Ka steering racks, both manual and power assisted, are known to fail and can be an expensive repair. However, your symptoms point to the power steering pump, and there have been problems caused by the power steering fluid reservoir being too small - this results in air getting into the fluid, which could well cause the noise and heavy steering. Check with a Ford dealer, and try asking for a free replacement if yours is the smaller unit.

I have an Alfa Romeo 156 on a 51 '01 plate. Whilst driving at 70mph the bonnet shot open smashing the windscreen, denting the roof, bending the supports, and crippling the bonnet. I had driven more than 300 miles since the bonnet was last opened so this would appear to be a bonnet release failure, not that I forgot to close it. I am reluctant to claim on my insurance as I feel this has been caused by a defect to the car. I have contacted my local Alfa dealer who have told me there was a recall for the Alfa bonnet catch and my car has been 'done'. Do I have a leg to stand on with Alfa or will I have to claim through my insurance? Greg Black, Bournemouth

The bonnet catch is exposed to salt and grime from the road surface. As a result it can stick in the open position unless it’s regularly greased and, if necessary, cleaned. After a few cases of bonnets flying open, Alfa did issue an instruction to dealers to check the catch, clean it up (or replace it if it was excessively corroded) and then make sure it is regularly checked and greased (i.e. at every service). This regular check and lubrication is vital. The fact that your car has been “done” simply indicates that the catch was checked, cleaned and lubricated at the time. After that, the important thing is regular maintenance to keep it free of salt and well greased, which is down to whoever services the car. If it’s the local dealer, go back and talk to them, but it’s their liability, not Alfa’s, if the catch wasn’t greased in line with Alfa’s instruction.

I have a Ford Fiesta Zetec. I recently topped up my screen washer bottle and since then it hasn’t been not working. The pump works fine as I can hear it and when I tried it following the top-up a few trickles of water came through both the front and back nozzles but now nothing. The water level on the bottle isn't going down at all. I suspect there is an air lock somewhere, but how can I fix it? John Garner, Clitheroe

The symptoms suggest a blockage to the pump inlet. After a few years you can get all sorts of gunge forming inside the washer bottle, dependent on how often the washers get used, whether you always use a screen wash additive and so on. The best solution is to take the washer bottle out, along with the pumps, and clean it out with hot water and detergent. You may have to remove a couple of other bits before you can get the bottle out, but it’s not too bad a task if you’re the DIY type. Be careful when you remove the pipes from the pumps – they can be very tight and it’s possible to snap the pump outlet pipe. Pour hot water over the pipe at the pump to soften it, turn the pipe back and forth to loosen the seal, then ease it off. Alternatively, if you don’t feel up to this, disconnect the pipe from one of the nozzles (again, take car, they’re tight) and blow through it back to the washer bottle. With luck you’ll clear the obstruction. Then put the end of the pipe into a container and operate the pump to drain the washer bottle, refill it with hot water and detergent and pump through into the container.

The roof of my two-year-old Peugeot 307CC only partly closed during a thunderstorm, and consequently the car filled with water. The breakdown service could not rectify the problem as they could not access the boot to isolate the hydraulic system in order to close the roof manually. Is there a history of problems with the roof of the 307CC? As the car was subjected to about four hours of rain how can I ensure that it has been dried out properly and that it won't happen again? Gill Mitchell, Newent

There have been reliability problems with the Peugeot folding hardtop - just as there were when it was first installed on the 206CC. The roof is a clever design and looks good, but from a technological standpoint it’s relatively simple; a few servo motors, hydraulic rams and linkages, with a number of microswitches controlling the action. It tends to be these microswitches that cause the problems, but you do need to get the cause of the failure properly diagnosed and cured.

As for drying it out, there’s no better method than lots of driving in dry weather with the top down - hopefully the recent heat wave has done the job for you.

I have a 2.8 diesel Mitsubishi Shogun automatic. It has started to stick in third gear, only resetting itself after the engine is switched off. It has been in the garage for diagnostics and they have changed one of the batteries and the alternator but I’m still having problems. Any help would be gratefully received. Alison Colman, Wirral

If you get gear-changing problems on any automatic, it’s always wise to check two things first, because they’re simple to check, cheap to adjust and cause a large percentage of the problems. The first is the gear selector adjustment, the second is brake band adjustment. A DIY manual will give details of how to do both of these.

Beyond that, you don’t give the age of your Shogun, so it’s hard to say how the box operates. Older units have a three speed gearbox, torque converter lock up, then a switchable overdrive. The hydraulically operated clutch on the overdrive unit was prone to wear which leaves the gearbox in third. The solution is a gearbox rebuild. More recent boxes are electronically controlled and the problem could be a sticking solenoid. A good auto transmission specialist will soon tell you the problem.

