Email Tim with your questions

I own a focus st2, when i start the engine it revs to 2000 rpm then comes back to idle. I am concerned about the engine revving so much when its cold ie lack of oil at the cams. My dealer says this is normal, I am an ex AA patrol and given your technical experience would you expect the high rev at start normal, I worry that the engine will be damaged.

Philip Chisholm, Melrose, UK

These engines do sound as if they’re revving too fast for a couple of seconds after starting, but it is quite normal, so your dealer isn’t trying to pull the wool over your eyes. Since the engine speed drop straight away, the idle speed control is clearly working. The oil will be either semi synthetic or fully synthetic and because it stays very thin at low temperatures, it will get round the engine very quickly on starting, however cold it is. The main mystery is why these engines are set to rev like this on start up. My guess is that the combination of a cold engine when everything’s tight and the fact that it’s very high compression for a petrol motor, give a very high mechanical resistance and for the first few seconds it needs to run at quite a high speed just to overcome that resistance and keep running. By the way, I do remember you as an AA Patrol attending some of the courses I used to run when I was an instructor in Scotland. Now there are some tales that could be told…

Hi, I have a 1998 Renault Laguna RT sport automatic. When I start the car at the beginning of the day and pull away you can hear a loud sucking noise from the engine bay (it almost sounds like oil being sucked through pipes), then within a mile of travel the gearbox 'clunks' and you only have minimal drive power. Also the auto transmission warning light comes on. The handbook says this indicates an electric or electronic fault. but as soon as I switch the engine off and then on again every thing is fine for the rest of the day. It only happens on the first start up of the day. Apart from this first start problem the engine, gearbox and electrics are fine. Even though the gearbox is a sealed for life box could low oil cause this? As there is evidence under the engine that there could possibly be a very minor oil weep and possibly from the gearbox. The sucking sound I mentioned earlier is only present until the gearbox 'clunk' happens, on re-start it quickly decreases and goes away. I know I should go to a Renault garage to get it looked at but I fear the cost would be more than I can afford. I am quite competent with car and motorcycle maintenance, having completely rebuilt both from scratch in my time, but automatic gearboxes are to me what a computer would have been to early cave men! basically I need to know if the problem is terminal, (meaning for me too expensive to sort out) or if the problem can be resolved without involving expensive garages. any advice or info' would be very much appreciated. thanks,

Steve Knight, Dover, UK

This could be one of a few things, but all of them need to be checked by a garage that does know automatics. If you’re not fond of dealers, look for an automatic transmission specialist. The wonderfully named FATE (Federation of Automatic Transmission Engineers) is the industry body and will give you the name of their closest member. Go to: http://www.fedauto.co.uk/memfind.htm

Starting with the simplest possibility, which is also the cheapest to cure, the gearbox could simply be low on oil. In most auto gearboxes, the oil doesn’t just lubricate – it’s also the fluid that operates the gear changes and transmits the drive from the engine to the gears. No auto box is actually sealed for life, it’s just that lots of them have to go to a garage to have the oil checked, changed or topped up. This might sound as if the manufacturer is deliberately trying to make life difficult (and being Renault, you could be forgiven for thinking so), but there is actually a good reason for needing a bit of expertise. That’s because the oil expands quite a lot as it heats up – and it does get very hot. So, the level needs to be measured alongside the temperature of the oil. Get the car to someone who knows how to check it – and keep your fingers crossed, because if it isn’t simply low on oil, the next two problems are probably terminal for a 10 year old Laguna. These ‘boxes are prone to two major faults. The first and second gear brake band fails (that’s the device that changes between the two gears) or engine coolant can leak into the gearbox oil cooler and mix with the oil. Either of these is probably an uneconomic repair for the ‘box itself, so you could look for a second-hand unit from one of the online parts brokers such as www.breakeryard.com

I have a Xsara Picasso 1.6 sx 52 reg. when driving the headlights come on by themselves, when I touch the stalk that controls the lights the lights go off, but if I move the stalk slightly the problem does not return. Could you please tell me if the light stalk is broken or is there an electrical socket loose. Thanks

Name and address withheld

This is not a known problem although Xsara electrics are not brilliant. From your description I think the stalk itself is the most likely cause – another ideal part to source second-hand from the online parts broker such as www.breakerlink.com or www.find-a-part.com (as you can see, there are quite a few of them and I’m trying to avoid implying that I recommending any specific one!)

