1.4 tdi greenline boost leak

[Skezza]

I'm off the back of a long ish drive and about 5 mins before I arrived, the car developed a boost leak (I think). Before anyone says search, I've done searching, plenty of it. Not really found anything specific to the greenline though and what I can potentially do. 

 

The car feels underpowered (more so than usual). It whooshes in lower gears as the turbo spins (loudly if I need to get up a hill) and cuts instantly out when I change up or dump the clutch. I've checked the larger top hoses to the best of my abilities sans time, appropriate tools etc. I got under the car as best I can but my access to the lower large hoses isn't great. I've tried to check around the intercooler, everything seems ok. But clearly something isn't right. 

 

I've got to drive home around 150 miles. Obviously I can drive in a high gear at low speed but is there anything I can do to potentially budge it for the ride home? I still haven't identified the cause yet. Are there any usual suspects?

 

If I drive it home slow and under the turbo, I am hoping I'll be ok.

[Skezza]

Got the car home. Now need to start tracking down this leak. 

I've checked all of the larger hoses. Are there any smaller ones?

[sepulchrave]

1 hour ago, Skezza said:

Got the car home. Now need to start tracking down this leak. 

I've checked all of the larger hoses. Are there any smaller ones?

 

There are only two pressurised boost pipes, one from the turbo to the intercooler and the other from the intercooler to the inlet plenum on the engine so you only have four joints to test, don't use your eyes, grab the pipe and pull it hard near each joint, any movement means a leaky joint.

[Skezza]

11 hours ago, sepulchrave said:

 

There are only two pressurised boost pipes, one from the turbo to the intercooler and the other from the intercooler to the inlet plenum on the engine so you only have four joints to test, don't use your eyes, grab the pipe and pull it hard near each joint, any movement means a leaky joint.

Thank you. Tonight's sorted for me. 

 

Is it only larger hoses or smaller as well?

 

Will report back when I know more. 

Edited 29 May by Skezza

[sepulchrave]

2 hours ago, Skezza said:

Thank you. Tonight's sorted for me. 

 

Is it only larger hoses or smaller as well?

 

Will report back when I know more. 

 

There are only two and they're both large, often there is a rigid plastic pipe connected to the plenum and the turbo and shorter Flexis connecting them to the intercooler.

[Skezza]

20 hours ago, sepulchrave said:

 

There are only two pressurised boost pipes, one from the turbo to the intercooler and the other from the intercooler to the inlet plenum on the engine so you only have four joints to test, don't use your eyes, grab the pipe and pull it hard near each joint, any movement means a leaky joint.

 

I've checked them. Top one is moving a lot (I noticed this the other day). I've removed the pipe and re-seated with the circlip re-tightened on it, but it soon starts to slip. 

 

Is it a new pipe then? or new clip?

 

My yellow DPF light has come on 😞 Not sure if it's related or possibly due to the 200 mile drive where I only made about 1psi boost on average.

[sepulchrave]

Yes, get a new clip, order a Mikalor clip in the correct size.

 

It was the 200 mile drive wot done it.

 

Fix the leak, then you can worry about getting the DPF clean again.

[Skezza]

Hi, 

 

So it's this clip. I'm struggling to find one by Mikalor but I've seen Febi do them?

 

I noticed there are also O rings on the connector. Are they likely to be the culprit?

[Skezza]

In the first instance going replace the rings, see if it helps but I suspect the nubs are worn tbh. 

[sepulchrave]

It'll be worn but if the joint is not popping off you need to look elsewhere for the problem.

[Skezza]

7 minutes ago, sepulchrave said:

It'll be worn but if the joint is not popping off you need to look elsewhere for the problem.

The joint isn't popping but it's moving a lot. I've ordered the O rings. They'll be here today. I might try and wrap it with some duct tape and if the issue goes away (albeit temporarily) then we have our issue. 

 

It'll either be a new set of o rings or new pipe I think. Although I noticed people on the internet are using metal spacers that are bolted. I can't find anywhere selling any premade with a 54mm ID 😞 could potentially make my own though. 

[Skezza]

6 hours ago, sepulchrave said:

It'll be worn but if the joint is not popping off you need to look elsewhere for the problem.

Sadly, you're correct 😞

 

O-rings arrived.... replaced... made absolutely no difference. In fact, I've put the original O-Ring back on for the time being. It just looked a bit better quality although that's probably just because it's black and this new one is green...

 

So... back to the drawing board. I had a really good go (again) at all of the joints and none of them are visibly moving with the exception of the one at the top and none are popping off whatsoever. I also clamped the same top hose with a g-clamp to test and the issue still occurred, so I somewhat need to start again.

 

So far, I've checked the four pipes at the joints as best I can, and all appear to be pretty solidly attached. Is the next step to start removing the pipes and checking for cracks and splits? Checking to the intercooler is relatively straightforward, although removal might not be quite as easy.

 

The only other thing I've been able to find on the internet is the EGR cooler apparently can cause similar issues? I'm not entirely clear where that even is on my car, but I'm guessing (From an exploded diagram) that it's tucked behind the turbo making it a real pain to get to. 

 

I could buy a leak tester kit? If I blew pressurized smoke through the top hose as per one of these kits, I assume it would expose any issues in the system including after the intercooler?

Edited 30 May by Skezza

[Skezza]

I've now followed the entire system from one end to the other. The only place where it appears to get really really dirty is around the back right under the turbo. No idea what is around there but the hose seems a bit weepy.

 

I'm still not happy with the joint at the top. I checked my Jetta and the top intercooler joint is rock solid. 

