Valve Cover Gasket Replacement
If your A8 smells oily a few minutes after start up, or if your garage smells like a Jiffy Lube, then it could be the valve cover gaskets leaking. If the smoke is coming from under the car, you might also consider the transmission final drive seal which can leak onto the left hand catalytic converter. To check if it is your valve cover gaskets, open the hood of your car, start the engine when cold, and let it idle for a few minutes. If a few whiffs of smoke start appearing around the sides or back of the engine after things warm up, it’s probably the valve cover gaskets.
Make sure you replace both valve cover gaskets at the same time. You might want to consider replacing the spark plugs at the same time. Check out our Spark plug replacement tutorial!
The part number is 077 198 563.
Tools Required
- Screwdrivers
- Metric allen head wrenches
- Metric socket and wrench set
- (2) 17 mm open ended wrenches
- (1) 14 mm open ended wrenches
- Blue paper towels to keep things clean
- Brake cleaner
- “Brush in Can” gasket sealer such as
- Permatex Aviation or Loctite High Tack
- Auto silicone sealer such as Dow
- Permatex or Loctite
Procedure
Remove the engine plastic
Pull the side pieces first, then the center piece. Loosen intake hose clamps; remove hose and set aside. Stuff a paper towel into both the throttle body on engine and mass air sensor on air cleaner housing.
Engine plastic bolt locations
Remove the spark plug coils
Each plug has a coil. Each coil is held in place with (2) 6mm cap screws (10mm hex head). Remove all 16 cap screws. Gently remove each coil, pulling straight up, starting at the front of the motor. Remove the coil wiring from the black plastic wire trough as you go. Place the left hand bank coils and wires up on the firewall at the rear of the engine. Gentle, don’t drop or bang the coils. Place the right hand coils and wires off to the right of the valve cover - they are held in a loose string by connections at the right hand front of the motor. Remove spark plug plastic troughs (two 6 mm cap screws in each bank). If you choose to replace the plugs, blow out any grit in the plug wells after breaking each plug loose.
Each coil is bolted in place, fuel lines are above and on the left, engine throttle body is stuffed with rag, and valve cover breather hose is on the front end of the valve cover.
Remove Valve Covers
Remove the valve cover breather hose at front of motor. It simply connects the valve covers together. Just gently push the hose off each valve cover fitting. You can reuse the clamps by just leaving them in place. Push other hoses, etc. out of the way. There will be a couple of them lapping over the center edge of each valve cover. Just tuck them in with the injector rails toward the intake manifold. Remove the two EFI supply fuel lines. These are situated at the rear of the RH valve cover. Use two wrenches on each fitting (17mm & 17mm; 17mm & 14mm). Doing this will “backup” the stationary fitting, while you break loose and remove the rotating fitting. Place a paper towel under the fittings to catch any gas drips - though there should be little if any.
Blow off any loose grit or dirt from around the valve covers. This stuff tends to accumulate under the engine plastic, and you don’t want it inside your engine when the valve covers come off. Use a compressor, bicycle pump, aerosol brake cleaner, paint brush - your choice, but clean around the covers carefully.
Remove the valve cover fasteners. Four 6mm hex head cap screws around the edges; two 6mm allen screws down the middle. Pull off the valve covers. You may need to bump them gently to initially dislodge, but no prying or banging please. Note right and left because they’re different.
Backside of valve cover and replacement gaskets
Engine with removed valve cover
Clean and Regasket
When replacing the gasket, ensure the valve cover and cylinder head are completely cleaned before installation of new gaskets.
The A8 valve covers are beautiful aluminum die castings. The gaskets themselves are molded neoprene in two pieces for each bank: one to seal the spark plug holes, the other to seal the valve cover gasket edges.
Pull off the old gaskets and discard. Clean the valve cover gasket surfaces with turpentine, solvent, or aerosol brake cleaner. Wipe clean and dry with a paper towel. Clean the mating cylinder head surfaces. Aerosol brake cleaner and a toothbrush work well for this. Be sure to remove the dried silicone sealer located at the front and back of each head. Wipe dry.
Using a “brush in can” gasket sealer such as Permatex Aviation or Loctite High Tack, sparingly brush sealer all around the (rough) edge of each valve cover. After allowing 5 minutes or so of set up, fit the new gaskets to each valve cover. They only go on one way; both center and edge gaskets.
With the valve covers ready to go back on, first smear a dab of automotive silicone sealer at the front and rear sharp edge sealing valleys of each valve cover. This will fill in any gaps. Just a very little bit is needed; four places on each valve cover.
Reassemble
Put the covers back on making sure all the hoses and what have you are out of the way, ensure the cylinder head sealing surfaces are perfectly clean and dry. Check that the valve cover screw holes are not full of oil or solvent.
Run up the six valve cover screws just finger tight, then gradually work a circle around the six screws 1/2 turn at a time. This will evenly draw down the cover, uniformly compressing the gaskets. Tighten to about 18 lb-ft of torque. Reinstall front engine hose, fuel hoses, and coil wire troughs. Blow out the spark plug wells before fitting the coils. Tighten coil fasteners to about 12 lb-ft of torque.
Replace engine plastic, then remove paper towels and install breather hose, lining up index marks and clamping securely. Drive your A8 for a couple of days to burn off the oil and cleaner that got slopped around during the procedure. It should then be oil tight and odor free.
Source: www.audipages.com
Authors: John Griffin and Paul Waterloo