Sludge and the Audi/VW 1.8 L Turbo Engine

They weasel out of the warranty even though they erred by specifying 10,000+ mile oil changes with mineral oil, a small oil filter and low oil capacity.

So You Think You Have Sludge

• Look Under The Oil Filler Cap
• Installing an Oil Pressure Gauge

My Dealings with My Audi Dealer

• Admitting you have a problem (They won't want to)

Removing Sludge From the Audi 1.8T Engine

• The Audi Sludge Letter
• The Audi Sludge TSB
• Valve Cover and Head Cleaning
• Oil Pan, Pump, and Suction Screen
• Crankcase Ventilation and Other Engine Peripherals

Post Sludge Precautions

• Frequent Oil Screening
• Oil Filter Autopsy   Mahle
• 2nd Autopsy   Bosch
• 3rd Autopsy   Audi

Other Documentation

• My rants in groups along with the replies
• Other words

So You Think You Have Sludge

   Look Under The Oil Filler Cap

This shows the view since my engine was cleaned.

There's no need to post a before shot because it would be all black. If you doubt that take a look at my valve cover as it was.

Another simple test is to put your drained oil through a paint filter and check for carbon particles.
 

   Installing an Oil Pressure Gauge

Clicking this image will take you to Bentley's web site.

I can't be sure that this is the best site, but it showed me when my pressure was low and it shows my pressure within the proper range since the sludge repairs. It is also at least as accessible as any other spot. I moved the radiator overflow tank aside to get what was at best limited access. 

I went with a cheap mechanical gauge with nylon tubing, thinking that I could upgrade later if necessary. The mechanical gauges are said to be more accurate and to have quicker response than the electrical senders. I figured there was no reason to look for copper line based on the warnings I had heard about vibrations eventually cracking it. I already had 6' of 5/8" i.d. windshield washer hose around the house so I stuffed the nylon hose in that. It kinked a little when I tried to push too much at once. Pushing in no more than 3/4" at a time worked well. Once it was in the rubber hose it behaved well during the install.

To gain access for the install I removed the plastic engine cover, the weather stripping that holds the long plastic cover over the rear of the engine bay, and I pushed the coolant reservoir out of the way. Only one screw to remove the reservoir, but the plastic prongs that go into the metal tabs on the firewall were hard to work free (pulled up and towards the front on the reservoir).

I used ratchet extensions and a swivel to get the plug out and put in the sender. Then I used a small crescent wrench to fasten the hose with its compression fitting. After dropping wrenches and having to fish them out of the belly pan it finally dawned on me that I could tie a string to the wrench.
 
 

This is viewed from above from the driver's side looking through the intake manifold. There is nothing enjoyable about manipulating parts and tools down there. You should start this part of the installation first. If you give up there's no sense in having a gauge installed in the cockpit. You can see the brass pipe fitting that screws into the oil filter housing and the brass compression fitting nut that secures the white nylon hose (which is just barely visible before being blocked by the U-shaped hose in front). I wish I had known that the sender had a tapered pipe thread. It would have spared me from an unnecessary trip to the auto parts store thinking it had either defective or incompatible threads. It didn't take much tightening to make it leak proof and I don't think you'd want to over do it as the filter housing looks like it's made of aluminum.

 

There are two firewalls. On the engine side I peeled back the weather stripping and ran the hose above an oblong grommet for two metal lines. The hose is marked in the image below. It then runs to the left from there between the two firewalls. 

 

On the inside I cut a hole through an unused round grommet shown in close up in the inset. I mounted the gauge on the black plastic. I used the full 6' of hose. The gauge is partially blocked from view when I am driving so that I can't read the number at the top of the dial. I can still see the needle though. There is a chance of breaking the line when getting in and out of the car. That would cause a lot of oil to spill if the engine were running. (At over 20 psi I'm guessing it would be like a super soaker water gun). I plan to secure a larger piece of hose with electrical tape to cover the transition between the coupling nut and the rubber hose. Another location for the gauge Also, some like to remove the center vents and install there.

