DA8

Hey guys, old time member here. Owned my 2005 A8 and been on this forum since 2011, lots of great advice from stars here. Still my weekly driver, gonna run it till the wheels fall off. I've got 200,000 miles now.

I've had a leak for a while I want to tackle. The valve cover gaskets leak while sitting for a day or 2. Usually this is the case as I am riding my Ducatis during the summer. Then when I take the A8 out after she warms up the oil burns off the exhaust manifold and smokes off for about 20 min.

My idea is to replace the valve gaskets and rebuild the intake manifold in the same process. I have never removed the intake manifold or the valve covers. What I am looking for is advice on how to plan this service. What is involved with cleaning out and overhauling the intake manifold. It is the type that has the diaphragm that opens up under hard throttle. Do those inner rubbers need replaced? Note that I've never needed to replace my little plastic valve arms on the front of the engine like many have. My original plastic ones are still working properly. I don't know what to expect to find inside and want opinions.

And with the valve covers, what should I expect. Obviously I will buy new gaskets and seal the covers up good again, but what else? Valves have never been adjusted and I've never heard of anything about that with this car. Anything else I should do with the valve covers?

Thanks for all the great advice here.

mcs

I just had this exact service performed on my 04 4.2.

I would recommend the gaskets, plug tube seals, and on my car, I also changed the torque mount as it had split, and the throttle body gasket, which someone had used a cardboard gasket material instead of the 3 layer steel OEM one.

Having a good look at your chain guides for the camshafts and changing the cam tensioners if the car rattles for a second when cold started is a good idea, and there are a few seals at the back of the heads that would be changed while you are there. Lots of the time it is actually the little round plug at the back of the head which leaks onto the exhaust, not just the rocker covers.

Check the oil cooler for leaking coolant or oil also.

Mike

Aceler8

i highly suggest doing some searches and reading up on them. I did the valve cover gaskets a few years back and took pics and explained my pain points. I had to redo the driver side twice since the first time i sliced the gasket in half while installing. Overall, you will need to go through the wheel wells to get to the rear most bolts. You must cut through the heat shield sheet.

Once more advice....Be SURE you are straight when beginning to loosen the bolts. If not, they will strip easily. I stripped about 2 per side and it was painful.

MP4.2+6.0

Since you have a port injection 4.2, I would likely combine this job with both a tune up/spark plug change (no brainer/w you removing valve covers anyway)) and probably a timing belt job. With a 75-90K recommended interval (and it never having been longer than 105K along way to Audi reducing it a couple times), good chance it's due. More work, but timely unless recently done. Do you have service records? Not uncommon for owners to cheap out on the job and do belt only, so if no record of prior water pump, thermostat, pulleys etc, replace on the first job, I would do those too. Avoids breakdowns on road, and especially if never done the catastrophic belt failure that will effectively total the car value wise. If done in full post 140-150K miles from the records, you could defer til it's due.

From experience on both 4.2 (C5) and D3 W12 also look at front engine torque mount. Way easier to reach w/ some of the overlapping components already removed. Ditto on the more obscure coolant temp sensor, which is pretty low down in a water line in center back of motor. The latter is probably easiest if the intake is already removed. If not, I would probably defer until sensor acts up.

On intake, not convinced you should fool with it. I pulled mine on a 4.2 twice ONLY because I had to remove a cylinder head. It's port injection, so no reason to expect it (or intake valves) to necessarily need a lot of cleaning. BUT, make sure your intake manifold flaps are working--the vacuum driven ones. Mine froze up, first partially and then fully by 130K miles. That required a full manifold replace. It's not a great design longevity wise, so I have it in the "when not if" sort of bucket. Inspection though (with everything in place) is first step. If in order, I would probably leave intake alone and just run Techron fuel treatment through the gas and call it good. Up to two sequential tank treatments initially, then every oil change. I would definitely be tackling timing belt before any intake removal if belt is due and no obvious intake related repair work is separately needed.

DA8

Thanks Aceler and MP. I looked up that post about cutting the holes in the heat shield. Would the pivot torx help? I do have a good assortment of short throw torx from doing the SAI combo valves in the past. Is it just a matter of being careful to get a strait angle and good bite on the bolts?

