tim-spam

A similar thing happened to mine and the cause was the spanner monkeys at the dealer not having re-fitted it properly after replacing a chafed water hose, which had chafed against the fuel filter which said spanner monkeys had left hanging by the hoses. As the car was just out of warranty, I refitted everything properly and all has been OK since. There is absolutely nothing wrong with the design - your problem will have been caused by incorrect fitting or damage, probably at the dealers.

An early 2.0 Ford engine will not have the freewheel alternator pulley.

If it's a Mk2 Galaxy with a VW Group diesel with just a simple sprung tensioner, it will have a freewheel pulley. Another way to check is to look if there's a 'lever off' plastic cap in the centre of the pulley.

This is only true for spark ignition engines, which includes those fuelled by petrol. The reason is that the pumping losses associated with operating at part throttle on a petrol engine reduce engine efficiency. These pumping losses are caused by the throttle butterfly in the intake restricting the amount of air being drawn into the cylinders. On a compression ignition engine, there is no throttle butterfly, and the consequent lower pumping losses is one of the things that contributes to the better efficiency of a diesel engine over a petrol engine. In other words a diesel runs permanently with a wide open throttle. This is also one of the reasons why turbochargers work so well with diesels.

Putting sensors on one side only is a good, cost effective design - absolutely no need to have them on both sides. You do not have to disturb the metal pipe - I know because I've done it. If you quote the year and engine type to either a dealer or a good motor factor such as Eurocarparts, they can supply the right pads. The fact that your motor factors have the wrong information in their books is probably not the fault of the manufacturer.

Head gasket?

But remember that automatics consume more fuel. On mine, I get between 37 and 43mpg depending on use - overall average is between 38 and 39mpg. But mine has the 6-speed manual gearbox - I would expect an automatic to be at least 10% worse. The only exception to this is the VAG DSG gearbox, which matches a manual for both performance and economy (in fact, the acceleration figures are slightly better due to the faster gearchange), but this will only be available on the next generation Sharan.

The metal thickness has not been reduced.

Probably copied, illegal and with no support.

What I should have said is that he got over 65mpg over a whole week's driving. Perhaps I should also have said is that his car is a Skoda Fabia 1.4 TDI.

Well, just to put the cat amongst the pigeons, my brother-in-law has just achieved over 65mpg in his TDI....

If we assume he bought the most expensive diesel and gets an extra tenner's worth by 'burping', that would mean around 80 litres in the tank (still a little doubtful, but let's continue anyway). The fuel light comes on with around 7 litres left, which would then equate to 1188 miles on 73 litres. This means he claims to have achieved around 74mpg - hmmmmm. However, if the odometer is reading in km instead of miles, this would mean he achieved around 46mpg, which is quite likely for a gently driven TDI. Perhaps a quick session with VAGCOM to reset the odometer to miles is in order.....

Although replacing the N75 valve and/or TMAP sensor are usually tried first by the dealers, I have never yet heard of a case where replacing these parts has cured an overboost problem. As regards the VNT, this is designed to operate without lubrication. Should you use grease or oil on the internal bits after a strip down and clean, this could well lead to it sticking again, due to the deposits left after the oil or grease is burnt off (which it will be due to the high temperature in the turbo). So, if you decide to strip the VNT and clean it, the internals should be assembled dry.

There are 2 'O' rings - one blue and one black. Another possibility is the joint between the fuel hose and the rear connection to the tee-piece. If the spanner monkeys have installed the filter such that this section of hose is pulled too tightly, the rear pipe section of the tee-piece can develop a permanent bend, causing a slight leak. If this is the case, you will need a new tee-piece.

Most likely cause is a sticking VNT mechanism. Does the engine feel rough and sluggish just before tripping into limp mode? If it does, that confirms that the turbo actually overboosting rather than receiving a spurious signal from the TMAP sensor. The posts so far indicate yet again how little the dealers understand. Having said that, the official cure for a sticking VNT mechanism is indeed to replace the turbo - expensive. However, there is an excellent thread (started by dt1) on how to clean the VNT mechanism. Another alternative is to manually give the mechanism some exercise to try and free it up.

The battery really should be properly clamped down to prevent movement and the consequential fire risk, quite apart from the possible fatigue failure of the main battery leads. If the clamp is missing, I shouldn't think that it would be an expensive item to replace.

I know you've had the MAF replaced, but it does sound like the MAF is not working properly. Does your car accelerate well as you press the accelerator, but then hesitate at around 2000rpm? If you release the accelerator and then press it down again, does the car accelerate well and then pause again once the accelerator reaches the floor? Is the problem more noticeable in the higher gears? If the answer to all of the above questions is yes, then that would point to a MAF on its way out - are you sure that the MAF was actually replaced?

Maybe, but until you actually examine the car properly, you can't really tell......

Either will do. Engine code is AUY.

MAF's tend to start failing at a 60,000+ miles. Cheap (around

If the tensioner has failed, this may have been caused by the alternator pulley having failed. This should be checked first, as the tensioner may actually be OK.

Chains are usually designed for the life of the engine, but should it get noisy, it should be replaced together with the tensioner components. If the sprockets are also worn, it would be a good idea to replace these as well. Failing to change a noisy cam chain could well lead to it defining the life of the engine. On my wife's Mercedes, I replaced the chain, tensioner rail, tensioner and guides at just over 200,000 miles (the sprockets were OK) due to noise. When I took off the cam cover, it was possible to lift the chain away from the cam sprocket slightly, indicating significant wear in the chain. However, if all is quiet, leave well alone.

If a cambelt snaps, the damage is usually very serious, and a new engine may be required. If a cam chain snaps, a new engine will be required. However, the advantage of a cam chain is that it gets noisy before it fails, whereas a belt can stay virtually silent until it snaps. There is no problem with either system so long as the belt and rollers are replaced at the specified intervals or the chain (and tensioner) is replaced when worn.

Nice car.

Is it the alternator drive belt tensioner by any chance? This is a spring loaded arm with a pulley pressing against the outside of the belt. If this is worn, it can become noisy - alternatively, it could be the alternator pulley itself causing the problem. These pulleys have a one-way clutch in them, and this is used to damp out the vibrations in the belt drive - they can start to fail anywhere after around 60,000 miles. Another symptom can also be a chattering feeling from the power steering pump.