I have a 1999 Jaguar XJR. Recently I have started to hear a "clunk" coming from underneath the car when the automatic transmission changes in and out of low gears at low speeds. It only occurs after driving for some time, normally in traffic jam situations. The noise occurs also when braking to a stop, as the transmission kicks down a gear. Any suggestions as to what this could be?
Benjamin Bullock, London

The most likely cause is some wear in the propshaft or driveshafts, followed by wear in the differential. Putting the car on a ramp with the wheels raised will soon show which. If not, there’s the possibility of wear in the gearbox. Have a look at the transmission casing for any signs of oil leaks. Jaguar did not make any provision on these cars for checking the gearbox oil level, or for changing it, so if there is a leak, the oil level is likely to end up far too low.

I have owned a Cupra Leon 1.8 20VT on an 02 plate for 14 months and had it regularly serviced properly. This morning I was driving along and suddenly all power was lost and the battery warning light came on. The first thing I checked was the cam belt. Pleased to say it is still there as it should be. The car turns over and fires but does not run. Can you please help me with this one? Carole Powell, Sherborne

The difficulty of diagnosing this type of problem without being under the bonnet of the car is that more information is invariably needed. You can go quite a long way towards identifying the cause of the trouble armed with nothing more than your eyes and ears, but you need to make some very precise observations, particularly about the sequence in which things happen. For example, you said that the power was lost and the battery warning light came on. But at precisely what point did the battery warning light come on? If it was at the same instant that you lost power, before the engine ground to a halt, it would indicate an electrical problem in the supply to the ignition powered circuitry - a main relay for example. If the battery light came on as the engine stopped, the fault is elsewhere.

You say the engine fires but will not run. Does it fire up and try to run normally while you have the key in the start position, only to die immediately once you release the key? Did it run for a couple of seconds when you first tried but now won’t run at all? Or does it just fire occasionally as you are cranking? The difference is important; the first suggests an electrical problem in the vicinity of that main relay, the second suggests a fuel pump or supply problem, the third points to more tests for ignition circuitry, fuel pump, fuel supply and so on. If the car fires, it could even still be a cam belt problem - it can jump a tooth or so and put all the timing out to give the symptoms you describe, especially if you changed down a gear at fairly high speed immediately before you lost power. However, it’s very difficult to give specific advice with this amount if information, so your best bet is a garage I’m afraid.

My wife has a Citroën Saxo. Since its last service, when she uses the handbrake (whilst on a steep hill), she finds it sticks and has to reverse to free it. Does this mean the handbrake needs replacing? David Roberts, Malmesbury

Was any work carried out on the brakes at the last service? If so, go back to the garage and ask them to correct the problem. It’s not likely to be anything major; the brake shoes are jamming in the drum when they’re put under a load in the parking position. There are three main possible causes. First, the handbrake mechanism is dirty, worn or seized, in which case it needs dismantling, cleaning and reassembling with new parts as necessary; second, the handbrake mechanism has been assembled incorrectly - go back to your garage and ask them to check; thirdly, brake shoes of a different make or type may have been fitted. Although after market manufacturers will supply lots of “pattern” parts that conform to the manufacturer’s specification, they don’t always work quite as well as the original part. I do come across problems caused by pattern parts where the only solution is to fit original equipment replacements.

I have a 1992 BMW 325 SE (E36 model) with only 45,000 miles on the clock. I have had it for seven years, but in that time the air con has never really worked properly. Three years ago the air con system was changed so that it could accept the new gas that is used. However, it still does not blow out icy cold air. In fact, on a hot day, the air that blows out will not even cool the car. There is no gas leak either. Any suggestions as to how this can be sorted out? Thanks. Sukhjit Dadar, Kingston Upon Thames

The extent of cooling is influenced by the ambient temperature, but it should get cooler than this. It is possible the air blender is not shutting off the warm air. Take the vehicle to a good air con specialist for a full test.

I recently bought a 55 plate Renault Grand Scenic with the 1.9DCi 130bhp engine. I have seen adverts about electronic boxes that when plugged into the engine management system claim to boost power, torque and improve fuel consumption. Do they work and what effect do they have on the life of an engine? I appreciate that there would be implications for warranties and insurance. Paul Mitchell, Chorley

Your These devices generally try to fool the engine management computer into “thinking” the engine is colder than normal, so it injects extra fuel - rather like having an old fashioned choke partly out. You may get extra power (or at least, you may feel that you have extra power) but it will almost certainly come at the expense of increased fuel consumption, increased pollution and, as you point out, an invalid warranty and expensive insurance. The engine will be running on an air/fuel mixture it isn’t set up for, so the emissions equipment will be working hard to cope. By emissions equipment I mean those longer lasting (and rather expensive) things like the exhaust, catalytic converter, particle filter and so on. They’re generally OK for 100,000 miles or more these days, but if you fit one of these boxes, expect to start replacing them at MOT time when the car fails the emissions test.

If you want some extra performance, my best advice is to trade up to a more powerful car on which you’ll have a valid warranty, normal price insurance, decent resale value and sensible running costs.