07 - S6 Coolant in oil - Complete Engine Teardown

A6 All/ S6 All
#61

Here is a shot of the front and rear crank seals along with the four plugs that go in the ends of cylinder head (front of engine) in line with the cams.

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Since I bought the car, the two on the left cylinder head were always slowly weeping oil just enough for airborne dirt to stick.

The Loctite 638 is a high strength retaining compound that is called out in ETKA under p/n D 154000A1

Here are the timing gears (original), new tensioners and bolts. The bolts are all torque to yield and had to be replaced. You will find that all of the 6mm bolts inside the timing casing are torqued to yield. It is the last place you would want a bolt to loosen up and fall out.

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Here is a shot of the parts installed.

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Note that the timing sprockets are not keyed onto the camshafts. You have to mark their orientation prior to disassembly and then reposition them the same way upon reassembly.

I still have to pretension the timing chains and torque the cam gears down properly. It is a lot easier to do with a second set of hands to hold the tension on the chains when the cam sprocket bolts are tightened.

For comparison purposes here are before and after shots of inside the LHS timing cover

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When I first looked at the above two pictures, I was a little concerned as the sprockets are in completely different orientations. I then realized that the first picture was taken without the cam locking clamp installed and the engine was not in the “TDC” position.

Incidentally, the “TDC” positon when the crankshaft locking pin is installed is when none of the pistons are at TDC. This makes it safe to install the cams as there is no danger of the valves contacting the tops of any of the pistons.

Next up will be getting the rest of the engine sealed up (for oil) so I will be able to pre-oil it.

#62

Work has been pretty crazy for the last few weeks so I have not had much time to move this project along substantially.

It is just as well as the rtv flange sealant takes forever to cure when the ambient air this time of year is so dry. I can keep the temperature in my garage at 20C (68F) when it is -20C(-4F) outside but the relative humidity is down around 20%. To cure properly, RTV sealants require moisture from the ambient air. I had to bring a humidifier into the garage in order to bring the RH% up into the 35 to 40% range for a few weeks so the sealants would cure properly. However, it is nice to work with rtv when the air is dry though as the working time is greatly increased. It is a nice change from trying to lay down sealant in the middle of August when the humidity is 90%+ and the stuff is skinning over almost as soon as it comes out of the tube.

I did manage to get a few items taken care of.

I torqued the cam timing sprocket bolts down with the assistance of one of my sons. A tension preload needs to be maintained on the chain while you tighten the bolt on each of the sprockets to an initial value. The cam clamps are then removed and a final tightening torque is applied to each bolt.

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After the final tightening, the crankshaft locking bolt is removed and the crank is rotated 720 degrees back to the “TDC” position. The cam clamps and crankshaft locking pin are then re-installed. All bolts should thread in freely confirming that the timing is correct. The cam clamps are then removed but the crankshaft locking pin is left in place to facilitate the installation of the drive plate.

The rear timing covers were then installed with new sealing rings at both ends of the internal water pipes that bring coolant into the ends of the heads. The pipes were installed into the rear timing covers using a press

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From my reading, these are known points of potential leakage although I saw no obvious signs that indicated this was the point that coolant was getting into my oil.

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Next up was getting the valves covers on with new gaskets. I replaced the bolts (w/ seals) on the RHS. The LHS cover was replaced about three years ago so I reused the original bolts.

Here is a shot identifying the valve covers and o-rings for the cam timing valves and position sensors. ETKA does not identify the o-ring for the position sensors as a separate part so I measured them up (12mm ID x 2mm c/s) and purchased them from a local vendor.

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Here is the oil filter base and seals along with the check valve and spray nozzle that are installed in the valley. I replaced the o-rings on those two components as well (12.5x2 for the spray nozzle and 21x2.5 for the check valve)

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Next up will be a little reconditioning of the injector harnesses before I install the IM.

#63

Keep up the great work eng92! Can’t wait tonsee everything squeaky clean when you’re done

#64

Exceptional work! Thanks again for documenting.

#65

Thanks for the words of encouragement guys. It will certainly be nice to get this completed and the vehicle back on the road

#66

After being cooked for the last twelve years in the valley of the engine, all of my injector connector housings had become so brittle that I had them all held in place with zip-ties.