Pressure Specs

Bentley CD says:

19 psi @ idle
50-65 psi @ 2000 rpm

20 psi @ idle
45 psi @ 2000 rpm 

At the time I wrote:

I'm thinking the 45 is close enough. Anything to worry about? -- This car had its oil pump replaced at 25k miles and has had oil light warnings since. I'm thinking that now with the proper oil, filter and interval specs the sludge problem has been reduced to one where the sludge is gradually being cleaned up and is clogging the filter. The dealer has my next oil change interval at 2000 miles. [7/19/2005]

1300 miles since the oil change and now my pressure won't get above 30 psi (2 bar). [7/25/2005]

The Audi Sludge TSB (Technical Service Bulletin)

According to the TSB the state of the camshaft bearings is the test to determine if the engine should be salvaged. Apparently this is because these bearings are at the end of the pressurized oil flow path. So, it is assumed that if they are acceptable the rest of the engine is likely to be as well.

It was easy to tell from the sludge around the bolts that my dealer removed only one bearing cap before telling me that my engine was salvageable.

One of my intake camshaft double bearing caps.

Having performed an oil filter analysis after following the TSB's cleanup procedure, I feel the TSB cuts a big corner when specifying that the head should be scraped in place. To do it right the head should probably be pulled and soaked in solvent as shown on this Toyota engine. There is too much sludge left after scraping the head. With frequent oil changes that shouldn't be a problem. The oil gauge will let me know if the pick up screen is becoming clogged again.

Valve Cover and Head Cleaning

Removed from the wells between the spark plugs.

The Audi dealer wanted $3400 to perform the sludge TSB work or $300+ to replace the valve cover so that I could take it elsewhere. So I had it towed home and began the work myself.

Well since the folks at Audi were kind enough to remove the cover for me I started with it. This stuff is hard to remove. I soaked this in various solvents, break parts cleaner, engine degreaser... I still needed to brush it and it still had some varnish on it when I finished. You could try soaking parts in carburetor cleaner overnight. On the areas not immersed in oil such as the valve cover the sludge was hard and flaky or like undercoating. On dead spots filled with oil the sludge was soft like that on the screwdriver above. Audi does not recommend using engine flush chemicals and based on my efforts I'd say they would be useless on the hard stuff. I have also heard that they can cause oil seal leaks.

This is part way into the cleaning. One of the double camshaft bearings has been removed and cleaned. The wall connecting the spark plug wells has been scraped, though some brownish varnish remains.

Sealants

The Audi sealants prescribed by the Bentley manual are exorbitantly expensive: about $70 for one at my dealer that I assumed must be for a vat of the stuff for the pros, but no, it was for something smaller than a toothpaste tube. It calls for sealant AMV-174-004-01 for the corners of the valve cover, AMV 188 001 02 for sealing the end bearing caps (probably anaerobic sealant typically called for in Haynes manuals and that auto parts store employees scratch their heads on), and silicone sealant D-176-404-A2 to make the oil pan gasket (there is no preformed gasket). 

I used Permatex Blue RTV sealant and sprang for the Ultra at $4.44 and I haven't had any oil leaks. I did have an oil leak after this repair where I couldn't find the source. This stopped when I replaced a bleeder valve that had become clogged which was probably pressurizing the crankcase (not sure if that would be the correct term/location) and blowing oil past a seal.

For step by step directions on valve cover removal and some views of a healthy 1.8T see the tech article at www.audiworld.com

Oil Pan, Pump, and Suction Screen

This does not attempt to explain all the details involved in removing the oil pan. It is only to show those special considerations for the amateur mechanic. I strongly recommend getting the Bentley Manual CD. It has the proper torque specs and tightening sequences as well instructions for lowering the subframe without messing up the alignment.

To remove the pan the subframe must be lowered (actually tipped down in the front; the back is still secure). The subframe supports the engine. Once that is lowered the only thing supporting the engine is the transmission, so the engine has to be supported while removing the pan.

