2007 S6 intake work. Warped part and advise needed.

A6 All/ S6 All
#1

Hey guys! I’m new here. I’ve been looking for years. This place has been super helpful for me with my S6 for troubleshooting. I have a 2007 S6. So I just hit 100k miles on it. For the past couple of months, it’s been leaking oil all over the place and it was misfiring on 8 of the 10 cylinders. It’s bad. And it has an exhaust leak I believe is coming from the flex pipe, the first ones closer to the engine. So I pulled the intake manifold off a couple of days ago. Of course, it wasn’t the easiest in the world. But it’s off. Thankfully, no plastic bits came tumbling out of the manifold! I shook it and no rattle! So happy that none of those flaps are falling apart. So the motor is leaking like crazy on the driver’s side and the rear and front of the motor. I figure the oil filter housing is one of the culprits so I have that figure 8 gasket coming in. I also saw that the oil separator was covered in oil and the hose on the bottom of it was oozing fresh looking oil. So I have a new separator. Now on to the valve cover gasket for the driver’s side. Two of the bolts holding it down were super loose. Do you guys think that this is was caused the leak. Will tightening it help? I’ve read up on these and since I have an 07, I believe I have the old style valve covers. I can either buy a new cover with new gasket or modify a new gasket to fit my old cover. I see the difference in them and it’s minor. The new style just has gasket go around all of the #10 cylinder spark plugs and hole where old style went around about 75% of the hole. But, aside from that, there was like 2 inches of oil in all the spark plugs and holes on that side. I sucked it all out. But the souce of the oil doesn’t seem to be coming from the valve cover gasket. It seems to be coming from lower down in there. There is another joint in there and it seems to be coming from that. What joint is that? And is that a hard gasket to replace? I would assume it is probably super hard because it looks to be lower than the cams. I reason I might would have to pull the cams out to get to this level and replace that gasket down there. Am I correct? If that’s the case, I’ll just be leaking oil down in there for a while. Sounds like an engine out procedure.

Anyway, my checklist includes

  1. Clean intake valves/ports
  2. Replace oil separator
  3. Replace oil filter housing gasket
  4. Replace coil packs
  5. Replace spark plugs
  6. Replace valve cover gasket/driver’s side

Is there anything else I should be looking at or maybe replacing while I have this intake out? I want to make sure I get all this done while I have things semi easy to access. Any help would be appreciated!

BTW, the throttle bodies. When I pulled that top part of the throttle body/upper ait intake part off, I noticed that the mating surfaces on both sides of that intake where the throttle bodies go were warped to hell. Massive source of the running lean code I was getting. Anyone ever dealt with this warped throttle body mating surface? To be clear, it’s not the throttle bodies, it’s where they mount to on that upper intake manifold piece. I ended up using a flat file and filing everything down. Took me a long while because I had to make sure I had everything flat. Or flat enough. But what I ended up with is 1000% better than it was. I can guarantee there will be no air leaks there anymore. But just curious what could have caused the warping.

#2

well hello and glad to have you…

You have a log list there so I’ll work my way up it from the bottom.

The warped throttle body Y. These do warp and cause fuel trim code issues as you saw. One of the major issues from this… heat… I would strongly suggest you get a set of JHM intake spacers. Not only will it help with that but the long long growing list of issues that pops up when adding up all of the little issues that can go bad from just how much heat the S6 puts off. Also when you put back on the throttle bodys make sure to use a small beed of silicone it will really help.

aside from a good carbon clean and intake spacers if your replacing your oil separator you should check and test your oil separator return line. Just to make sure there are no cracks or back ups in the line.

The oil in the spark plug holes that’s a cylinder heat top gurdle gasket and its a bitch to replce and its a motor out issue. I would place and let dry some silicone in the plug holes around where the top gurdle meets the bottom and connects in the plug holes.

The valve cover gaskets. The gasket bolts being loose are most likely a result of the bad or failing oil separator and PCV system. When those go bad pressure builds up in the motor and crank case pushing out on the valve covers and everyother possible point. Add in the extreme heat and heat cycles that’s how the bolts can come loose. It might not be a bad idea to just replace the gasket. The cylinder head face and lower part of the head is also a good place to install silicone when putting in the new gaskets.

As for the need for the new valve cover. With all of the other work you have I would just modify your gasket.

The majority of the oil leaks stem from the PCV system not working properly. So don’t just replace the oil separator make sure to check all of the lines.

100k seems to be just the first place these cars need major maintenance from past owners.

Here are my other lists of you should look into

1 with the intake manifold. either take apart the intake it self or get an inspection camera in there to make sure the flaps work and are not just sitting in one spot.

2 if you haven’t already check the fuel filter. The FPR is located in the fuel filter. over time it can not only become dirty but weak

3 a big big must. Injectors are the number 1 sorce of misfires and its not if the injectors will go bad or need service its WHEN… Its a must… I would look into the JHM injector service. They are the only ones that clean flow and service these injectors at a high pressure rate. The JHM serviced injectors are better in some cases than new as they are all flowed. You would be surprised on just how far off flow wise some new injectors are.

