Changed PCV & N80 valve

[ven0m]

Hey guys, to follow up on this thread http://www.audizine.com/forum/showthread.php/691104-PCV-install-with-intake-manifold-in-place/page1

Symptoms:
- car was leaving a cloud of smoke when accelerating
- using up more oil than usual (within normal RS4 spec)
- when removed the oil filler cap, there is a strong vacuum and the engine started sputtering badly

My conclusion was that the PCV is on its way out:
- changed the PCV (got it for 140€ from the dealer)
- no more smoke and oil levels normal (better than normal RS4 spec)
- vacuum at oil filler cap persists (not as strong), engine still sputters (not as strong)

After this I read that the suction may be due to a bad N80 valve. So I got an N80 valve (20€ at the dealer) and changed it. Vacuum and light sputter still persist when oil filler cap is removed.

Is the slight vacuum and sputter still normal after changing both PCV and N80 valve? Car runs normal and strong, cylinder compression ok, etc. I also did a borescope and compression test, all cylinders are 11-12bar (160-175psi) and walls are like a mirror thankfully. Small noticeable carbon deposits on valves and pistons. Last carbon clean is 15k km (10k miles) ago.


New PCV:





Old N80 still installed during the PCV exchange:




New N80:










Compression examples:






Borsecope Bank2 Cyl5 examples:

Top piston & cylinder wall:



90° mirror borescope for cylinder wall and valves:




Borsecope Bank1 Cyl2 examples:

Top piston & cylinder wall:



90° mirror borescope for cylinder wall and valves:



Cylinder wall reflection:

[Quattrors4]

some vaccum is normal in the crankcase it should be -2hg to -3hg,when you open your oil filler cap you introduce a vaccum leak in the system and your short term ft will compensate,yes its normal if the engine feels rought

[ven0m]

some vaccum is normal in the crankcase it should be -2hg to -3hg,when you open your oil filler cap you introduce a vaccum leak in the system and your short term ft will compensate,yes its normal if the engine feels rought

Thank you for the quick and detailed explanation! I was thinking the same, reading the PCV threads in the A4 sub-forums.

[Quattrors4]

Thank you for the quick and detailed explanation! I was thinking the same, reading the PCV threads in the A4 sub-forums.

[IMG][/IMG]

[Fourplay]

As an aside, the PCV part for Q7s and Touaregs (with the lower revving 4.2FSI) is the exact same and costs fractions of the RS4 part cost.

Part number is: 079103464D

The only difference is that the oil drain tube at the bottom of the PCV points straight down instead of at a 90 degree angle, but it all still fits just fine.

[d2a4]

As an aside, the PCV part for Q7s and Touaregs (with the lower revving 4.2FSI) is the exact same and costs fractions of the RS4 part cost.

Part number is: 079103464D

The only difference is that the oil drain tube at the bottom of the PCV points straight down instead of at a 90 degree angle, but it all still fits just fine.

Great info. ECS has that part number for $260 but Amazon only $39. Why so much differences?

[Fourplay]

Great info. ECS has that part number for $260 but Amazon only $39. Why so much differences?

The ECS part is OEM, so it was made in China, shipped to Germany, then shipped to the states, then given the OEM VAG markup.

The Amazon part skips all of the intermediate steps. You're buying direct from the manufacturer in China. It is the exact same part, down to the cyclonic oil separators and rubber diaphragm.

[Lugi20]

Can we get some links to parts here gentlemen?

[your daddy]

has your coolant been dropping at all?

[d2a4]

Can we get some links to parts here gentlemen?

Just copy & paste the part number Fourplay provided in google search & everything come up nicely.

[ven0m]

has your coolant been dropping at all?

Nope, coolant was always at the same level. Only fluids topped up were oil and a bit of the hydraulic fluid, because I washed out the power steering pump some time ago.

[docurley]

Here you go

https://www.aliexpress.com/store/pro...557792601.html

[Fourplay]

Can we get some links to parts here gentlemen?

079103464D - oil separator for 4.2 and 5.2 FSI - $40

Amazon Prime link: https://www.amazon.com/gp/aw/d/B01GC...rds=079103464D

079103464F - RS4 specific part, identical to above part minus oil drain hose orientation (horizontal vs vertical) - $355

https://www.ecstuning.com/b-genuine-...cv/079103464f/

[2QK4U]

Question: Is there a timeframe/mileage when you should replace the N80?

[Dirtracer603]

I have recently been reading/considering going to atmosphere with my PCV gases with a drainable catch can and vacuum pump and also making necessary adjustments to the PCV port on the intake. Mainly to keep the intake clean from carbon deposits. Any insight from you guys on this?

Sent from my SM-G900P using Audizine mobile app

[Quattrors4]

I have recently been reading/considering going to atmosphere with my PCV gases with a drainable catch can and vacuum pump and also making necessary adjustments to the PCV port on the intake. Mainly to keep the intake clean from carbon deposits. Any insight from you guys on this?

Sent from my SM-G900P using Audizine mobile app

there is a good way to keep your intake manifold clean off oil I will post a picture of the set up a bit later ,the way people install there catch can is wrong on those motors that's why they don't work

[Quattrors4]

[IMG][/IMG]
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[Quattrors4]

[IMG][/IMG]



whats happening with the stock system is that there is so much oil going thrue the breather that it can t cope with all the oil in the ventury system and it cant drain it fast enough and some oil find its way into the intake manifold,by doing the set up shown above the catch can picks up all that extra oil and the intake manifold stays oil free

[CrickiKaze]

Yeah, you are aware that there is some what of a difference between how you set up a catch on a NA car versus an FI car right.....?

I still need to dig around on this motor but if the system is like normal, then technically we would need two cans or a 2 in/1 out can for pcv and vc.

[Quattrors4]

Yeah, you are aware that there is some what of a difference between how you set up a catch on a NA car versus an FI car right.....?

I still need to dig around on this motor but if the system is like normal, then technically we would need two cans or a 2 in/1 out can for pcv and vc.

I had the same system when I was na and it was just perfect,no trace of oil in the manifold,for the fi I use one more catch can with a 1 inch check valve to realease pressure on boost
for na you don't need 2 cans