Who has an engine hoist?

I didn't and I wasn't about to buy one. I decided that I would be safe with 3, 2x10s and tie-down straps with a 1000 lb. working load rating and 3000 lb. breaking point. I mistakenly purchased 2x12s which turned out to be a good thing because the length of the strap below the ratchet is fixed and rather long for this application. This thing is heavy. I used some scrap pieces on the ends and center to connect the three beams. I could barely set it in position by myself. I have since decided that with the 2x12s I could remove one of the outer boards.

The Bentley manual doesn't make clear the location of the rear engine eyelet for lifting. It is a black metal plate with the hole hidden by a plastic sleeve that supports a hose.

Note the 2x2s used on the inner edges of the fenders. I notched the beams slightly (too much and the beams would have touched engine parts) with a circular saw to fit over these. I may have placed cardboard under the 2x2s.

Note the weather stripping peeled back and the coolant reservoir tank still connected, but placed aside. I used a scissors jack with a piece of radiator hose on top. I also added a second tie-down (not shown) for peace of mind.

The manual says that the lock carrier must be placed in the service position. I didn't do this. There might have been more room to remove the oil pan if I had. Beyond that the only reason I can see to do so is to easily reinstall the snub mount at the front of the engine. Perhaps this is different on a car with a manual transmission, but with my automatic snub mount I was able to push on the base to compress the rubber sufficiently so that the bolts could be reinserted.

Place tension on the engine. Stop before it begins to lift.

There's a special tool to remove the two pan bolts at the end of the transmission (#T10058). The flywheel has a notch in it to gain access to the bolts. I managed to remove them with an Allen head socket placed lightly (not snapped in) on a swivel extension. It would be easy to round out the bolt this way. I noticed that most bolts break free and then turn rather easily. A bolt that feels like it's turning slowly under a lot of force is probably being stripped.

Don't mar the mating surfaces of the pan when trying to remove it. You can tap it lightly with a rubber mallet. It won't seem like anything is happening and then it will break free. 

To remove the oil pump the sprocket must be removed. You'll need a large Torx (star bit). My basic drill set didn't have one large enough. I think the size needed is a T40.

I probably needed only a new suction tube, but this job is so time consuming that it seemed pointless not to spend $100 for a new pump. I thought I was going to get a knock off, but the pump had Audi/VW and the proper part number on it. The problem was that it came with a much longer spout than the original shown below. I think it must have been intended for use in the transverse VW engine, a design which allows for a larger pan. So I had to bite my lip and buy a spout from the dealer.

The yellowish bits are fragments of the oil-stained, white RTV sealant used on the pan when the dealer replaced the pump at 24,000 miles. The majority of the blockage was due to the hard carbon bits as well as some softer sludge. Since it is black it's hard to see in the photo, but most of the screen's openings had some piece jammed in and the tapered edges were packed with sludge. All my attempts to clean this part by soaking in solvents and Drain-o and by spraying solvent with an extender placed right at the back of the screen were futile.

The oil pan had hard sludge that got worse higher up on the walls of the pan. I got it spotless using a steel wire brush wheel on a rotary tool. I tried a softer brass brush initially, but it disintegrated too quickly.
 

Crankcase Ventilation and Other Engine Peripherals

According to the dealer technician you should definitely replace the items in red. The one on the left is listed in the ETKA as a bleeder valve (#06B103245, good price here and here). The mechanic at the Audi dealer referred to it as the PCV valve. My Audi has a 3-way valve (some are straight so check your part no.; might be 035103245A ...or G?). I posted my story about this part along with the error codes caused by it to AudiFans. 

