My Fabia has been down on mpg for quite some time and has been whistling like a goodun for even longer.

I put the former down to short commutes in traffic and the later down to a turbo which has done almost 130k with 90k of those being remapped.

However i saw a post in another thread linking poor MPG to a boost leak.

I'm also assuming a boost leak would give a whisltely noise.

Thus explaining both the issues mentioned above.

The car was serviced recently and all was deemed fighting fit but most of my boost pipe joints have always seeped oil a bit.

Is there a way to diagnose a boost leak for sure or do i just need to chek all the joints and seals and make sure they are as tight as possible?

You can do a smoke test, which involves disconnecting the pipes at the EGR and turbo, and running them up to pressure, any leaks you'll see with smoke pouring out.

You could probably do the same with an air compressor if you have access to one if you bung the end up properly.

First port of call though would be to give each connection a proper tug to make sure that the clips aren't worn.

Hard to describe but when i had a boost leak i got a whooshing / sucking noise when the boost came in.

My old kkk used to whistle like a good un but when took off was deemed quite healthy for a turbo that had done 90k

Any noticeable black smoke on acceleration?

I've had squealing when I had a boost leak before.

Any noticeable black smoke on acceleration?

Yes plenty; although it's always been a pretty smokey remap to be honest

I agree with Joel on the sucking noise it's just before the boost sounds a bit like sucking a straw in an empty glass haha this is how I found my boost leek all sorted now and the sucking noise has gone their was also a bit oil, mine was on the 45 going into the intercooler

Shall recruit some helpful Briskodians at Combe on Saturday to have a nose/listen under the bonnet and see what we can find.

Probably be the best thing mate everyone seems to be having problems with these boost pipes absolute **** design by skoda :(

You'll know a boost leak by a hissing sound and as said if you do the smoke test you'll find it.

the pipes are crap and the metal bungs wear down after a while. when you come on and off boost they move about and wear. **** design really.

I've got a MASSIVE boost leak coming from a hole in the cooler. puffs out a lot of black smoke when i put my foot down so thats another sign. i only get about 44mpg on B roads too.

yeah mines been running at around 45mpg for months and i only ust put 2 and 2 together when i saw boost leaks and poor mileage mentioned in another thread.

It's highly likely that at least one join or seal will be knackered after 130k!

I've just spent today leak testing my boost pipes due to a similar sounding problem and I'm at a point where I'm so confused at what the issue is that I'm thinking of giving up and selling!

I was so sure I found the leak on the bottom boost pipe to the intercooler as it was hissing under air pressure..however I took it off, replaced the seal..wiggled it about and the hiss disappeared..however my awful whoosh sound still exists under acceleration!!!!!!! Frustrating!!!

there is always going to be a faint hiss or whoosh, they run high pressure (1.2 bar) so expect a bit of noise.

only be concerned if its REALLY loud.

Dont do a half arsed job. spend 10 minutes taking your bumper off and right light out to have a dig around. get someone else to help you too by revving now and then.

Check that your intercooler isnt blowing at the bottom and pipes, bottom pancake pipe to the turbo, and the upper pipes.

Dont forget the pressure box makes a slight noise too.

all else fails, smoke test.

take it to shark and get them to smoke test it

I would recommend cleaning up the oil of all the pipes and inspect after a while and look at where the oil residue has built up and come from. 

 

 

I've already gone down the route of replacing the pipework completely. The only problem is now after being a cheapskate and buying elbows off ebay I have yet another split on the elbow off the turbo. I'm currently looking at getting metal elbows and somehow running that off the turbo.