cause of leaking cam cover gaskets??

[dhali]

i found this and its quite intresting. Could this really be the cause of so many leaking cam cover gaskets/tensioners?

http://forums.audiworld.com/a6/msgs/486032.phtml

[wozza]

Short answer from me, is a deffo yes, as I've just done a pile of work on my Rs4 and things are looking a lot better..

in that

- less oil in the inlet Y pipe..
- Found one vacuum leak in one way valve (which feeds brake servo)
- found small vacuum leak in booster/suction jet pump
- found the one way flap valve (connected to booster valve) to the oil breather circuit was faulty.

and FYI

- Found one vacuum leak in small vacuum hose feeding valves for secondary air and airbox flap, and feeds off the DV circuit - net effect was causing issues in overrun on gearchange causing EGTs to go nuts. (also other ancillaries weren't working)

Anyway some detail: Excuse the essay.

I spotted the article and have suffered from camshaft oil seal issues about 6 months ago, have also suffered oil from the vapour recirculation circuit getting into the Y-pipe on the inlet side and then getting into the intercoolers (about 10cc's in both).

I could'nt get a decent explanation for most of these issues - other than the turbos tend to harden the oil seals at the back of the engine over time (also the flexi hose to the air pump for emissions reduction).

Having got the booster valve/suction jet valve off and checked it to see if the valves were working there did seem to be a minor leak there (with the one way in the booster/suction valve and in the one way that also goes to the brake servo) so I blasted both out with carb cleaner which cleared the crap out and they then sealed ok.

Looking at the article and the diagrams in SSP198 pg 30, I don't see how this booster can cause issues with the oil and seals as it's a closed loop from and back to the inlet manifold - but what I did notice was that the smaller one way valve which links this lot into the oil vapour breather lines was also clogged with crap and I also blasted this out with carb cleaner as this wasn't sealing at all well.

What this one way valve does I believe is stop compressed air finding it's way into the rocker covers and inlet manifold when on boost, and on vacuum should draw out the vapours into the inlet manifold. But if faulty I figure will pressurise the engine cavity. Ok so theres the pressure limiting valve that should stop oil etc entering the Ypipe but if this closes and the other valve is duff you're going to blow an oil seal somewhere.

AlSo I figure that just before the pressure limiting valves close, and reopens youre going to get oil being blown into the Y-pipe.

FYI Also found the boost leak which feeds off the metal vacuum pipes and feeds the airbox flap and the Dump valves - which some aggressive mechanic nailed because they couldnt be bothered to take the metal clip off and instead forced it and split the pipe. The pipe comes off bottom of metal pipe from Divert air valve for turbocharger N249 - under fuel pressure reg and back a bit (ssp198 pg 28). And due to this the Dvs had little vaccum to operate so my exhaust gas temps were going bonkers after changing gear i.e engine run on - secondary air valves we're opening correctly on start, and I guess vacuum reservoir I doubt was being charged. Also b*ggered my fuel economy.

Anyway once sorted, reset all fault codes - which should clear the fuel trim and will relearn and re-calibrated throttle.

Fuel economy is now up as I've nailed the vacuum leak, DV's are working properly - and having cleaned out the valves and this circuit and driven 500 miles theres *significantly* less oil in the inlet manifold Y-pipe.. And my oils seals, I hope are safe. Well they're new so bl**dy should be!

Hope guff this helps.

[dhali]

now that seems a lot clearer

only joking mate, my gaskets have been replaced TWICE and the last time the tensioner seals were supposed to have been done too but still after a while i get a leak so i will be replacing those two items you mention. The one way valve you mention is it the green one by any chance? And what was the approx cost of those two items?, do they keep them in stock or do they have to be ordered?

TIA.

[wozza]

Sorry - picture says a thousand words so see attached!

In the pic on audi world yeah it's the green valve my car has a black one with an extension coming off it for the brake servo. All were leaking slightly but the one going to the crankcase breather had the main issue and will be why, I believe the oil seals are blowing out.

Along with the small hose pieces, all the valves total cost was about 60 quid. But carb cleaner is a cheaper alternative possibly.

ps: I also replaced there are other green non return valves on my car that were duff, but these were not related to this problem.

[wozza]

I think the valves are generally available the one to the crankcase breather hadnt been ordered before apparently. I think I got the lot in a week, not put em on yet as the cleaned ones are holding up..

[neckarsulm]

Nice info - thanks

[quattrokid1]

i was going to ask if changing the cam cover gaskets was a job a total novice could do.... err obviously not then, I aint wading into this lot!!

[tdiquattro]

Just to add (for the S4 readers) the duff valve you mention as the cause (63 0n diagram) is the one on the bottom of the F-hose on the S4.

[flashyg]

I can only second these findings.
Many of the valves are in the direct firing line of the boost and simply get knackered.
They are easy to replace and essential for these cars to carry on working properly.
Great helpful discussion.

[Virdee Autos]

I ordered all the bits that were stated on the other thread. The suction jet pump and green valve and all necessary clips

Didn't order that no. 63, which I think i'll do tomorrow. I should have all the other bits on Monday, although they will be at the dealers tomorrow, just they don't deliver!

Wondering if I should order all the other NRV's...

Edited to say I'll order another green valve, and no. 56

[wozza]

I'm sat looking at my new non return valve (56) (yes xmas TV is really that crap at mo) - there are 3 extra connection points coming off it - two small and one large. Methinks my garage ordered a later one or it's a new revision. May have to blank off extra connections with a spare bit of vacuum hose or take it back (let me know if you find the same)..

Suction jet/Booster valve (52) is the same as before so is the boost valve thingo (63)...

[Virdee Autos]

Ok mate will do.

My other bits should arrived on Monday, but none of these are no.56

I will be ordering no. 56/63 and another green valve on Monday, but I guess I won't see them before the 2nd for sure!

[dhali]

can anyone tell me what type of tool is required to get the oem type clamps back on? and where i may be able to buy it?

[boxerdogted]

You can't re-use these clips, if you intend to clean/replace at regular intervals use good quality stainless jubilee type clips.

[dhali]

sorry what i should have said is replace with new oem type clips.