Hi Tim

I hope you can help.

I am getting what can best be described as a growling noise from the transmission area. I have had gearbox specialist review, strip and replace the bearings and they have informed me there is nothing wrong with the gearbox, which then leads me (and them) to suspect the clutch.

The noise is only heard on the over-run when changing down the gears, so would really appreciate your advice on what you think the problem could be?

Car - Honda S2000 (2001)

Thanks

Name and address withheld

Why on earth didn’t the gearbox specialist examine the clutch when the gearbox was off? I would be having words. However, if the noise is only apparent on overrun, it could be the differential rather than the clutch – or a dodgy engine/gearbox mounting leading to body contact. The driveshafts and couplings are worth a close look as well.

Apart from looks and more rubber on the road what are the pros and cons of fitting larger wheels on cars?

John Gray, Rotherham, UK

The advantage doesn’t come from the larger wheels, it comes from the lower profile tyres that you fit on them. The rubber in a tyre wall is flexible and idea is that the less flexing there is between the wheel and the road, the more positive the steering and handling is. The low profile tyres have shorter tyre walls, which are therefore more rigid. Steering response is reputedly enhanced. However, higher profile, more flexible tyres are much better at absorbing bumps, so if you do feel the need for even greater precision than modern cars give you anyway, be prepared for a bumpy ride. The extreme examples that look like a huge wheel with black paint round the rim will shake the fillings out of your teeth. You need to match the tyre size to the wheel size so that you keep the combined diameter of the wheel and tyre the same (or almost the same) otherwise you may foul the bodywork or suspension and your speedometer will be inaccurate, and possibly illegal. You don’t necessarily need to fit new wheels to fit lower profile tyres – for example, on a 13 inch wheel, 165/65, 175/60 and 195/55 tyres all have the same overall diameter and you will probably notice a difference between the first and last, although you do need to check that the wheel is capable of taking the tyre. A good tyre distributor will have charts to show you the allowable range of wheels and tyres you can fit.

I found this module on ebay (http://stores.ebay.co.uk/High-Performance-Modifications) which claims to increase bhp + torque, no increase in mpg and 100% safe. Can be fitted in 5 mins and removed in 1 min. Only cost £6.50 including delivery.

Very tempted to fit one on my 57 plate Skoda Octavia 1.6FSI and remove it before taking it back to dealer for service etc. Can the technicians tell from the car's computer record that it's been altered/chipped before?

Of course the seller won't advertise any potential problem. What do you reckon?

Name and address withheld

This isn’t a “Chip”, it’s simply a resistor – the sort you can buy for a few pence from an electronics store. However, it is installed in a fancy box and it does come with instructions. The instructions will tell you how to substitute it for the air temperature sensor so you feed incorrect information to the engine management computer. It will “think” the air is colder than it really is and this will make it inject more fuel than it should. So you MAY get a richer mixture, as the advert claims, although the management system may well correct it instantly back to normal, in which case it will have no effect – that’s the whole point of the oxygen sensor. If you do get a richer mixture it will give a slight increase in power and torque which might be enough for you to notice, although cleaning and re-gapping the spark plugs will probably do about the same. The claim that the device will protect the engine is complete nonsense. Claims about increased economy are also nonsense. You are “fooling” the computer into injecting more fuel. That does not use less fuel. The people who report a fuel saving are victims of the placebo effect – injecting more fuel means you use more fuel, however much people have convinced themselves otherwise. Other possibilities are increased emissions that will make the car illegal to use, and because of the increased hydrocarbon emissions from the cylinders you run a risk of ruining the catalytic converter. How likely or serious these effects are depends on how effective the device is. The more it lives up to its claims about giving more power, the more serious the consequences will be. You can’t get away from it – it’s how engines work.

