Since my last correspondence, I have bought a CitroÎn C4 CoupÈ EGS, ex-CitroÎn UK pre-registered car, for a very good price. I sold the old car as the EGS transmission was starting to become very jerky on take off, and I was advised that repairs could be costly. I cover 16,000 miles a year, hence I need a reliable car. I had also lost alot of turbo boost at up to 2,500rpm, and the front suspension wishbones needed doing, plus some new tyres, and the cost to repair this for the looming MOT would be very close to, or beyond, the trade-in value.

My old C4, a 1.6-litre HDi, used to average around 48mpg and the new C4, a 1.6 BlueHDi with the AdBlue system, now has done 6,200 miles after five months, and is delivering around 55mpg. The stop-start system appears to work well, and what I’ve also noticed is that, whilst the old C4 had a very black sooty exhaust, the new C4 exhaust tail pipe is so clean that I can put my finger up the exhaust and it comes out totally clean. My AdBlue system appears to be working well, and the supplying dealer has given me a free first service, and all the services include an AdBlue top-up. 

I was very surprised though when I saw on the GSF website that the price of a replacement battery was almost twice that of the old C4. Are there in effect two batteries, one for the stop-start and another for other requirements?

Here’s an interesting tale for your readers though. A neighbour has a petrol Vauxhall Astra which had to recently visit a paint shop. The car was driven there and then into the paint shop for appropriate spraying, apparently with electrostatic paint, but when the spray job was finished, the car refused to start. He was forced to buy a replacement ECU and the car now goes alright, but of course there are now some discussions over who is liable. The paint shop is refusing to accept liability, however, on the grape vine it would appear that there is a known problem with the this type of spraying for knocking out the ECU. I was wondering if, in your vast experience, you had heard of this problem? All the best, 

Keith of Keynsham

Well, you’ve thrown me a bit Keith by referring to your new car as a C4 CoupÈ, although there have been cars referred to as “four door coupÈs” in past times; but I do think of the C4 as a hatchback and, unless you’ve bought some odd variant that I don’t know of, I’m taking the car to be a CitroÎn C4 five-door hatchback of the latest specification.

I’m not at all surprised that you’re getting 50mpg plus, and I’m pleased that you have no problems with the AdBlue system. CitroÎn and Peugeot have wisely decided to go with this system and not tried to cut any corners with the cheaper NO_x storage systems that some manufacturers are using. As I think I’ve mentioned previously in these columns, if you need an AdBlue top-up between services, you can get one for £10 at a dealer, AdBlue, labour and VAT included. But don’t let anyone catch you stuffing your finger up the C4’s exhaust pipe Keith, or they might get some rather unhealthy ideas about you!

I have not come across the ECU failure from electrostatic painting, but it’s a very interesting story. As I’ve understood, the item to be sprayed is fed an electrostatic charge, although I’m not sure how this is done in the case of a complete car, as opposed to a body shell with no attachments. This electrostatic charge is distributed unevenly, with any sharp radius areas, like edges and bends, and nooks and crannies, attracting a higher charge density than the flat areas. The paint sprayed is also charged, with an opposite charge to the item being sprayed, to which it is then attracted, with the paint being distributed more thickly on the sharply angled areas; this, of course, is just what you want to protect such areas that are vulnerable to physical damage or corrosion. I guess that, with regard to this problem, any ECU must carry some sort of residual electrostatic charge, and that possibly means that charged fine paint particles are attracted to it, and into its nooks and crannies, with consequent damage. But the company that did the spraying is undoubtedly liable for the damage, and your neighbour should not have had to pay for the new ECU ñ no way! Tell him to go back and demand compensation!

Regarding batteries and the stop-start system, the starter will be an extra heavy duty item to withstand the more frequent use, substantially different from a standard starter, so maybe that’s why it sounds so different. The battery will also be a suitably uprated item, and thus inevitably more costly, but there will only be one battery, although probably a physically larger one than in earlier times. The only second car battery that I have ever encountered (with a vengeance!) was one for the alarm system of a Jaguar, some years back. Somebody steam-cleaned the engine compartment and set off the alarm. I’ve never seen anyone so puzzled, as when we disconnected the battery, the mind-blowingly loud alarm refused to stop blaring. I am not sure whether they ever found the second battery. It was a stressful experience, although I was not directly involved, and I think I swiftly escaped from the vicinity to protect my ringing ears.

I hope that you continue to be pleased with the C4 Keith. Always good to hear from you.

Doc Diesel