Yes RUM, I remember the stories about plastic impellors too. Strangely perhaps, I haven't actually run into the
problem on VAG products but that may be because we've never owned one with the small petrol engine. My own Cordoba had a pump driven separately by the fan belt and our PD's never gave any problems. I didn't tackle my boy's 1.6 CR Fabia, leaving it to the lads at AVW. I do have considerable experience with the FIAT FIRE engines and they have plastic impellors on a cam belt driven setup. These pumps do suffer failed bearings, but no more than any other. Haven't come across one with an impellor
problem yet. The ones I fitted to our Panda and Punto, about 2 years ago, were Gates kits (my favoured brand) and both had plastic impellors. Personally I'd never do a cam belt without changing the water pump too - on an engine where the water pump is in the belt train - unless I knew the pump had been renewed very recent to the belt change. Thinking back to my time on the
shop floor, I didn't encounter ruined engines due to cam belt problems very often but I think they have got such a bad name because the outcome when one does let go is invariably quite spectacularly expensive! I feel very fortunate that our wee Panda has a "non interference" engine so if the belt lets go all that happens is the engine looses power and the car rolls to a stop. You just have to hope you're not in the fast lane at the time! Take it home, fit new belt kit and drive on. Diagnosing one where the impellor has come loose on the shaft must be difficult if you are not aware of the possibility.
Sitting at traffic lights listening to the protesting whine of an over tightened cambelt used to be a favourite pass time of mine not all that long ago. You very rarely hear that now though, probably due to spring loaded automatic tensioners now being used on most applications but also just that people got used to adjusting these belts correctly? Another favourite of mine is sitting at the top of the Mound or Abbey mount (where it crosses Regent road) both steep slopes, with the smell of burning clutch lining coming off the car in front as it's owner holds it on the clutch for a full change of the lights!
I've been looking into the fuel filters and it would seem they are available on line from a number of sources. Interestingly it seems to contain a pressure regulator on the inlet side. If you look at the filter it has 2 pipes on the inlet side and one on the "supply to engine" side. My guess, looking at the one on mine, is that the fuel is being regulated by a spring loaded diaphragm of some type with excess pressure being returned to the tank. The fuel at regulated pressure then travels through the filter element and out the other side through the outlet pipe and on to the engine. I've read a couple of warnings that you need to be very sure to get the right filter as the regulator pressure varies with application (I think the filter is used on several models/makes and pressures can differ depending). One of the tales I read was from someone who had fitted a filter he bought on line thinking it to be correct, but the engine didn't run well, even miss firing under load at higher revs. He later discovered that, although the physical dimensions were identical to the one he removed, the delivery pressure was down. I read another post to the effect that VAG themselves have slightly increased the pressure over the original fitment because of problems like this. So it would seem important to be sure you are buying not only the exact correct filter but also a reasonably newly manufactured one? Buying from the supplier here on our site - can't remember the name - who is also a supplier of Honda parts might be the way to go on this I think?
Changing the filter looks, on the face of it, to be a very simple task but I'm "bothered" by the tales of people breaking the "squeeze clips" and then having to replace the whole fuel line because the connectors are not replaceable on their own. It really can't be that hard though can it? I'm trying to build up my confidence to have a go myself! Might pop into AVW and get their take on it but their setup is much more professional now with a front reception office and it's more difficult to catch a "spanner wielder" for a quick ask.
PS added. I just remembered you mentioning the tensioner and
guide roller
problem. I think this was actually more of a
problem than the water pumps if I'm right? They'd been making them out of metal, then changed to making the part that runs against the belt to plastic and they were breaking up with predictable results. As most of these are now plastic on many makes, I'm guessing they solved that one?