 

Is there any way I can be sure / test this?

 

 

[sepulchrave]

With no evidence of a boost leak I'm starting to suspect the turbo itself...

[Skezza]

So I'm starting to think so as well, if I reach around the back of the turbo (not sure what's behind there), it's quite dirty. Very dirty. I shoved my phone back there.

 

 

I can't really tell, but is that the turbo? That pipe to the right surely is the inlet side of the turbo?

[Skezza]

 

Started trying to capture various bits of video and what not. You've got that which is very dirty as well.

[Skezza]

So I tried to test again. I've noticed it's quieter when you first start the engine....

[Skezza]

Booked it in the garage, for the 12th. if by then, i'm still stumped at least I've got a backup. 

 

I did a load of reading up last night. I'm not a mechanic btw or even a 'home expert', i can just about find my way around a car and definitely can if there's How To/Tutorial.... as such there's every chance the statement I'm about to make is completely wrong, but as I understand it, if the turbo was leaking oil past the seals, i'd have some blue or white smoke, which I don't. If I had a blown turbo, again smoke, which I don't. What I'm suspicious of in the above posts is the wet and dirty inlet port on the turbo and around it, but again, if my understanding is correct then a serious split in that region would more than likely result in smoke.

 

I have a code P0471 - https://www.obd-codes.com/p0471

 

Which leads me to two legit possibilities:

- Compressor wheel in the turbo is noisy.

- Intercooler Leak.

 

I haven't really been able to assess around the intercooler as it's pretty tucked away.

[Paws4Thot]

22 minutes ago, Skezza said:

if the turbo was leaking oil past the seals, i'd have some blue or white smoke

Almost certainly yes.

And if you had a boost leak on a TDi black smoke.

[sepulchrave]

http://wiki.ross-tech.com/wiki/index.php/16855/P0471/001137

 

If the leaking oil seal were on the cold side of the turbo then you'd have oily pipes, oily intercooler internals and a damaged impeller.

 

Remove the TIP and grab the impeller nut, excess endfloat or movement side to side means the impeller is damaged and you need a new CHRA cartridge or a complete turbo.

[Skezza]

2 hours ago, sepulchrave said:

http://wiki.ross-tech.com/wiki/index.php/16855/P0471/001137

 

If the leaking oil seal were on the cold side of the turbo then you'd have oily pipes, oily intercooler internals and a damaged impeller.

 

Remove the TIP and grab the impeller nut, excess endfloat or movement side to side means the impeller is damaged and you need a new CHRA cartridge or a complete turbo.

For the uninformed, i.e. me, the 'cold side' of the turbo I'm assuming is the air intake side, rather than the outlet? I think that makes sense. The pipework itself seemed dry enough, it was just that little section of the turbo, but having done some more and video recording behind their, I'm starting to think the oily pipe I found earlier may just be an oil return pipe and apparently it's normal to have a bit of oil hanging around there. Possibly another red herring.

 

TIP? Top intercooler pipe? Again, assuming based on the statement after   I'll go and give it a try though.

 

Turbo for this car doesn't look too expensive. £150 seems to get a refurbished one. It doesn't look a particularly challenging part to replace either, other than the access which is kind of awful. Still need to confirm it's definitely the issue though.

 

Going ask my partner to nudge the car forwards and backwards today while I observe the engine bay and see if I can find it from there.

[Skezza]

So I gave it a go and it wasn't possible for me to figure out the source of the hiss. I can't tell if it's the turbo itself or a leak in the system, but I think I'm going to admit defeat and book it in sooner. Quite curious what it turns out to be.

[Skezza]

So I dropped it in the garage this morning. They think it might be a blocked DPF but I'm really not sure by this diagnosis. The issue first started occurring off the back off the back of a really good drive. Well over 200 miles. I would have expected the DPF to be given a good working out during that trip. He seems to think it needs a 'flow' test or something and he thinks it might be pressure coming from the exhaust manifold?

 

I'm dead confused by this. I'm confused how it would cause the whoosh sound....?

 

Any thoughts? 

[sepulchrave]

Yes, it's nonsense.

[Skezza]

1 hour ago, sepulchrave said:

Yes, it's nonsense.

Got the car back. Had a bit more of a chat with them. I wasn't that impressed. Seemed they had loads of work on, which isn't their fault of course but it felt like they'd spent a very short amount of time diagnosing it and had jumped very quickly to conclusions. I can't tell that they've removed many hoses which means I'm curious how they compression tested the system.

 

They think it needs a DPF Terra-clean. They said the leak is coming from the exhaust manifold. £250 for the service. I've told them I'll have a think.

 

I think I'm going to take it to a second garage.

 

I spent an hour Googling before I went to pick it up. I'm no mechanic by profession and I'm no armchair mechanic either but the symptoms just aren't lining up here.

• Loss of power - Yes, somewhat, but the car wasn't exactly a beast to begin with and I drove it carefully after the noise started.
• Reduced fuel economy - Not noticeably.
• Excessive exhaust fumes - No.
• A hot and strong smell from the engine - Not as such.
• Poor acceleration - Again, maybe a little, but I'm not booting it either.
• Start/Stop may stop working - Not applicable.

I should be smelling diesel fumes as well apparently, which I don't. The car is kind of driving OK, but it's noisy and I'm not really driving it hard.

 

Whatever the issue, still for me, sits in the boost system. 

 

Is the turbo actuator something I can easily check?

 

I'm back to square one a bit. The second garage are taking it in on the 19th June.