A8 Valve Cover Gasket Replacement Procedure
03-28-2002, 05:08 PM
#1
A8 Valve Cover Gasket Replacement Procedure
DO YOU NEED NEW VC GASKETS?
Does yout A8 smell "oily" a few minutes after you start it up? Does your garage smell like a Jiffy Lube?
If so, there's a good chance one or both of your valve covers are seeping a little. You can check by opening the hood of your car, starting the engine from cold, and letting 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, its probably valve cover gaskets.
If things start smelling, but the whiffs of smoke are either under the car or nowhere to be seen, check the transmission final drive seal (See hisport Post #13 for replacement procedure). It leaks onto the LH cat.
The VC gaskets are about $30 each. I suggest you replace both sides ($60 the pair;P/N 077 198 563. AutohausAZ.com 1 800 240 4620 is a good source for these and other OEM Audi parts)
Paul W is posting snapshots of this procedure to his Yahoo Audi Website, just FYI.
Figure two hours if you work slowly and fastidiously. If you're at all handy, this is an easy job; just keep everything clean and go gently. Look through the procedure for the few tools and materials that you will need. Great time for replacing spark plugs, if they're needed. Use only factory Bosch plugs - they're good for about 50K mi.
2. A8 VALVE COVER GASKET REPLACEMENT PROCEDURE
A. Pull the engine plastic.
* Side pieces first, then center. Two 6mm allen screws each.
* Loosen big intake hose clamps; remove hose and set aside. Stuff a paper towel into both openings (throttle body on engine and mass air sensor on air cleaner housing)
B. Remove the spark plug coils
* Each plug has a coil. Each coil is held in place with two 6mm screws (10mm hex head)
* Remove all 16 screws. Gently remove each coil, pulling straight up, starting at the front of the motor. Remove the coil wirng from the black plastic wire trough as you go
* Place the LH bank coils and wires up on the firewall at the rear of the engine. Gently: don't
drop or bang the coils. Place the RH coils and wires off to the right of the valve cover - they are held in a loose string by connections at the RH front of the motor. Remove spark plug plastic troughs (two 6 mm screws each bank. If you choose to replace plugs, blow out any grit in plug wells after breaking each plug loose.
C. Remove Valve Covers
* Remove VC breather hose at front of motor. It simply connects the valve covers together. Just gently push the hose off each VC 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 papertowel under the fittings to catch any gas drips - though there should be little if any.
* IMPORTANT! 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 aroud the covers carefully
* Remove the VC fastners. Four 6mm hex head 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 (they're different)
D. Clean and Regasket
* 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. Now, 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 VC. After allowing 5 minutes or so of set up, fit the new gaskets to each valve cover. Thet only go on one way; both center and edge gaskets.
* Now, 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 VC. This will fill in any gaps. Just a very little bit is needed; four places on each VC
E. REASSEMBLE
* Pop the covers back on, first making sure all the hoses and what have you are out of the way, and that the cylinder head sealing surfaces are perfectly clean and dry. Check that the VC screw holes are not full of oil or solvent
* IMPORTANT! Run up the six valve cover screws just fingertight, 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 ft lbs
* Reinstall front engine hose, fuel hoses, and coil wire troughs. Blow out the spark plug wells before fitting the coils. Tighten coil fastners to about 12 ft lbs
* Replace engine plastic, then remove paper towels and install breather hose, lining up index marks and clamping securely.
* You're done.
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.
After examining my old gaskets with an eye loupe, I believe they were leaking on the valve cover side, perhaps due to the unmachined (rough) edge. This is why I suggest using a sealer on this surface. The silicone sealer at edge junctions on the cylinder head side is factory.
Hope this helps.
John
Does yout A8 smell "oily" a few minutes after you start it up? Does your garage smell like a Jiffy Lube?
If so, there's a good chance one or both of your valve covers are seeping a little. You can check by opening the hood of your car, starting the engine from cold, and letting 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, its probably valve cover gaskets.
If things start smelling, but the whiffs of smoke are either under the car or nowhere to be seen, check the transmission final drive seal (See hisport Post #13 for replacement procedure). It leaks onto the LH cat.
The VC gaskets are about $30 each. I suggest you replace both sides ($60 the pair;P/N 077 198 563. AutohausAZ.com 1 800 240 4620 is a good source for these and other OEM Audi parts)
Paul W is posting snapshots of this procedure to his Yahoo Audi Website, just FYI.
Figure two hours if you work slowly and fastidiously. If you're at all handy, this is an easy job; just keep everything clean and go gently. Look through the procedure for the few tools and materials that you will need. Great time for replacing spark plugs, if they're needed. Use only factory Bosch plugs - they're good for about 50K mi.
2. A8 VALVE COVER GASKET REPLACEMENT PROCEDURE
A. Pull the engine plastic.
* Side pieces first, then center. Two 6mm allen screws each.
* Loosen big intake hose clamps; remove hose and set aside. Stuff a paper towel into both openings (throttle body on engine and mass air sensor on air cleaner housing)
B. Remove the spark plug coils
* Each plug has a coil. Each coil is held in place with two 6mm screws (10mm hex head)
* Remove all 16 screws. Gently remove each coil, pulling straight up, starting at the front of the motor. Remove the coil wirng from the black plastic wire trough as you go
* Place the LH bank coils and wires up on the firewall at the rear of the engine. Gently: don't
drop or bang the coils. Place the RH coils and wires off to the right of the valve cover - they are held in a loose string by connections at the RH front of the motor. Remove spark plug plastic troughs (two 6 mm screws each bank. If you choose to replace plugs, blow out any grit in plug wells after breaking each plug loose.
C. Remove Valve Covers
* Remove VC breather hose at front of motor. It simply connects the valve covers together. Just gently push the hose off each VC 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 papertowel under the fittings to catch any gas drips - though there should be little if any.
* IMPORTANT! 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 aroud the covers carefully
* Remove the VC fastners. Four 6mm hex head 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 (they're different)
D. Clean and Regasket
* 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. Now, 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 VC. After allowing 5 minutes or so of set up, fit the new gaskets to each valve cover. Thet only go on one way; both center and edge gaskets.
* Now, 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 VC. This will fill in any gaps. Just a very little bit is needed; four places on each VC
E. REASSEMBLE
* Pop the covers back on, first making sure all the hoses and what have you are out of the way, and that the cylinder head sealing surfaces are perfectly clean and dry. Check that the VC screw holes are not full of oil or solvent
* IMPORTANT! Run up the six valve cover screws just fingertight, 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 ft lbs
* Reinstall front engine hose, fuel hoses, and coil wire troughs. Blow out the spark plug wells before fitting the coils. Tighten coil fastners to about 12 ft lbs
* Replace engine plastic, then remove paper towels and install breather hose, lining up index marks and clamping securely.
* You're done.
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.
After examining my old gaskets with an eye loupe, I believe they were leaking on the valve cover side, perhaps due to the unmachined (rough) edge. This is why I suggest using a sealer on this surface. The silicone sealer at edge junctions on the cylinder head side is factory.
Hope this helps.
John
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