PORSCHE TECHNICAL TOPICS
Technical problems solved
I was chatting to Steve Mchale at JZM in Kings Langley, Hertfordshire, a few weeks ago, the occasion being the coffee morning he and his enthusiastic staff had organised – and which brought out no fewer than 250 people, in what must have been at least 200 Porsches of pretty much every shape and size. It was quite a sight, especially for a Sunday, with virtually the entire industrial estate full of Stuttgart's finest.
Somehow or other we got on to the subject of the rearwindow washer in Cayennes – I always like to glean some technical nugget or other from Porsche people with Steve’s long experience – and more specifically what to do if, or more likely when, it ever stops working.
‘Stop using it!’ was Steve’s characteristically simple, pithy advice. ‘And get it fixed.’ That sounds pretty obvious, of course, but there is a natural tendency among we humans to keep jabbing at any suddenly unresponsive switch or control in the usually vain hope that the problem will miraculously somehow cure itself. I did exactly the same myself last week, when the driver’s window of my Vito van wouldn’t reliably roll back up again, clearly indicating some kind of electrical rather than purely mechanical issue. (It’s now working again, as it happens, but for how long?)
It may be simply that the washer system’s fluid reservoir is empty, which is easy enough to check and rectify. What often happens, however, is that the jets block up – with either plain, old-fashioned dirt or, if you live in an area with so-called ‘hard’ water, with calcium deposits. And that is Very Bad News. Because the pump, bless it, delivers at such a relatively high pressure that something else within the system has to give. And usually it’s where the plastic pipe carrying the fluid from the front of the car to the rear meets an ‘L’-shaped connector deep within the dashboard.
Once that happens, says Steve, operating the switch squirts a hefty dose of liquid all over the massively complicated adjacent wiring (and remember that most screenwash antifreeze additives are also flammable) from where, in the fullness of time, it usually ends up inside the ECU that controls many of the car’s ‘body’ systems, such as the door locks, the window and seat motors, and not least the central-locking. You really couldn’t make it up if you tried, could you?
Repair is a time-consuming and thus costly process, adds Steve, requiring the stripping out of every last centimetre of corroded cable, and its replacement using the correct specialised connectors (which, needless to say, JZM buys in from the relevant supplier; nothing less than the best will do). Indeed, the cost can be a significant proportion of what an older Cayenne might now be worth, and while that isn’t necessarily a deterrent – if you are in that deep you often have no choice but to keep going; look at the hostages to fortune that many 996 and 997 owners have become – it surely has to hurt. Forewarned is always forearmed.
JZM’S Sunday coffee morning on 11th June was attended by more than 250 enthusiasts, in perhaps as many as 200 cars. Next event is on 1st October, offering another chance to see the company’s latest stock, tour the workshop and, if you are very lucky, bend Steve Mchale’s ear with technical queries...