Oil in multiple cylinders - constant misfires, no power etc..

A6 All/ S6 All
#1

Hey guys,

I was able to clear up my initial rough idle by fixing a vac leak post throttle body as it mated up to the intake plenum. Was also able to clear up misfires by changing all coils and placing in new plugs. Had a full carbon cleaning done as well. After all this work the car was CEL free for about two months.

Suddenly one morning after the car warmed up I was on the road and noticed a lack of power, shuddering misfires when on the slightest bit of throttle and the CEL came back on. I have little to no power with moderate throttle. CEL flashes.

I pulled and inspected the coils and plugs. cyl 2-4 and 7-8 plugs covered in oil… enough to coat the socket when extracting the plug. Coil packs covered as well, though I don’t believe fully up to the electrode.

I’m assuming this is the cause of my misfires and lack of power/rough acceleration.

I’ve hunted around for valve cover gasket sets and since my S6 has a 3/22/2007 build date, they no longer manufacture full gasket kits for both banks. I would need to buy a full valve cover with installed outside gasket and separately purchase the inside. Oddly enough the left bank is available as the standard set without valve cover.

Dealer wants $530 - ECS/others are back ordered without any delivery date.

Before consider this expense, is there any way to inspect and determine if the leak is in fact from the VC gasket around each plug cyl or could it be from the lower gasket where the head mates to the block?

Can anyone provide insight?

Has anyone had to replace their VC gaskets?

Hoping to make a decision quickly to fix this weekend if I can have parts in time.

#2

I recently did a carbon cleaning and intake manifold spacers on mine and found oil in a few of the spark plug galleys. Thankfully, i’m not having any misfires or CEL’s, but it’s difficult to tell if it’s from the VC gasket or the lower seal between the cam caps and head.

For me, I didn’t do the Valve cover gaskets as it looked like the oil was starting to seep down from the seal below it. For those i’ll wait until I pull the motor and do a full re-seal on it.

As for determining which seal is leaking, try removing one of the easier to access coil packs (that has an oil leak). Then clean up the oil with some cleaner and a shop vac with a straw/small hose attachment to get everything out of the galley. Then put everything back together and drive for a few hundred miles and pull the coil pack back off (carefully as not to spread any of the oil around). Hopefully then you’ll be able to see the residue and determine exactly which seal it’s leaking from.

#3

JRach great advice.

Rally if you see oil in the cylinders it’s probably not n the Valve cover gaskets. The spark plugs block the cylinders form getting oil in them.

There are three spots you can get oil into the cylinders from the top of the motor.

Area one from the spark plus hole but you would need to remove the spark plug for oil to get past it. You could poor a gallon of oil on top of the spark plug in its hole and none of it would get into the cylinders

area two from the injectors. But again the injectors much like the plugs are air tight sealed. So no oil is going to get part there. Lastly THE Intake Ports FROM THE Intake Manifold. Your pcv system can be faulty and that would cause all kinds of oil to get into the cylinders. I would check there first

#4

Thanks, guys.

JRach - I should clarify, I’m not seeing oil specifically in the cyl after the plug. I’m seeing resting oil around the plug in the galley. When pulled a couple weeks ago oil was also covering the threads heavily and dripping.

I just pulled cyl 3 that recently had oil issues. Not nearly as bad but there was some new oil resting around the plug at the bottom. I made sure to clean and wipe the galley down last time I was in there and looking now it seems the VC gasket may be weeping oil. You can see two distinct seams 1st where the VC gasket is and 2nd where the lower seals are.

PCV oil separator was replaced when I bought the car at a local dealer. When I picked up the car it was squealing badly from the rear main seal.It does still sounds and feel like there is too much suction in the system. You can hear the suction and a big stumble in the below clip I just recorded. What you can’t hear in the video is what sounds like suction building back up slowly after the cap is back on. Ignore the dirty engine… Vermont mud season! Same thing happens when you remove the inlet hose on the separator from the right bank. It does appear to have a good amount of sludgy oil on the inlet lip.

https://www.youtube.com/watch?v=S0fnu7RIE4M

I was going to remove the separator and try to pop the back off where the diaphragm is located for inspection, but didn’t want to risk breaking the casing. Anyone have a write up for this? Also has the OE crimped clip on the bottom drain line and don’t have a smaller clamp to replace it with.

It is odd that I had these exact same symptoms before changing all of the plugs and coil packs… then the symtoms slowly returned. Would either a leaky VC gasket seal in the galley or access crank case pressure (perhaps pushing oil past the gasket) foul new plugs that quickly?

I could purchase all new plugs or have a friends shop blast my current set clean (did this with my oil happy B6 S4) to see if at least in the interim the misfires go away… if so, then I’d look at replacing the separator (which is still under Audi warranty) then the VC gasket if the problem persists.

Sorry for the winded reply! The help is greatly appreciated. I just want this car to be enjoyable for longer than a month at a time!

#5

Dang, I wish I kept my old/faulty oil separator. I didn’t know that you might be able to replace just the membrane. I shelled out for a new one.

http://audirevolution.net/forum/index.php?topic=3753.msg109003#msg109003

Also, the spark plug gaskets you refer to are these:

1 x (OEM-07L103650A) - Seal, Gasket for Spark Plug Bore, Cyl 1-5, Right (OEM) for C6-S6 5.2L FSI V10
1 x (OEM-07L103649A) - Seal, Gasket for Spark Plug Bore, Cyl 6-10, Left (OEM) for C6-S6 5.2L FSI V10

I was getting the same problem with oil down in the coil packs. The gaskets were dry and brittle when I replaced them.