Scirocco Register

Hey folks

I've convinced myself that my poor idling / dodgy exhaust note issue is down to an air leak somewhere in the system, so i've decided to start by replacing the vacuum hoses.

So far i've had no look trying to find a kit to do this, so i'm going to get some appropriate hosing and do it myself.

The problem is that despite much googling of the issue, i can't find any info on what diameter piping i'm going to need, or any kind of diagram showing the layout to make sure i don't miss anything.

The car is a 88 GTX running a completely standard DX engine.

Can anyone help?

Mk1autohaus shop on ebay will show you some of the layout diagrams, as he sells replacement silicone vacuum hoses.

I re-did my vacuum hoses recently with stuff from GSF, this link shows the stuff.. http://www.gsfcarparts.com/186aa2010

I found 2 meters was exactly right for a carb'd car, 'fraid I'm not sure how much you'd need for injection?:dunno: but for £1.50 a meter it'd be safe to assume that 3 meters will be more than enough and it still comes in under a 5er!

Can't help you with the layout either but if you replace the old hoses one at a time then at least you'll know the layout is the same as it was with the old hoses. This way if you see a difference with the new hoses and the old layout you've narrowed it down to the old stuff being deteriorated, but if you don't see any difference then you can suspect the layout is wrong.
Of course the above assumes that there are no other issues, for example if there was an issue with cam timing/spark timing/spark strength/compression/fuel delivery/bad earths/TTV/CTS or any other component failure then all the messing with vac hoses in the world won't sort it..

Let us know how you get on!


***EDIT*** I just had a thought - have you tried spraying carb cleaner at the areas you suspect are leaking? If the idle changes when you spray X component you found your leak!

Replaced loads of vacumn hoses, not just my own, usually at shows as always have a metre or so in my famous toolbag!
As said, best way is to remove the old hoses one by one, measure next to a new length and replace.

If you wanted a diagram of your hoses ask your dealer, I have had no problems getting dealers to print out from ETKA, or even email me a diagram. The diagram shows part numbers and lengths that the hoses need to be shortened to.

Most hoses I have replaced have been totally knackered, as they are usually overlooked!

Thanks for the help guys, called VW and they sent me the layout, complete with lengths and part numbers!

As for the replacement hose, can't access ebay from work to check the prices, but i'm guessing the silicone hoses are a fair bit more than the standard rubber - is it worth the extra expense?

Thanks for the other idea's Nick - the thought behind it being a vac leak is that it's making the same wierd exhaust note as my GT2 used to make when my inlet gasket failed (Kind of a Put-Put-Put - sounds like i'm driving a beetle, but occasionally it sounds fine and idles at the correct speed)
i've sprayed this area liberally with carb cleaner, but there was no change, so figured that as the hoses are all 20+ years old, and i dont want to spray the entire engine bay with carb cleaner, this would be the next (and easiest) place to start.
At this age, i'm guessuing they're going to fail sooner or later, and at least its one less thing to worry about!

Not worth just changing some, for the minimal cost it is sensible to do the lot.

i meant the extra expense of silicone hoses vs the standard rubber ones, but now i'm back home i see that there's really not a lot of difference in price either way for generic hoses (though Mk1 autohaus ones look really good,a full set of those would be more than i paid for the car!)

Here's the layout diagram VW sent me incase everyone else needs it: