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2.5TDi Plastic Turbo Inlet Pipe Fix How-To (MAF to Turbo)

55K views 62 replies 31 participants last post by  shankalanks 
#1 · (Edited)
It seems to be a common problem that the plastic pipe that goes from the MAF to the Turbo expands due to heat/oil on the end that connects to the turbo, allowing unmetered air through the intake, I bet the majority of 2.5's are like this.

If this part is replaced it will before long expand again and allow unmetered air back in.

I had a look at mine today and it was very loose!, you could clearly see there was no seal as the crankcase breather is close to the end of the pipe and there was a trace of oil past the O ring on the turbo and at the end of the pipe, as it was heat that caused it to expand in the first place we will use heat to our advantage and fix it.

To repair this you will need the following parts:

1x 10mm & 7mm socket, ratchet & screwdriver that can accept sockets.
1x Molegrips or spring clip removal tool.
1x Glass jug (Not the other halfs best cooking gear!)
1x Kettle.
1x 50mm Juilblee clip.
1x New O ring from VW that sits on the turbo to seal the plastic pipe (I didn't use one as mine was fine, so will update post with a part number)

First remove the flexible pipe from the MAF to the plastic pipe by using a pair of molegrips to squeeze the spring clip or use a spring clip removal tool, I removed the pipe on the MAF and on the plastic pipe to gain more room.

Once that is out of the way remove the crankcase breather pipe from the top right of the plastic pipe and also remove the vacuum pipe behind it.

Have a feel of the plastic pipe and see if there is side to side/up and down movement, I bet it moves a fair bit!.

Going back to the front of the plastic pipe there is a 10mm bolt that holds the pipe and dipstick to the engine, remove this with a small 10mm socket, I used a bendy adaptor as it's a tight fit.

Once this is removed you can take the plastic pipe off the turbo, inspect rubber O ring and clean turbo/plastic pipe if needed.

Now go inside the house, fill your kettle up and set it to boil. While the kettle is boiling find a suitable container such as a glass bowl or jug, I used a pyrex measuring jug.

Put a 50mm jubilee clip on the end of the plastic pipe that connects to the turbo, make sure the 7mm bolt on the clip is facing the rear of the plastic pipe as per picture 1, nip it up slightly so it doesn't fall off but can't be moved if needed with a small bit of force

Once the kettle is boiled, fill the suitable container up with boiling hot water, never mind making a tea/coffee we don't have time just yet!.

Submerge the plastic pipe with the jubilee clip in the hot water and take this outside, be carefull!!, the hot water will allow the plastic to become soft, once it's been in there for a minute or two, take the pipe off and quickly put it on the turbo, ideally you need to get the bolt that secures the plastic pipe/dipstick to the engine in loosely to align it, if you can't get it in or don't have an assistant use a skinny screwdriver to locate the holes for now and leave it there till you are ready to bolt it up.

Once in place use a 7mm socket, extension bar and a screwdriver that takes sockets to tighten the jubilee clip, nip this up tight enough but do not overtighten it. The hot water allows the plastic to be plyable and the jubilee clip will shrink this down to the correct size, this should never expand with heat and work loose again!.

Connect the vacuum pipe up and then connect the crankcase breather hose back up.
Fit the pipe from the MAF to the Plastic pipe, put the metal clips back in the correct place.

Now you can make yourself a cuppa!




 
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#10 ·
I just did this mod. You're tightening against metal so you can keep tightening I guess until just before the clip feels like it might fail. One thing I would add to this is that the next time you get the engine fully hot, you can go back and tighten the clip up a little more.
 
#16 ·
The reply above has confused me!! Just to clarify... Are we fitting the jubilee clip for good or just using the jubilee to reduce the diameter but refitting the plastic pipe as was?

If the latter than it won't be tightened against metal so what is the target inside diameter?

Thanks
 
#12 ·
Bloody hell that video looks extreme!! Checked mine today and sure enough there is play! No where near as much as that vid mind!
Think a new o ring might sort mine. Just a thought, the turbo gets extremely hot and so its fair assume it will expand and contract. If the connections to it are either too tight or to rigid then this may stress the body of the turbo.

Just thinking out loud really but Vw design is push fit with o ring on inlet (pipe will naturally be suck towards turbo), and spring clip on pressure side. Both of these suggest expansion is expected!?
 
#13 ·
It's just a simple case of poor material choice for the pipe - it has too much memory and not enough elasticity, hence each time it expands, it doesn't quite contract eh same amount which through every heat cycle makes the problem a little worse.

I think mine is beyond saying and a new pipe and o-ring will be the best course of action.
 
#14 ·
Right then - lets try the old hot water trick.

The loose fit measurement...





On with a sturdy hose clamp, tightened fair old bit...





In to a jug of boiling water for 5 mins, removing it to tighten the jubilee clamp a few turns every 60 seconds...





After a quick 'quench' in a jug of cold water, it was out with the callipers again...





<grabs torch and flip flops and heads off outside>
 
#33 ·
Hi, did you ever sort out your turbo noise? Only asking as mine whines loudly when spooling which was there when I bought the van several months ago, but is one really beginning to grate on me.

Checked all pipes and connections but can't find any issues. The noise is definitely coming from the turbo area, but no play in the spindle :*

Cheers
 
#23 ·
Sorry, I re-read my (drunken) response.. the inlet side was perfect, I was just illustrating how in hot that got and didn't cause problems (the crack is on the exhaust side). If you are worried about the pressure on the inlet you could secure it with one of those large Nylock cable ties (or 2)
 
#28 ·
Ive just taken mine off to do the EGR cleanup and blanking and just noticed how loose the plastic turbo inlet pipe is(mine was looser than a loose thing)so went to the local hardware shop(not many of them about now)and got a slightly thicker "O" ring,slotted it on and the pipe doesnt even need a jubilee clip because its a nice tight fit...EVERYONE SHOULD CHECK THEIR TURBO INLET PIPE FOR LOOSENESS!!I havent rebuilt it yet but im sure that "O" ring is there for a purpose(not to let air past)..The thickness of the new "O" ring is 3.5mm (the old one was 3mm) and the inside diameter is 43mm.
 
#29 ·
I have just found this thread by pure chance so armed with all the excellent info above I popped out to check the Caravelle - yep, you guessed it mine is loose too! I live in France and VW here never have any spares in stock so I want to order in a new O ring before taking all this to bits - don''t want to have to do it twice. Does anyone by chance know the part number for the O ring? Cheers in advance.T:
 
#30 ·
I think I have found it. Just incase anyone else wants the same numbers this is what I have found elsewhere on the forum:

O Ring: 030121119
Suction Hose: 074129715F

Mind you having just done a search for them it seems like they a VW dealer only part. You can buy used pipes but the chances are they they will be as equally knackered!
 
#32 ·
Ok done mine. It made no difference to the running as it was sweeeeeet anyway :D It was a right old fiddle to do the job though. I could not shrink my pipe enough so I put a new O ring in the groove on the turbo then put the original O ring back on as well and that did the job nicely.

One thing I did notice though was that the pipe on my 1.9TD has a jubilee clip securing it to the turbo and that is how it was fitted in the factory. I didn't need to use a jubilee clip as mine was tight with the two O rings but as they are fitted as standard to the 1.9TD I cannot see what harm a jubilee clip will do on a 2.5TDi if you want to use one.
 
#35 ·
Just done this on mine and I'm just having a well earned rest and coffee before I go out to give it a run.
I used a new pipe and o-ring and had decided to put a jubilee clip on the new pipe, just pinched up enough to stop it expanding.
It was mega fiddly, especially refitting the 10mm bolt that holds the pipe and the dipstick to the engine.
Interestingly, although the pipe was wobbly, when I got it out I discovered that someone had previously tried the fix and under the grime was a jubilee clip with the screw around the back out of sight.
They'd obviously not done the hot water shrink first though because there was plenty of wobble still and the jubilee clip was fairly tight. They'd also put a jubilee clip around the breather pipe where it connects to the inlet pipe close to the turbo so they'd obviously had a leak diagnosed and were trying everything they could think of to sort it.
I decided to fit a new breather hose while I was at it. They're cheap aren't they? (Not).
 
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