I think that’s a big enough start list that is a really good place to be

#3

I had my throttle bodie “Y” manifold damaged somehow someone had put undue stress on im guessing the TB, so mine is actually cracked. I too filed and sanded it straight/flush. I found a second hand one out of Poland (supercheap compared to the rest of the world) so will change it out next time its coming off. NOTE The bolts that secure the "Y: manifold are alloy and snap easily if they have been on and off a heap. They are cheap (less than $1 each genuine)so suggest replacing them.

I agree with Justin (with pretty eveything always) IM spacers are worth the money - there is a review on them posted by me on this site.

#4

the flex joints IMO are engine out as well if you want them TIG welded with stainless rod. Only found one company that makes the proper 1.5"x4" full stainless flex joint for that.

Do able with a sharp bend MIG gun, but then it will rust. Ditto on the oil in plug well. My gasket was hard as a rock and crumbled when i took the upper cam carrier off. Again, all do to heat.

#5

Wow! Thanks for all the replies! Great advice! Hey Justin, I ended up getting a used valve cover gasket off of eBay for $125 that takes the new style gasket. I figured I get the right gasket and valve cover so I don’t need to do all of this all over. Modifying the gasket could have worked, but also there was that chance that it wouldn’t. I decided I’d rather have the updated cover and be done with it. I don’t think $125 was bad for a used one.
I’ll def be putting the silicone on my finger and running it down into the plug holes to seal up that girdle leak.
Where is the fuel filter at? I read somewhere by the front driver’s wheel? And the JHM injector service, I just send these off and they can service them? Are the injectors a pain to get out? I have everything out right now so it’s all open space, but that tube looks solid as hell and all. Looks like if I unbolt it, it’s not gonna budge. But let me know! If it’s easy to pull, those are coming out too.

Hey Neil, I’m half Polish! Yea Poland has a lot of dirt cheap stuff. I might ask my mom or father in law to try to source me a Y body piece from over there too since they live there(Gdansk).

As for the exhaust leak, I planned on pulling it out and then having it welded up. I think it’s the same section that would need to be removed if I went cat back exhaust or something. If I went and got the Miltek exhaust, that flex pipe section would be coming out to make way for the Miltek. It’s the flex pipe that is near the flange that gets to the cats. I didn’t think it was an engine out thing. But I may be wrong. I hope it isn’t engine out. I just wanna pull the whole exhaust section out and weld it up. I might sandblast it after the weld and gunkote it or something to keep corrosion away in the future. Gunkote is pretty good stuff.

#6

I forgot to ask in my last reply, I read somewhere else that the new valve covers for the driver’s side had metal plate? Is that true? The used cover I bought didn’t have a metal plate. But I know it takes the updated gasket because I saw the pics. It’s different from what I currently have. So I know this used cover will accept the newest style gasket. But just confused about this metal plate. I read it was to prevent warping? Any truth to that? I tried to Google some pics up but couldn’t find anything showing theuodated covers or any metal plates for that matter.

#7

Uh nope. I am wrong Greg. The cat backs mount right at the front pipe. Then it splits up to the cats and heads. This sucks. I am not pulling this motor out for that. I am wracking my brain on this. I have an idea. Let me know your thoughts. I want to cut the flex section out. Then, weld a flange on both ends of pipe where the flex used to be. Then, get a flex pipe and weld flanges on both ends of that. Then bolt the flex in with my newly installed flanges. That way, I can replace these flex pipes easy the next time they fall apart again. Easy servicing and I can get good welds in there because I can weld the insides of the flanges to the pipe since it will be easy to get to instead of welding around the outside. Good idea?

#8

There is a short y-pipe joining the two cat sections on each side that has the small flex section in it. The one on the right, you can do with the engine in the car.
The one on the left requires the engine to be lowered so you can get to the nuts on the upper two bolt flange.

I changed my right one last month. I have the engine out right now to do the left along with a long list of other items that cannot be done with the engine installed.

#9

Thanks for that Eng92. Well, this sucks. Both of them are leaking. I guess I’ll pull the right side one out and weld in a new flex. The left side, I’m still up in the air about it. Seriously thinking about my flange idea. Or just getting a welder that can weld a new one while it’s still in the car because I can’t weld that up.

#10

Hey Justin, or anyone else who might know. I took pics of the inside of the manifold and it all looks good, I think. I don’t know how to attach pics here but I have pics. All flaps seem to be there. But, it does look pretty nasty in there. Is it advisable to open up the manifold to clean it out? Or is it asking for problems later on down the line? I can reseal it with some permatex high heat copper gasket stuff. It’s like rtv. But I don’t know if I will be doing more bad than good by trying to open it for a cleaning. Anyone have any input?

#11

Opening the manifold up can be quiet a pain. More so putting it back together!
Justin posted up a while back that when it removes you can use a basic style of cleaner - spray it in let it soak and then hose out. He said simple green which is a natural based degreaser. Of course you want it to be safe on plastics. Let her dry before reinstalling

#12

Lol yea I tried to open it last night. It would not come apart. I banged it with a flat head a little but didn’t want to mess anything up so I gave up and put the screws all back in. So pouring simple green in there should work? I’ll do it tomorrow! Thanks for the tip!