MP as far as the timing belts, i did those 40K ago. Not sure I need to remove anything more than the top covers, not the whole front end like with a timing belt to get at the valve covers. The reason I was looking at doing the intake manifold was because I was assuming it had to be removed getting at the valve covers, but upon closer look it looks like I can remove one valve cover at a time without taking off the front end or the intake manifold. Maybe as you say I should just leave it alone. The intake is still functioning fine at 200K so far as I know.

Are my assumptions correct that the valve covers can be removed without removing the intake manifold or removing the timing cam gears?

Aceler8

Correct, you do NOT need to remove intake to remove valve covers. You will need to loosen the coolant tank on driver side, but that is no biggie.

MP4.2+6.0

At least on A6 4.2 port I had, valve covers came out with intake fully in place, and C5 was quite shoehorned in.

If you have not looked at the intake flap system to be sure it is really functioning, I would by 200K. There are no codes, lights, etc if something goes wrong. Just a power drop off either low or high if frozen depending on position. Broken actuator rods at the vacuum pods are a giveaway, but from my own experience it can be stuck even with those not breaking. Ditto on the torque mount. That is hard to access or see clearly, but the more that comes out in front passenger side area (like valve cover), the more you can see down there in the area. You are looking for any oozing brownish oil stains at or below the mount.

DA8

I did replace the torque mount 40K miles ago when I last did the timing belt and oil cooler pipe conversion to metal version. You can see them replaced in my signature photo.

maxandtara

DA8,

Wow, intake manifold hmm and valve cover...

Manifold - would involve the removal of the fuel injectors correct ?

• You want to put new seals on those fuel injectors then you reinstall them.
• Those fuel pressure regulators I don't know if they may need replacing but from an image I came across by accident, that thing has components that look like filters. (filters clog)

Bolts wear and removal

• Get some spare bolts
• All the bolts on the valve cover are suppose to be of stainless steel. Stainless steel is inert.
• Make sure the torx you use is not worn out..
• Do a dry run to check the play/wear on the bolt. This will give you an idea how many new bolts you may need.
• Removing the bolts, the tighter the torx bit to the bolt the better are you chances of not stripping. Use some paper, latex as a sleeve on your torx to reduce play.
• The gaskets of the valve cover bolts have rubber grommets they wear over time. Audi does not sell those grommets separately.
• There was a post before of a guy who reused the valve cover bolts. He asked for help because he still had a leak. So he had to redo the valve cover a 2nd time with new bolts. Leak is gone.

Bolts and Grommets

• Make sure you get the stainless steel bolts for the valve cover (minimize galvanic corrosion.) Valve covers still corrode anyway.....
• I bought a set of regular valve cover bolts (cheaper) and stripped the new grommets.

Heat Shield

• To gain better access to the cover bolts remove the heat shield. They are easily detached by removing those washer-like bolts (13mm ..if I am not mistaken). Cutting up your heat shield is another alternative.
• In hind sight, I would have covered the chassis bolt on re-instillation of the heat shield. The heat shield easily snags on the bolts. (Maybe cover the bolts with a stiff plastic liner so that the heat shield slides without snagging.)
• If you want to replace your heat shield, do a search on embossed aluminum heat shield.
• The audi heat shields look like 2 layers of that of those embossed aluminum heat shields.
  
  This is the nut that holds the heat shield in place there are 4 of them on each side
  
  left and right s heat shield
  
  View of corner bolt when heat shield is removed
  

DA8

Thanks maxandtara, great pictures. How difficult was it to get to those nuts for the heat shield to remove the heat shields?


Sounds like I need to order new head cover bolts and washers/gaskets along with the cover gaskets. Wonder if anyone knows the part number for those bolts and washers or if anyone knows just the spec of the bolts M?x?

Funny, not really hearing from anyone who rebuilt the intake manifold. Mine's not really having problems, so no need to fix what ain't broke. I am sorta abandoning that idea in lieu of just doing the head cover gaskets. I am also thinking of approaching it as one side at a time job.