Piston blow by pressure has to be relieved by the bleeder valve. If it clogs the pressure will escape through oil seals causing leaks. "Flow is normally from both 2 & 13 toward 5, then 6, then out into the intake manifold. Under boost, flow is from 2, past 5, to 13, then on through 15, where it enters the intake system pre-turbo. Part 6 (The PCV Valve) is also a check valve that keeps boost air from entering the PCV system."¹

The other part (circled at right) is the vacuum suction jet pump (or brake booster suction jet pump, #058133753B, best price I found). I finally got around to checking this part and found that it was perfectly clean inside. (It actually broke apart at the seam when I was trying to remove the hoses) There are alternate arrangements to that pictured above depending on VIN# (AMB up to ...8E*3*100001) where this part is connected with a hose directly to the PCV. That may be the case where clogging of this part would occur.

If you try to clean the tubes and hoses be aware that the metal tubes are painted black inside, so use some care in selecting solvents or other cleaning agents.

Post Sludge Precautions

I aim to keep it that way. 
 

Frequent Oil Screening

I couldn't bring myself to change $25 in M1 0W-40 oil every few hundred miles so I bought a pack of paint filters to strain my drained oil so that I could reuse it.

Here is what I got 1200 miles since the desludging and 900 miles since the previous straining:

1400 miles since desluge and oil change / 200 since straining:

 

 Oil Filter Autopsy (Mahle)

Here are the innards of the Mahle filter (#068115561) I just took off my A4 1.8T at 43,000 miles, 1400 miles since cleaning  the sludge according to the Audi Sludge TSB. This was the first filter used since cleaning the engine. Though, if I remember correctly, I ran the engine after the repair and then replaced the filter with this one.

Filter parts:

I cut it open using several of those cheap rotary tool cut-off wheels that 
disintegrate. Wear safety glasses when using those. 

Not much to it. A spring holds the core and gasket against the open end. The gasket seals the incoming oil from the flow out the center and keeps oil from draining back into the pan when the engine is stopped. There is a spring loaded gasket at the other end that will allow oil to bypass clogged paper if the pressure differential within the filter gets too high.
 

The filter paper stretched out:

Used a hand saw to cut it out

I feel the TSB cuts corners, to do it right the head should probably be pulled and soaked in solvent instead of scraped by hand in place.

Hopefully, next time this won't be so bad. It actually doesn't seem that bad now considering the amount of crud I removed from the head.
 

A fine, metallic dust on the closed end that I hope would be typical of any engine (this may have been the result of the thick cut off wheel I used initially to cut the oil can):
 

People make a lot of fuss over filters. Obviously you want something of sufficient quality that the seals, gaskets and paper work as intended, but none of that should be hard for stuff as simple as that. The main difference I can see is that larger is better (though there is no reason to oversize given a specified change interval and engine). This filter probably has at least twice the surface area of the originally specified filter. That means the same paper should be able to hold twice as many impurities before clogging. 

The only other factor is the type of paper. Some are paper (cellulose) and some are synthetic. Paper choice will determine the largest sized particles that are allowed to pass through to the bearings. There are some drawbacks to blocking small particles. The paper will clog sooner. If that happens before it is changed then oil will bypass the paper altogether allowing even the large particles to reach the bearings. It would also be interesting to know if thick, cold oil bypasses the paper to some extent and whether this would occur even more so with a paper of a finer mesh.

 

2nd Autopsy (Bosch) (#72174) After another 1000 miles it looks better: less carbon and no metallic powder.

 

3nd Autopsy (Audi) After another 1700 miles even better (#068-115-561B). The Audi and the Mahle have similar paper. The Bosch and Audi use a leaf spring instead of a coil spring. The others use a metal strip to join the two ends of the paper together while the Audi is glued.

Here is another analysis with information from those with some experience. Quoting from that page:

Oil Filter Media Condition

Non-turbocharged: Tan colored, small amounts of hard carbon. Filter paper should not be brittle. Dark filter media without significant hard carbon means the filter has not been changed often enough. Dark filter media with significant amounts of hard carbon indicate high oil temperatures. Suspect compression blow-by, or poor engine baffle.

Turbocharged: Tan to dark colored with more amounts of hard carbon. If filter media is brittle then filter should be changed more often or oil temperatures should be reduced.