Hi Guys,
My 82k Mk5 runs great - however I had noticed a marginal drop off in performance over past 5k miles. Wasn't enough to cheese me off but noticed it all the same.
I subsequently did all the usual things - changes plugs, injector cleaner, Shell Petrol etc etc.
Anyway, I was under the car a few days ago for a check over and noticed that the rubber Intercooler pipes, where they connect to the Intercooler with Spring clips were a bit grubby with what looked like oil. I disconnected the clips and the pipes came off so easy - meaning the sealing rings were well and truly past there best.
Ordered new seals (3 rubber rings) from VW and cleaned all the pipes and put them all back together today and took car out for a test drive.
Amazing - the difference in performance is really there and noticeable - engine feels more boost now and stronger in the mid-range.
Clearly these sealing rings had perished over time and were leaking boost. My car is standard and very well cared for - clearly these are not a usual service part.
So guys - have a look under your car - remove the front splash tray helps and check you intercooler pipe connections...
May be the best £10 for 3 new seals you have spent with VW ! How many other Mk5's are out there with this problem me thinks.
Also i have to question how VW could engineer such poor connections - they are clearly prone to failing with that Clip on design.