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Old 20th April 2022, 08:26 AM
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Default Cylinder head end cap. Old vs New design

So the V6 and V8 engines have these cylinder head end caps for the cam shafts.

The current design is just a piece of pressed aluminum coated in rubber which gets pushed into the hole. I've had these replaced on my car a year ago and they are leaking straight onto the exahust, so If I'm going to replace them I will probably coat them in sealant too..

The old design for these used in Audi 100 era V6 engines was a machined piece of metal with an o-ring going around it, these are hard to find but still available..

My question is:
Am I better off using the metal cap with an o-ring or the current single piece cap? looking at both designs the one piece rubber coated cap would have a lot more sealing surface (especially coated in sealant) than the o-ring.. but also is a lot more suspectable to temperature and pressure being so thin..
I think VAG just changed and worsened the design cost cutting purposes.

pic for reference:

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Old 20th April 2022, 08:57 AM
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Quote:
Originally Posted by Ronin View Post
...so If I'm going to replace them I will probably coat them in sealant too.
This. It appears from the instructions in ETKA, the end caps are supposed to glued in place. This applies to both of the versions you showed.

D176501A1 is described as 'Silicon sealant' and costs 25. As they say, other brands are available.
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Old 20th April 2022, 12:34 PM
MikkiJayne MikkiJayne is online now
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Good find ^ I've never noticed that. Big Red's went in dry and aren't leaking so I guess I got lucky on those. I wonder what is different on the V6 to the V8 that requires sealant?

Elring Dirko is the aftermarket version of the OE sealant
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Old 20th April 2022, 12:44 PM
ainarssems ainarssems is offline
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There is more than one Dirko isn't it?

I think there is at least grey and red with the red being for higher temps
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Old 20th April 2022, 01:00 PM
MikkiJayne MikkiJayne is online now
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The grey one then
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Old 20th April 2022, 02:02 PM
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Quote:
Originally Posted by MikkiJayne View Post
Good find ^ I've never noticed that. Big Red's went in dry and aren't leaking so I guess I got lucky on those. I wonder what is different on the V6 to the V8 that requires sealant?

Elring Dirko is the aftermarket version of the OE sealant
Higher oil pressure being a smaller engine? i can only guess.

I think i'll order a pair of metal caps and see how it goes.
The part number for the o-ring is no longer on etka so i will have to experiment and find one that fits
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Old 22nd April 2022, 10:22 AM
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I found an older version of the parts catalog where description doesn't say to use the new cap as the solid metal one is obsolete but instead it says "for engines without vacuum pump", I wonder why that is... I guess the pressure in the crank case is positive so it needs better seals?

078145117E
O-Ring f. engines without vacuum pump

078103491A
bungs f. engines without vacuum pump
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Last edited by Ronin; 22nd April 2022 at 10:50 AM.
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