Replacement harnesses are ridiculously expensive so I decided to go ahead and just replace all of the connector housings.

Here is a shot of one of each of the types that can be found on the two injector harnesses.

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Since I bought the car about three years ago, I have always had intermittent issues with the signal from the HP fuel sensor. Every once and a while, the engine would stutter for a split second.

The previous owner must have had the same complaint as I found a single wire outside of the factory loom going directly from the ecu connector to a second HP fuel sensor connector. The original connector was left attached to the factory harness but left disconnected in the valley. The person who did the wiring did a good job. All of the wires were terminated properly and the wire splices were tidy and sealed correctly. Initially, it did not make sense to me why I was still having this issue with the new signal wire run. Then I looked at the two wires for the sensor power supply and ground wire connections. The original two wires were left in the factory loom going from the black T14i connector back to the ecu. My guess is that when the tech was troubleshooting, they confirmed that the sensor power supply voltage and ground were good and all that needed to be replaced was the signal wire.

I did not like the look of this wire outside of the factory harness so I decided to replace the T14i connector. The tabs to release the secondary terminal lock were so brittle, they snapped off when I tried to release it so I ended up cutting the shroud off with a Dremel. When I exposed the male terminal pins, this is what I found. The three corroded terminal pins towards the bottom of the picture are 11, 12 & 13 which are the three for the HP fuel pressure sensor. Pin 13 is the most corroded one which just happens to be for the 5V sensor power supply. I am relatively confident that this has been the cause of my random stuttering.

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Moving along, I pulled three new wires through the injector harness and spliced on the female terminal pigtails from the connector that was previously replaced. I spliced some new 1.5mm MT2 male terminal pigtails onto the other end to replace the corroded ones

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With a little bit of harness tape, it should be almost as good as new at a fraction of the price.

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Here is a shot of the harnesses installed in the valley before the intake goes back on.

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#67

Will be checking this as well when I do the injectors. Great tips!

#68

Before I installed the intake, I figured it would be a good idea to put some oil into the pressurized part of the system to check for any leaks. In order to do this, I had to install the oil cooler which was the last component required to close up the lubrication system.

Here is a shot of the loose oil cooler and the two seals that often need to be replaced to resolve a common leakage issue that the engines of this vintage have.

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For pre-oiling, I deliberately left the oil drain plug out so I could gauge roughly how much oil was left in the engine.

I screwed a mini-air line fitting into the port normally occupied by the oil pressure switch. To this I connected an old brake bleeding bottle that I have which uses air pressure to force fluid out of the discharge hose which would normally connect to the master cylinder.

I filled the bottle with oil and set the regulator at about 15psi.

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The oil level started going down and after about 30 seconds, I saw a steady stream of oil coming out of a threaded hole in the block right behind where the starter sits.

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It is a small 10mm plug that I had forgotten that I had even removed last October when I tore this thing down. It is the same type of plug that goes in the end of the front water pipe that you remove when you drain your coolant.

So I installed that and continued adding oil. I fed about 3L into it before it started coming out of the oil drain plug hole. No other leaks were observed and I confirmed that I had oil feeding the cam follower bores for the HP fuel pumps.

I am certainly glad that I went through this oiling procedure beforehand and found the open port when I did. This plug is behind the starter. For those that are not familiar, the first step in the Bentley manual for removing the starter is “Remove engine”.

#69

good thing you did the pressure test!!! i would have died if i had gotten everything back together only to find an oil leak like that.

#70

Wow, was that a close call!!

#71

WOW seriously good find… WOW…so happy you found that sooner then later.

#72

Next up was installing the intake.

Here is a shot of the intake with spacers and gaskets/seals. The spacers require the use of longer bolts so I went with some 10mm longer ones and stainless steel washers.

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Here is the intake installed.

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I have never had any issues with vacuum leaks on mine but I remember the question of the intake bolt installation torque being brought up before by someone who was experiencing leaks.

The second gasket and spacer material adds compliance to this sandwiched connection. Therefore to achieve the same bolt clamping force, one would expect to have to tighten the fasteners beyond the specified 90 degrees after the initial 9Nm is achieved.

