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Fantastic guide, many thanks, I am willing to bet at least 50p that my inlet pipe is a bit floppy, I'll pop over to TPS tomorrow and get a new o ring and if I have time I'll give it a go, endless jobs of owning a T4!
 

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Fantastic guide, many thanks, I am willing to bet at least 50p that my inlet pipe is a bit floppy, I'll pop over to TPS tomorrow and get a new o ring and if I have time I'll give it a go, endless jobs of owning a T4!
If any one took me up on that bet you owe me 50p! I replaced the O ring, it was caked in sealant, which I removed, taking care to not get any in the turbo, the pipe was still pretty baggy but definitely better than it was, so if TPS has one I may just replace it. Definitely had to do some yoga to get that bolt back in, right hand facing away from the bolt, and doing it by touch, with the constant do not drop it thought, alongside, is it in yet?

Personally I found that a flexi rachet spanner worked well for the bolt
 

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Have to congratulate Aurora on their initial post in this thread, as I decided to do it 'for a laugh' yesterday, not expecting much as there was only a couple of mm play, max.

I could hear a bit of turbo whine around 2500rpm, which I actually liked but hadn't noticed a flat-spot as such but I've been putting it off for 6 months or so. I wasn't keen on the boiling water lark so just decided to fit a 41x3.5 o-ring in the slot - didn't have anything closer in size. The actual slot is 3.5mm wide by 2.0mm deep with a diameter of 43mm.

The results are shown in the images below.

The original o-rings are 42.5x3.0 (according to parts diagrams), so are designed to stretch into place. When fitted the outside diameter of the o-ring is about 48.8mm, so you do wonder if a certain latitude was designed in as mentioned earlier. As you can see the originals are a looseish fit and may actually be more to keep the surfaces apart than act as a seal(?), and they don't look as it they've lost their shape.
184777


With a 41x3.5 o-ring we get this and the diameter is now 49.8mm. This is actually a snug fit on my vehicle but I appreciate the variance is vast and this won't suit everyone:
184778


With a 42x3.5 o-ring the diameter would be just under 50mm, and with 43x3.5 o-ring you get 50.2mm. So there's not a lot of difference but as the original was intended to stretch to fit I prefer the idea of the 42mm over the 43mm.

Next time I'm messing about under the intercooler I will fit a Viton 42x3.5mm with usual silicone grease between it and the inlet pipe. Won't bother with hot water shrinking but may put a s/s hose clamp on there.

Anyway the purpose of this post was to thank Aurora for spotting this potential problem, and the fix options, and the fact that it's a VERY OLD thread is irrelevant. Also to say that despite the tiny difference between the old and new o-rings, the actual impact on engine pick-up is astonishing, with no turbo whine kicking in as before.

A very satisfying couple of hours messing about, apart from that daft 10mm bolt of course.
 
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