At the risk of posting more than anyone may want to read I am copying a post I made to the W8forum with a couple modifications:
I am convinced the application of 12v to the cam adjuster solenoids is the proper thing to do. If it is sludge/varnish/oil deposits of some type then the AutoRX/Seafoam/oil flush procedure will be helpful. If the fine stainless steel wire screen material has come loose and is jamming up the solenoids or cam adjusters then only physical cleaning or knocking them loose will help. That is where the "electroshock" therapy comes into play but is by no means the final resource you have. I would like everyone to hold on to their hats until I get a chance to examine my W8 that is showing a Check Engine Light with the P0011 code.
If you are interested, here is a technical explanation of what I have seen so far:
1) Internal engine cleaning is good. Do not panic and overdo it though because if you damage bearing surfaces there is no recovery from that.
a) You can do a short engine flush. This is the 5 minute (Gunk brand) to 30 minute (Amsoil brand, Seafoam, etc) flush you do right before an oil change. I prefer the longer, milder 30 minute flush. In any case, follow the manufacturers directions and remember; the W8 holds about ~10 quarts oil so you will have to use twice as much flush as would be used on a "normal" 5 quart oil capacity motor. This is a good thing and is relatively cheap. $5 to $15 plus the oil change.
b) You can do the dealer's machine flush that especially Toyota and VW/Audi have developed for their particular sludge/varnish/deposit problems. This may be a good thing too and may fit into your maintenance program depending on how "stuck" your solenoids/adjusters are and what your next maintenance steps will be. This treatment was around $125 last time I checked. The only reservation I have is that this procedure flushes gunk buildup that is laying around the inside of a motor
(like a gear driven camshaft Toyota motor) but will not likely get inside the cam actuators which is is exactly where we need it.
c) You can do the long term internal cleaners like AutoRX, Seafoam, Rislone (?) and others (help me out here). I only know about AutoRX and see it as a very good thing. You will probably spend an extra $50 to $200 depending on how many treatments you choose to run through.
d) By the way, when you are all done with the flushing programs and are set to go back to a regular drain interval I recommend full synthetic oils and even then I would stay with Ester based synthetics like Amsoil or Redline because Esters have built in self cleaning properties (they are a polar molecule). I don't know off hand what other Synthetics are Ester based.
2) In addition to the chemical cleaning steps above you will want to do a physical exercising of the two affected parts; the hydraulic cam adjusters that are bolted to the ends of the camshafts and the electrical solenoids that control the cam adjusters by regulating the flow of oil pressure to them. Here is a great training document that shows how the motor is built and how the adjustable cam stuff works. Look on pages 29 & 30:
Here is a picture of the actual adjusters and solenoids on a opened up W8. Look at post date of, 20-Jan-2009 at 21:45
a) I am not a fan of exercising the solenoids using a scanner (Volkswagen Auto Group Communications link or VAG/COM) because that is what the car's computer (ECM) is constantly doing all the time while you are driving. Might as well flush the oil and just go out and drive the car. One exception I can see is if your mechanic wants to sit there and drive the solenoids back and forth with a VAG/COM while the motor is being flushed.
b) A far better method is to drive the solenoids with 12v from the car battery which is far stronger than the 5v it normally sees from the computer. This is a good thing because where it may have been stuck with only 5v from the computer, 12v has a much, much greater chance of getting them loose if that is indeed the problem. It is simple (there are 2 wires coming from each solenoid) and it is easy to know if it is working. You will hear clicking as the plunger in the solenoid is moved when you apply and release voltage. If not, try reversing the voltage back and forth numerous times until applying 12v extends the plunger with a click and releasing the 12v produces a click from the built in spring retracting the plunger. Applying 12v has been proven to be safe to the solenoids by the Swiss tech that first explored and published this procedure. If the solenoids do not respond you can always remove the valve covers, pull the solenoids out and clean the plungers and their bores by hand. Pulling the valve covers is way better than pulling the motor.
c) If the hydraulic actuators are stuck because the solenoids are moving freely but you are still getting cam codes then you have three things you can do:
i) Drive the car while the cleaners do their work(AutoRx, seafoam, etc). If there is some movement in the actuators and they are only a little gummed/varnished up then this will work. If the actuator is totally stuck then there is not going to be any oil flow into and out of the internal vanes and little chance that cleaners will help. If there are bits of torn out very fine stainless steel wire from what was previously a screen meant to protect this stuff, and it has totally jammed the actuators, then you will need to go to the next step and: (BTW, I have since learned that the stainless steel mesh screen is part of the solenoid body where it inserts into the head and surrounds the plunger portion of the solenoid)
ii) Remove the valve covers and twist the cams back and forth with a really huge pair of pliers until they twist freely. You can twist a lot harder on the cams with a huge pair of pliers than the oil pressure ever could. After removing the valve covers you need to remove the solenoids that are now sitting right there in the open so the oil control passages are completely opened up and not restricting the cam's movement. The intake should move through 52 degrees of motion and the exhaust should twist with only 22 degrees of motion. If they do not loosen up and twist freely even after you have twisted the cams back and forth with all your might until your hands have gone numb then:
iii) You will have to take the actuators off the ends of the cams, take them apart and clean them. Don't give up and remove the motor quite yet. I am going to dive into my W8 very soon and I have an idea of how to relax the cam chain tensioners so the actuators can be unbolted, taken out, taken apart and cleaned then reinstalled. I am determined to do this. BTW, if any of you techs out there are reading this and know of a tool or can give me a clue I would appreciate all your advise.
3) Do not let anybody scare you by saying there are bits of metal in the pan and your motor is ruined. The bits of metal is what is left of a fine stainless steel mesh that was a filter in the oil passage to the cam actuators. This debris will not hurt anything except the oil pump because the oil filter will capture it all if the pump does suck it up. If the pump is hurt a little switch to 10w-40 oil. If the pump got hurt a lot then drop the pan, replace the pump, clean and reinstall the pan and drive away happy! The cam chains and slide rails should go a minimum of 150k miles but I would expect more like 250k+ miles. No need to replace any of that. It is also my understanding that despite what people have written there is no difference between the old parts and new parts. There are no updated parts and I won't believe that until a tech shows me the old and the new ones side by side showing the differences or an official tech bulletin comes from VW. Parts guys and service guys don't count, they are there to sell parts and to sell service.
The W8 is a rock solid motor. The unfortunate problems caused by the stainless steel screen or the build up of sludge can be dealt with, I believe, without removing the motor and without the unnecessary replacement of any of the very expensive cam drive parts and housings. VW blew a great chance to develop a kit that any tech could use to secure the cam chains so the actuators could be removed and simply cleaned. I wish i had bought a W8 years ago so I could have made the kit then rather than now and helped more people. But here we are.
I did the same thing for the Cadillac NorthStar motor when the official Aluminum block/head bolt corrosion repair proved less than reliable and I made my own method of repair. We have dealt with the same foolishness from Toyota when they were replacing $1000 instrument clusters on their LS400 when all it needed was a 5 cent capacitor to make a 100% repair. We know that now.
Toyota, Cadillac, VW. No one is immune. So lets move forward with what we know right now and do the best for the customer even if it takes some effort. We could cut our time and expense on these W8's to 1/10 of what was previously accepted and there would still be more than enough work to do with all the sludged up Toyota's, leaky GMs and painful Honda timing belts out there to deal with. And as the great philosopher Forrest once said, "Any that's all I have to say about that".
Modified by billj3cub at 2:40 PM 2-28-2010