Of course I did not think of this until after I had the intake installed. If I were to go back and do it again, I would install the intake without the spacers and measure what the peak installation torque was for each bolt after the 90 degree tightening. I would use the average of these measurements as a basis for installing the intake with the spacers. Of course a bit of judgement and “feel” need to be used here. If you feel the bolts yielding and you are not reaching the expected peak, stop turning before it snaps as you need some stronger bolts.

Here are the throttle bodies and distribution housing with the associated gaskets and seals.

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One of the high pressure fuel pumps with seal and bolts identified

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Here is the water pump with seals and bolts. The pump still looks pretty new as it was just replaced last summer. The original one that came with the vehicle could not put through enough fluid volume to keep the engine from overheating.

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Here is the current state of engine assembly

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I have turned my attention now to the transmission as it has a few leaks and I want to do the filter and gasket while I still have it separated from the engine.

I have created the following thread which will detail that process

http://audirevolution.net/forum/index.php?topic=4938.0

#73

Great progress eng92! The jhm-supplied stainless steel bolts arent terribly strong and are liable to stripping with the hex head. For those who haven’t installed spacers, would definitely recommend a grade 8-equivalent fastener if possible (zinc plated or black oxide. Use lubricant to reduce required torque and as a corrosion protestant), and if you can get it in Torx drive, even better.

#74

[quote=“fenixgoon,post:73,topic:10248”]
The picture below shows the bolt heads on three fasteners.

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The far left is the grade 8.8 original factory manifold bolt. The middle bolt is the grade 10.9 factory bolt that I selected out of ETKA. The bolt on the right is the ungraded stainless bolt that came with the spacers.

I selected a different bolt because I do not like the use of hex drives on small diameter fasteners that need to be torqued to what would normally be beyond yield on a standard grade fastener.

I also would not recommend the use of lubricants on such a small diameter fastener if you are shooting for a torque that was specified for a non-lubricated fastener.

I found that the extra gasket and spacer added so much compliance that you had to make a few passes to get all the bolts to the initial 9 Nm tightening torque.

#75

Thanks for this ^^^ I sourced new bolts after stripping 2 of the bolts supplied with the intake spacers, and wasn’t even up to the 9nm. Just confirmed what I thought myself.

Going to wear out all the “thanks and keep it up” this is encyclopedia worthy information on this engine.

#76

The best part is the lay out of the parts and their respective fasteners, in quantity and their part numbers. Sometimes those bolts in the block and backside are sometimes hard to discern from just the exploded views.

#77

[quote=“Greg5OH,post:76,topic:10248”]
I agree completely. There was one very small round seal between the block and bed plate that took a while to find a number for. On the parts diagram, it was no where near its actual location.

#78

With the transmission now fully assembled, it was time to mate it up with the engine.

A couple of dowel sleeves are used to precisely align the bell housing to the engine.

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I found tapping them in using a 15mm socket was the easiest way to install them without damage. They are very thin wall and a soft material and you do not want to mushroom them out otherwise you will have more trouble pulling the engine and transmission together.

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The engine and tranny went together without incident. I suspended the engine from the shop crane and inched the transmission up to it on the motorcycle lift. Once they were a about an inch apart, I put a single long bolt through to steady the engine.

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The torque converter was then rotated so that one set of bolt holes was aligned with those in the drive plate at the opening where the starter mounts.

I then gave the engine a little “wiggle” to align the pilot on the torque converter with the bushing in the end of the crank and the two components slid together smoothly. Nine of the eleven 12 mm bolts were lubricated, installed and torqued to 65Nm. The remaining two bolts are for the starter and power steering pump which are yet to be installed.

Next up was bolting the drive plate to the torque converter. Six grade 12.9 bolts are used to clamp the two together to transmit all the torque that the engine makes. These must be replaced and are torqued to 85Nm

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Here are a couple of shots from different angles of the engine and transmission together

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That is it for this weekend as there are several other projects I have on the go which require immediate attention.

#79

guessing you’re in Canada? (wasn’t sure, but saw some Mastercraft sockets and the pizza pizza box)

#80

^the pizza pizza garlic dipping sauce is the best