To answer your specific questions, if it’s removed for MOT or servicing, in most cases there will be no evidence left in the computer to inform on you. However, on some cars, including some Audis which share engines with your Skoda, the computer detects a fault, lights the “engine check” warning lamp and records the problem. Of course, if the catalytic converter has deteriorated to any extent, you’ll fail the MOT emissions check which will land you with a large bill anyway, so whether they know you’ve had the device on or not is a bit academic.

In case you haven’t already guessed my answer to your second question, I reckon you should keep your £6. Sadly, nothing I say will put this seller or any of the other parasites out of business because there will always be people who believe in magic rather than facts and who are prepared to pay to prove themselves right. I would call them gullible – they would call me cynical. It’s a lot cheaper being cynical!

If you want a technical explanation of why these particular devices are a complete con, click here

I have a 52 plate volvo S80 diesel which has done 92000 mls, i have noticed that when i accelerate clouds of black smoke come from the exhaust pipe.can you please advise.many thanks

James Austin, Rugby, UK

If this has happened gradually, over a period of months, it’s probably due to worn or dirty injectors. The best cure would be an injector service from a specialist, but for a lower cost option, try 2 tankfulls of Shell V Power or BP Ultimate. The high detergent content will clean the injectors and improve their performance. If it starts to improve keep using the good stuff for a while, then repeat it every so often.

If, on the other hand, this has happened suddenly and you’ve also noticed a drop in power, get the EGR valve checked. EGR (Exhaust Gas Recirculation) valves are fitted to most diesel engines these days to reduce the smog forming emissions called NOx. However, they exist is a pretty hostile environment and they can get chokes with sooty deposits and stick open or closed. They can sometimes be cleaned as a temporary cure but a new unit is the only permanent solution.

I recently bought a new manual Volvo V50 T5 Sport and although very pleased with the car in my opinion it suffers from transmission shunt. When travelling slowly in traffic changing from 1st to 2nd to 3rd and then down again there is a pronounced 'clunk' when the drive is taken up. The dealership have test driven the car and say it's common to all six speed gearboxes on the V50 and nothing more than 'gearbox slap'. Is this true ?

Phil Lewis, Cardiff, UK

If the dealer says it’s the same on all of them ask for a test drive in another one so they can prove it. If the other one doesn’t have the same “slap” tell them to fix it. If they don’t have another one to show you, tell them to get one from another dealer and let you know when it’s arrived. You’ve paid a lot of money – don’t be fobbed off.

I just bought an 05 reg (late 05) Fiat Punto Active Sport 1.2 8v. The car has only 13,000 on the clock and is in fantastic condition inside and out. The car is coloured bright yellow, however the only problem is that the small spoiler on the rear of the car (at the top of the rear window) is a slightly duller yellow than the rest of the car; it looks to me like slight discolouration (although I'm neither an expert on cars or paint!) it is quite noticeable and it is definitely the original spoiler. The car still has one month left on the manufacturers warranty and I took out a years extended warranty with the RAC. Is this a common problem and would this be an easy thing to replace / sort out given the cars warranty?!

Owen Marsh, Newport, Wales

The spoiler will be plastic, not metal like the body. A bright paint like yellow is prone to showing the differences in the underlying surface smoothness and as it fades at a different rate. Not too much you can do, but it might be worth trying to get a new spoiler out of them.

Hi Tim,

I bought my Vauxhall Zafia 4 years ago from a Vauxhall dealer, now having problems with the timing chain and tensioner. I did some research and found that this is/was a common problem and a manufacturing fault. Although my car was not on any re-call list I found out that just prior to me receiving this car the timing chain and tensioner were both replaced but NOT the oil nozzle. I understand that the original oil nozzle was undersized and this resulted in insufficient lubrication of the timing chain hence why they where failing and why, I believe, it has failed again and damaged various valves. My Vauxhall Garage have stated that they do not know why this wasn't changed at the same time. Therefore do you believe I should get a independent engineer to do a vehicle inspection to ascertain if this is the reason I am now faced with a possible repair bill of £2000.

