All A8 owners complain about the oil cooler plastic pipe that breaks and leaks after 130k miles. It doesn’t matter if it’s 32V or 40V engine. The layout and mounting of both of the coolers are a little different, to me, the 40V (2000+ A8) is a little harder to do. If we plan to do it ourselves, we should buy the plastic pipe, rubber rings (2), rubber ring for the metal pipe (1), “8” shape ring. If there’s is oil/coolant mixed in the system, we may need the whole set of rings in the cooler. We did both 32V & 40V without needing the set of rings in the cooler because even with the coolant leak from the broken pipe, coolant doesn’t mix with oil in any of our cars.
The reason we should prepare because some stealers like Steven Creek Audi in San Jose would force someone to buy the whole set of rings and refuse to sell the “8” shape ring alone, Carlson Audi in Palo Alto would sell it individually. We ended up with $86 for the use of a few rings. Audi of America should advice the dealers to sell parts according to customers wants and not to force them to buy things they don’t want. The worst part is the part salesperson has no knowledge of the oil cooler system, he forced my brother in-law (who’s totally ignorant about cars) to buy ring that we don’t need, but didn’t recommend the ring that we actually need for the metal coolant pipe. Any who, like I always believe, “ignorance is a cancer, it will kill sooner or later”.
To remove the Oil Cooler on D2, both 32V or 40V like this one, the front end must be out, is somewhere on this website.
Remove Air Cleaner Housing
Air cleaner housing must be remove for easy accessing the cooler bolts.
Drain the oil and remove the oil filter. To remove the oil filter element, drain the oil from oil filter with 6mm hex wrench first, put it back and undo the housing next to pull out the filter element.
Remove the Alternator: Disconnect the Negative Terminal (black) battery (from the trunk), 3 wires going to the alternator 13mm, 8mm and a plug terminal. There are 2 bolts securing the alternator to the engine block, on this car, 1-13mm bolt and 1 8mm-hex bolt. In order drop the alternator, we need to remove the air cooler assembly also. The best is to remove the air cooler first.
Drain the coolant from front radiator and on the block if you want to replace the coolant completely. Now with the Air cleaner housing and the alternator is out, we have room to access the oil cooler, make sure all the tie-wraps on electrical wire are removed to move any electrical bundles that are in the way. There are 5 8mm-hex bolts, look at the picture below to see exactly where they are (this picture with the oil cooler actually out), there are 2 aluminum guide cylinders on the bolt #1 & #3 as we numbered ours. #3 is the hardest one to get to. We couldn’t get the 3 bolt hex in until we looked at our 32V set up. This is why we documented everything we did so we can use it later when needed. We found out that we must have some of the hex keys to help the job much easier than just a short socketed one. These long ones sure help the job a great deal.
In order the get this one in, we have to go under the car, lie down, put the arm over the passenger side bumper tube, from under the car, we can see the bolt, then we can see our hex going into the hex bolt. Make sure it’s in completely before breaking it out.
#4 Bolt next to the black coolant pipe.
#2 Bolt behind the oil filter block
#1 Bolt location
#5 bolt and #1 bolt are the easiest ones we didn’t have the picture for the bolts being taken out. On our experience, the oil sender unit on the oil filter should be removed before the oil cooler. It will help to clear the oil cooler out on the bottom of the car.
On the 40V, the black coolant metal pipe is routed to the outside. This one must be removed before the oil cooler can drop down from the bottom. While all bolts are out, wiggle the oil cooler counter clockwise and clockwise to break the seal, then pull the pipe totally out of the socket. Don’t forget to remove the 10mm bolt holding it in.
Wiggle and pull the oil cooler out to clear the aluminum guides from #1, #3 and the plastic pipe on top and slide it out from the bottom of the car. It will come out at the right angle.
Our #3 guide dropped down, make sure we have it and not damaged. #1 & #3 guides are important for re-installation.
The plastic pipe broke at the oil cooler and the block, we need to get a screw driver to carefully pry out all the old ring and broken pipe in both of them, clean them and get ready to install the new plastic pipe with rubber rings. Don’t forget to remove and put a new ring on the black metal pipe, in our case, we didn’t have one, we used the old ring.
Remove this little pipe for easy installation. Don’t forget to put it back before bolting all bolts on the oil cooler because when the oil cooler is in, there will not be any room for the screw.
Remove the “8” ring and place a new one there, rub some engine oil on it. Put 2 rubber rings onto the new plastic pipe and also rub some engine oil for easy installation.
There are 2 ways to do the plastic pipe, on the 32V, we install the plastic pipe with RINGS on the oil cooler first and push the other side in the block later. On this 40V, since the metal pipe is outside, we didn’t want to break it by accident while wiggling it up into the area, we installed it in the block first. Again, at the right angle, the oil cooler will come up from the bottom to the mounting area (which is above the oil case and the frame of the car.
Before installing the oil cooler make sure all the aluminum guides are there and the surface is cleaned.
Black metal pipe has new rubber ring and again Plastic pipe should have 2 new rubber RINGS
Again, is “8” shape ring new? Plastic pipe rubber rings (2) new? Black metal pipe rubber ring new? 2 aluminum guides are on #1 and #3 block? Plastic pipe installed on the block? If all yes, then we are ready to install the oil cooler.
In order to align and fit the oil cooler correctly and easily, the black metal pipe must be in FIRST.
While everything is still loose, install the skinny little black pipe back to the oil cooler, tighten it well.
Next align the plastic oil pipe First, if we can put it in and align the bolt #5 in place tighten a few turns, then we can start to align the right bottom #1 guide in place and also place bolt #1 in a few turn, by this time, we can push the whole cooler in flat and everything should line up perfectly. #5 bolt first, #1 bolt 2nd, #2 bolt 3rd, #3 bolt 4th and #4 bolt last. When every bolt has a few turns in them, start to tighten them diagonaly, middle one…
All 5 bolts are tight, place the 10mm bolt back to secure the black metal pipe. We are done with the oil cooler.