation using the door switch (with ignition on) but mind your fingers!
Rear Shock Absorbers � Rattling noises on the back end���
This problem is often passed off or misdiagnosed as loose exhaust mountings, items moving in the boot or perhaps a loose rear bumper. If the noise occurs most often after going over a pot hole, it is more likely that the mounting bushes and bearings of the rear shock absorbers are to blame.
If the shocks themselves look old it is often a mistake to have them re-bushed. The only way to deal with this is to fit complete new shockers or have then fitted. The Jaguar replacement items are very expensive although David Manners supply a new pair (and I'd only recommend fitting a pair) for �127 delivered.
Don't be tempted to buy cheaper items as the top of the shocker shaft can snap right off during a good jolt, meaning the job must be done all over again. Removal and refit is, like the rear differential, not a fun job. Labour cost is around �150 a side (as long as none of the bolts shear off when being undone) making the total cost of a pair of rear shocks around �450.
I do not recommend DIY for this job. The good news is that the handling of a car with worn and noisy rear shock is dramatically transformed by fitting new ones!
Aerial Mast replacement
Often these are broken, damaged or simply seized. If seizure is the problem they do not normally retract or extend properly. The major cause of seizure is lack of regular cleaning of the mast by the previous owner or driver. As prescribed by Jaguar, the mast should be cleaned every 2 weeks or so using WD 40 and a soft cloth, wiping in an upward direction only. This stops the dirt from being pushed into the joints of the mast. If the mast has to be replaced beware that new ones are not cheap - �47 from Jaguar.
Air Conditioning not working.
By far the most common used X300 fault. The cause is often no more thab lack of use by the previous owner(s). As prescribed by Jaguar, the Air Con, should be turned on every 2 weeks or so to keep it maintained, Winter or Summer. The reason for this is simple once Air Con is understood;
Air Con. has many mechanical parts that require lubrication, bearings, seals and so on. The Air Con. system contains a gas that tends to remove ordinary mineral based oil or grease. To get around this problem a special lubricating oil formulation is added to the refrigerant gas. This oil only circulates to where it is needed when the Air Con. system is working. If this oil is not circulated, mechanical seizure can result.
Secondly, the many seals that keep the gas in the system will tend to dry out and shrink if they do not get a regular supply of this special oil. If the system isn't used regularly the seals will shrink and the gas will escape, leaving the system inoperative the next time it is called upon. As a result of this there is no special oil left in the system either. You will hear many people speak of a car's system needing a 're-gas' but this is often unsuccessful. Once those seals have shrunk to a certain level they will not come back to useful life and the gas just put in will leak out within a few days. A large repair bill then looms.
It is easy to spend �1000 or so on a Jaguar Air Con. System that has been neglected. On older cars it has to be judged as to whether it is worth doing this. If you are lucky enough to have Air Con. working in an X300 or any other car, look after it by running it every 2 weeks or so. It really is a case of 'Use it or lose it'.
Note that cars fitted with 'Climate control' only but having no Air Con, system are actually preferred by many � If Air Con. isn't fitted, it cannot break!
Cars that will not allow 'Drive' or Reverse to be selected from a start
If the brake light bulbs (or the circuit that feeds them) do not work, the gear selector interlock will not release from the 'Park' position when the brake pedal is pressed. It can take ages to select a gear in such a case. Also note that the Brake light switch itself can be faulty or out of adjustment, causing a similar problem although the bulbs are both good and the circuit is working.
Front and Rear Brake Discs - Warping and Wear
Wear is clear enough to diagnose. When the brake discs become too thin they need replacing. They are checked on MOT but sometimes a 'borderline' case will be let through the MOT, only to be well below par after a period of frequent use later on. Only replace them (or have them replaced) in pairs, 2 front or 2 rear, and with new pads. If you are DIY'ing, make sure the protective coating is cleaned off the discs before fitting the pads.
Disc Warping will manifest as 'pedal bounce' and may be felt through the steering, especially in the case of front discs. Replacement as prescribed above is the only realistic cure.
Petrol Cap drain blockage and Water Contamination of Fuel
Owners still using Petrol to run their cars get to see the petrol filler every day or two but those running on LPG rarely see it!
The filler drain hole and its filter are both prone to blockage by leaves and other debris, causing the filler to collect water. This is really undesirable. The water can leak into the Petrol tank under the submerged cap and cause you all manner of problems later on.
Check that your filler drain is clear. If it isn't, take out the filter and clean it. The drain pipe itself can be unblocked with a length of stiff wire. Test it out afterward with a little water and remember to keep an eye out for the next blockage (most likely in Autumn). For pic see our other page on Jaguar faults
Car Wash Damage to Paintwork
Easy to spot and often worse on top surfaces, roof, bonnet and boot lid. The laquer finish is 'fogged' (scratched) by the coarse nylon brushes. Often the damage cannot be polished out. Avoidance is easy - Never put your X 300 through a car wash!
