Guidance on oil leak in Audi A4 B8 2.0l CAGA TDI engine (with photos)

[SchrodingersCat]

Hi Folks,
I was wondering if anyone had any experience with the following.
I was changing the oil on my 2008 Audi A4 B8 TDI CAGA 2.0l saloon when I notices that there appeared to be oil on the sump in two places.
One was localised to the drain bolt so I wasnt worried about that, I can just make sure to tighten the bolt.
However, there appeared to be a larger blotch on the side wall on the opposite side. It went from the underside up as far as the bolts for the sump pan. It could have gone further but I coulrnt really tell.
I gave the underside engine bay cover a look but there didnt seem to be too much oil on it, so the flow must be small for now.

However, in case it escalates, would anyone have a suggestion of what could be causing the issue and how to go about fixing it?

In the time being, I was going to powerwash the underside and leave it for a day or two to see if I can see more easily where the leak is coming from.

Thanks!


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[Crasher]

Looking at the colour and wetness of the oil I would suspect that is crankcase ventilation and turbo compressor side oil vapour which has that characteristic look to it, this vapour condenses in low points of the charge air system then the liquid slowly creeps up and then weeps from the fast fit couplings to the various components such as the inlet manifold flap which is straight above the leak, put your hand under the coupling from the rubber hose to the flap and see if it comes out wet and black.

[SchrodingersCat]

Hi Crasher,
Thanks for the response. What you are saying could make sense: the under engine tray did not have much sign of oil on it. This means that the oil "leak" could be oil vapor that is condensation on surfaces nearby of the engine. The oil did look very thick, black and "dry". I will do a bit of research and see if I can find the area that you are taking of to put my hand in to check if there is oil.

Do you know where the typical areas are for this oil vapour to leak from so that I can see if I can repair it?

[Crasher]

It can weep from all of the charge air system coupling points even though yours has the improved type (actually more like the old way of doing things) and with the CAGA the throttle valve unit and EGR valve going into the manifold weep at their junctions BUT you will have the early inlet manifold and these are prone to problems and leaking air which lets the oil out.

[SchrodingersCat]

Sure enough, on your information, I had a look around the engine and found that the highest point that the oil had covered appears to be at the junction of the EGR valve.
This fella seems to have the same problem withe the same engine here: https://www.audi-sport.net/xf/thread...e-pics.209564/

Thanks for your help with this!
I took off the black hose (see photo) which allowed me to get a 1/4 turn on some of the torx bolts holding the valve. That should hopefully slow down the leak while I research what gasket to get.

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[Crasher]

I would expect the inside of the EGR motor cover to be full of oil and it is also leaking from the inlet manifold motor flap cover, if with us I would be recommending a new manifold, EGR valve and throttle valve as the insides will be ditched and you may have clogged inlet ports as well which is a grotty horrid nasty job to clean out. It is all typical EA189 problems.

[SchrodingersCat]

Thanks again for the response.

Ugh........if what you say is true and I have to buy a brand new EGR valve, throttle body and inlet manifold, it will be expensive :-/

I went ahead and removed the throttle body and the EGR. Both were very straightforward to remove, I followed the video here for the throttle body Démontage papillon d'admission d'air 2.0 TDI 143 CAGA (intake manifold flap removing) - YouTube and the video here for the EGR valve Démontage vanne EGR VAG AUDI A4 B8 2.0 TDI 143 CAGA (EGR removing) - YouTube. They are in french but if you turn on Closed Captions (CC) and auto translate under settings, you will get the jist of it. There is also a video for removing the Inlet manifold here: Démontage collecteur admission VAG AUDI 2.0 TDI 143 CAGA (Intake manifold removing) - YouTube. I didnt remove this part (yet) as it was a good deal more complicated.

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Both the EGR (03l 131 501 D) and throttle body (03l 128 063 B) were caked in about 2-3mm of soot.
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I cleaned both out in petrol, cloth and screwdriver.
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I opened the electronics box of the EGR valve. It looked fine inside, dry with just a bit of motor dust.
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Then I opened the throttle body electronics box. Unfortunately it was full of oil, just like you predicted.
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I cleaned out the oil and put it back together. I cleaned out the hole into the Inlet Manifold as much as I could with it still in place.

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I put everything back together. I brought it for a drive, and the car ran perfectly. I checked VCDS afterwards and there were no errors.

I opened the bonnet again and had a look at the three components again. Unfortunately, I could see some oil weeping from a hole on the side of the EGR valve, as indicated here:


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So although the EGR module and throttle valve module needed a good clean, the original problem of the oil leak is still there.

Am i right in saying that the leak through the hole in the EGR module is caused by a worn bushing on the piston and cannot be repaired? And that its a similar story for the oil getting into the electronics of the Throttle module?

I have the metal intake manifold, although I have seen more black plastic ones for the B8 2.0 TDI for sale. Is this the improved version?
If so, I will head to the Audi dealership and see how much a new throttle valve, EGR, Intake manifold and relevant gaskets and seals will cost me. If it is too expensive i will look at some second hand ebay parts.


Thanks again for your help!

[Crasher]

Could you message me your VIN?

[Crasher]

Your car was built 10/03/08 and has the early problematic manifold 03L 129 711 E used upto 17/08/09 and these are £472.88 new from VAG. The EGR valve is 03L 131 501 K at £271.54 and the throttle valve is 03L 128 063 AF and costs £265.69 but the latter two are available aftermarket. I don’t know of any cost effective way of getting around this as I have to look at it from the perspective of charging labour and offering a warranty.

[SchrodingersCat]

Thanks for looking up the part numbers Crasher.
So the list of parts that I will need to get are:

1. Intake Manifold: 03L 129 711 E ( £472.88)
2. EGR valve: 03l 131 501 D (model on car), 03L 131 501 K (latest model, £271.54 )
3. Throttle valve/ Intake manifold valve 03l 128 063 B (model on car), 03L 128 063 AF (latest model, £265.69)

I understand what you are saying with regards your perspective to labor and warranty, but i will have a look and see what I can find in good nick on the second hand market myself.
One other thing, is it possible for me to get the newer, improved black plastic intake manifold 03L 129 711 AG with the previous metal manifold you gave the details of?

Cheers for the help.