Mk5 Golf TDI EGR Valve Fault.

[jets]

I have posted before on this forum how reliable my Golf has been since new. It is now virtually 9 years without a single fault.[2006 model manufactured in late '05]. However the perfect record has been broken with the sound of a gong & the words something about emissions, Workshop. A check with VCDS showed 16785 EGR System & P0401-00-Insufficient Flow.
There was oil coming from the vent hole on the EGR as well as at the joins in the boost tube. Transporter had mentioned in an early thread that every Mk5 Golf he had looked at, including their own had oil appearing from the same places.
Here is mine after removal.



I was expecting the throat to be very blocked as others have posted but mine had only a small amount of carbon covered in oil. I believe that is a result of my driving style. I don't boot it at low revs.



I wasn't able to check the diaphragm for leaks because I don't have a vacuum pump. Before I could look to see if the spindle was clean where it enters the body my friend who was with me pushed on the valve[where the exhaust gas enters] with a screwdriver & the valve opened.
On an Audi forum site, a well respected poster said in relation to someone else's question with the same code, if it's the 2.0l engine don't bother trying to clean it because the codes will just reappear.
The valve was a WAHLER brand [I hadn't heard that name before either] Pt No 038 129 637D.
I found one on Ebay from Poland for $120 including P&P & exchange rate cost, posted to my Post Office.
It took longer than I had expected, almost 3 weeks but finally arrived. It is made in Germany with the same brand as the original.
I had the usual difficulty undoing the long screw on the LHS & found a 1/4 ratchet with the 5mm hex insert entered from under, & on the RHS was the thing that worked for me. If you can fit a torque wrench, the 5 screws are 10Nm & the 2 larger screws through the flange on the exhaust gas pipe are 20Nm.
I also had the boost pipe blow off on my first drive but by pulling up without releasing the clip I heard/felt it click in position & has been good since. I also had to clear the previous stored codes after the new valve was fitted.
This pictures is of the sleeve that VW has fitted over a coolant hose that I believe is to protect the rubber from the oil that will leak from EGR. Not an if but a when.

[Umai Naa!!]

Surprised you've gone this far before needing to replace it. It's a pretty common fault.

I'd say that rubber sleeve is more to do with preventing chafing of the coolant hose on nearby components than anything else.

[asa572]

I'd say yours isn't carboned up because it hasn't been working properly for a while.
I cleaned my egr and flap valve at around 100,000 k's and it was leaking out the diaphragm holes.
Both the egr and flap valve were gummed up pretty bad.
The egr ended up throwing a code at 150,000 k's and when I removed it, it was pretty much spotless like yours.

[jets]

I'd say yours isn't carboned up because it hasn't been working properly for a while.

Maybe the valve hasn't been opening fully but just enough not to throw a code. Owners say if you blank the pipe off completely a fault will show immediately. Forgot to say my Golf has only travelled 72,000km. I am retired & have three cars registered.

[jets]

I'd say that rubber sleeve is more to do with preventing chafing of the coolant hose on nearby components than anything else.

You could be right but I know diesel rots coolant hoses & I have seen tyres on agricultural equipment rot with transmission oil. I can't say what engine oil does & whether the coolant hoses are still made from rubber or some other compound. On the VW they certainly last a lot longer than in the good old days.

[Ryeman]

........
On the VW they certainly last a lot longer than in the good old days.

I'll hold you to that ))

[Transporter]

The cooling system hoses are generally not resistant to oils.
I've seen some aftermarket hoses start perishing within 12 months after replacement. The VAG hoses are much better quality.