2008 Multivan 2.5 tdi oil leak in air inlet before turbo

[Silver Caravelle]

Gday all,
Lately I have been investigating oil pooling and leaking through black plastic elbow join from air inlet to turbo of the Multivan (128kw tdi)

My mechanic has cleaned it up and is inquiring re new seals for this elbow to stop the oil leak onto the under tray to at least slow down the leak for now and monitor. We discussed whether the turbo is leaking oil into the elbow as the route cause.The engine runs great with no performance issues and I skeptical that the turbo is in need of replacement. Has done 149,000k.

I am now thinking it is excess oil coming out of the PVC into the air inlet tube ( that then joins to the black plastic elbow and pools oil there). I have pulled the PCV hose off and there is a reasonable amount of oil residue, more than just blowby mist.

There is also only oil mist in the intercooler pipe side of the turbo which is a great sign of no oil spewing from the turbo outlet.

If the PCV is knackered letting excess oil to blowby from the rock cover, is there way to test this without accessing the rocker cover? I cannot see that it is straight forward to access this and replace the PCV without major surgery to remove the plastic rocker cover and intake manifold.

Thoughts would be greatly appreciated.

Regards,

Scott

[Greg Roles]

PCV for sure. My turbo is at 267kms and still pretty oil free. Unlikely to leak BACK out the intake, it blows any bearing leak blowby into the intercooler. You'd be wise to fit a Provent 200 catch can in between rocker cover and intake inlet, here's a pic of mine, with a drain hose down to the bottom of the engine with a small plastic irrigation tap at the end for periodic draining. The cheap Provents on eBay are China ones with a basic mesh grid, nowhere near as good as the real deal at about $180, but better than nothing. I run the real thing, and have a China first stage with real Provent second stage on my Yeti, seems to work well.

Ribbed hoses from HKBPerformance on eBay out of SA.

[gregned]

Hi Greg
Thanks for the pics, how and where is the provent attached to the van?

Any pics of the bracelets or how it’s attached?

Cheers

Greg

[Silver Caravelle]

Hi Greg,

Thanks for this and noted re Turbo. I have been checking out whether to go the Provent path as alternative fix. The absolute level of tear down it seems to replace a PCV inside the rocker cover, forces one down the Provent path. The only thing though now, is potentially topping up with oil periodically, given oil still escapes from rocket cover to Provent. Otherwise engine has not needed top ups between each service.

Regards,

Scott

[Greg Roles]

Hi Greg
Thanks for the pics, how and where is the provent attached to the van?

Any pics of the bracelets or how it’s attached?

Cheers

Greg

Zipties to nearby things using the supplied Provent can holder. I'll make it better down the line.

[Greg Roles]

Hi Greg,

Thanks for this and noted re Turbo. I have been checking out whether to go the Provent path as alternative fix. The absolute level of tear down it seems to replace a PCV inside the rocker cover, forces one down the Provent path. The only thing though now, is potentially topping up with oil periodically, given oil still escapes from rocket cover to Provent. Otherwise engine has not needed top ups between each service.

Regards,

Scott

Mate I've never had to top up between changes with a Provent, it's still normal loss, the rocker cover system is hindered by the heat and short route it takes, hence why my Provent is over the other side giving the oil as much time and distance to cool as possible.

[Silver Caravelle]

Cheers Greg. If say the PCV is working correctly as designed, does this ordinarily minimize oil loss from the rocker cover with only prodiminately oily mist blow by? Where as when the PCV is faulty, more oil leaves the rocker cover into the Provent whether the hoses are long or short? Unless there is a good way of recirculating the oil?

Thanks,

Scott

[Greg Roles]

Yes, but the rocker cover PCV is a static "maze", it can't really "wear out" or stop functioning. In your case to stop the pooling it's catch can time. Rocker cover PCV systems work as intended, you add a catch can to stop the overflow the rocker cover still lets through, there is oil blowby "mist" from brand new, it just takes time to coat the intake and start pooling. Your EGR valve area where the engine also adds soot is where the real fun begins. Oil blowby plus soot equals 3D gunk buildup all the way to the cylinders. Problem of modern direct injection cars that don't have a carbie and wash the intake out.

[Silver Caravelle]

Many thanks for the info Greg.
Cheers,
Scott

[Silver Caravelle]

Hi all,

Please see the link below re PCV(s) for the R5 2.5 engine. Attribution to Gnits; Club Tourareg Forum.

It turns out the PCV(s) set up is a little more convoluted and is integrated into the rocker cover with two separate items. On the 2008 T5, it is even more complicated to remove the rocker cover to inspect for perforation of the PVC(s) membranes. If some of these individual membrane parts are not entirely available, then it looks like a complete new plastic rocker cover. What a nightmare.

If these PCVs are working correctly, the oil flow to air inlet duct from blow by should be minimal with predominantly oil mist. If there is a perforation, then oil flow with blow by is likely going increase.

I can see why a Provent is a solution to catch excess oil, but the route cause is still sitting under the rocker cover!

DIY: Touareg 2.5 TDI R5 valve cover PCV valve repair / diaphragm replacement | Club Touareg Forum
DIY: Touareg 2.5 TDI R5 valve cover PCV valve repair / diaphragm replacement | Club Touareg Forum

Cheers,

Scott