Your advice would be very much appreciated.

Kind regards

Gina Beston, UK

You are broadly right about the nozzle, although the full story is slightly more complicated. The actual problem (according to Vauxhall) was not that the nozzle was too small, it was that the hole could get blocked by sludge caused by poor quality oil or infrequent oil changes. Evidence of proper oil changes done on time will therefore be very helpful. They did fit a larger nozzle to these engines from early 2002, but as far as I know they never publicly accepted that the original nozzle was inadequate – otherwise they would have had to recall all the cars with that engine and modify them – and the majority will work perfectly well for the life of the car.

My advice therefore depends on whether you have a full service history. If you have, write to Vauxhall Customer Relations, explaining that all servicing, including oil changes, was done on time with approved parts. Tell them what has happened, point out that the nozzle should have been changed when the timing chain was replaced last time and ask if they will consider paying for the repairs. Please be polite though – the car is long out of warranty and they are under no legal obligation to do anything. If you don’t have a full service history it will be much more difficult to persuade them to contribute, since they can point to the fact that lack of oil changes can be the cause of the problem.

Hi Tim,

I reside in Jakarta, Indonesia. I own a Peugeot 307 SW (known as Estate Wagon anywhere else), manufactured in 2004. I recently have problem with starting the car in the morning and whenever the engine is switched off for more than 30 minutes. Whenever I turn the ignition key, the starter motor keeps whining, for about 3 or 4 seconds longer than normal, before the engine kicks in.

I have brought the car to Dealership's garage and still have the same problem. What they did was checked the potentiometer on the body throttle, told me it could be malfunctioning and replaced the unit, even though the computer they hooked up to the car CPU terminal did not report any faults.

They also flashed the CPU and yet I still have the same problem.

I was wondering if you could shed some lights over this matter.

Pardon my grammar and spellings, as I haven't used much english since I got back

Name and address withheld

1) Your grammar and spelling are both great – better than many Brits.

2) Peugeot call their estates SW everywhere

3) Indonesian dealers don’t seem any better than UK ones! This problem is almost certainly the coolant temperature sensor. It tells the computer (or CPU) that the engine’s cold and it will need extra fuel to get it started. If it’s just giving inaccurate readings, rather than having packed up altogether, it won’t necessarily show up as a fault report on the diagnostic computer. It’s a simple and inexpensive job to do.

Hi Tim,

I am wondering if you can help. I have a Zafira 1.8 Elegance Reg 51. We drove to France last month (c. 600 miles) and the day after our arrival when we started the car again the power steering had gone. We checked the fluid and it seems to be ok.

We went to two garages (I am trying to stay clear from the Vauxhall dealership). They looked at it and said it was an electrical problem. I called a mobile electrical engineer who came and tested the car. He diagnosed that the Power steering pump needed to be changed. He located a second hand pump and is prepared to change it on the kerbside for us for about £300.

My father-in-law went to Vauxhall garage and was told that the pump is actually part of the Power steering rack and that actually the entire rack would need changing (a cost of about £1,100 as its about one day of work). I don't know who to trust... any views on the question?

Thanks for your help, Best regards

Lionel Guerraz, London, UK

The workshop manual describes replacing the pump as a separate operation so go for your friendly electrical chap.

Dear Car Clinic

I would be most grateful if you could suggest a solution to overcome the following problem:

Using the screen washer results in a nasty stagnant water smell in the car. I have flushed the washer system out many times, used different screen washes, even filled up with different types of water but still the smell returns. I assume the washer system is contaminated but I am at a loss to know how to get rid of it.

Regards

Harold Biggs, Stafford, UK

I have to confess that this was a new one on me, but an esteemed colleague came up with the answer straight away. She tells me you need some Puriclean tablets – add these to washer bottle and they will disinfect the whole system without causing any damage (unlike bleach). This is the sort of thing used by caravanners/motor home users.

Try this