Long overdue update - finally got around to doing the carbon cleaning + JHM intake manifold spacer installation over some time off for the holidays. Great success and worth taking the time to do. On the first test drive yesterday, everything went great. Throttle feels slightly more responsive and the exhaust note sounds “throatier”. Most importantly, is the peace of mind in doing the service. When you do it yourself, you can be as meticulous as you want. There was also a ton of carbon on the valves, and I am confident that this was a good use of time and effort. The car has 96,000 miles on the clock I am the third owner. Unsure of the carbon cleaning history with the original owner, but I confirmed with the prior owner that he did not do carbon cleaning.
Big thank you to all of the info posted by CountVohn and Justincredible from all the other forum posts - following those directions I was able to take care of all the small details and it really set me up for success.
While removing everything to get to the valves, I observed my pcv oil separator that leads to the intake was covered in oil - must have cracked somewhere. I replaced with a new one.
I broke the big breather hose that connects the valve covers to the oil separator when taking it off. I was gentle, but that plastic is brittle! I replaced/rebuilt with oil/fuel rated hose.
I also had oil dripping down the front since ownership, not a lot but enough to make me suspect the oil filter housing figure 8 o ring. I replaced this and was glad I did - lots of oil in the valley and the o ring was as hard and brittle as a rock. The old one was longer providing a good seal, but it is now taken care of.
For the cleaning itself:
I did a chemical clean with oven cleaner. As suggested, I pulled the coils/plugs and filled the valves I thought were closed with starter fluid. After 10 minutes or so and no drop in fluid, I masked off the other valves and got to work. I would start by picking out the big carbon bits and using the shop vac, then proceeded with soaking, brushing, scraping, vacuuming, compressed air, repeat. I was not a big fan of the zip tie in the drill, was very messy and the zip ties did not last long. I mostly used the metal picks, brush, and of course oven cleaner. I also made sure to mask off the fuel injector lines where exposed, spark plug wells, etc. No mater what you do you will make a mess, so try to protect areas of entry. When I was done I flushed each valve with windshield washer fluid. I also did not reinstall the port divider plates - left those out of the car.
During the cleaning I was literally shoveling out carbon behind the valve stems, not sure how a walnut blast would get up in there. I did the actual cleaning over the course of 3 days - I was not in a rush and took my time, and my garage was pretty cold her in MN. It took quite a few cleanings per valve to get them to where I was happy, but overall this is a great process for the DIY’er.
After doing all the valves, I ran the starter to purge out anything that could have somehow ended up in the cylinders. To do this I of course had the spark plugs removed, but I disconnected the fuel pump relay in the trunk (passenger side near the battery). Relay number is: 614
(I had removed this relay before I started to disconnect the fuel lines just to make sure that opening the door would not spray fuel all over the engine bay over the course of my cleaning).
The money shots:
Other notes:
My intake manifold flaps all work and are in great condition! I feel very fortunate.
When pulling the spark plugs I had quite a few on the passenger side that had oil on the spark plugs, and a few on the drivers side. I am thinking at some point in my future I will be doing valve cover gasket replacements.
Installed the JHM intake spacers and everything went in smoothly. I feel confident that I am setting myself up for less issues down the road by using these. I installed the gaskets above and below the spacers, but for the sake of the picture here I left the top gasket off to show off the cool looking spacers.
I did not do the JHM heater hose bypass as I live in MN. This winter has been mild, but some years it gets very, very cold. Question here: would it still be worth doing the hose bypass, or leave it stock? What do others in very cold climates recommend? It seems counter intuitive to heat up the blowby gasses with the coolant, while trying to keep these gases colder with the spacers, so I am really leaning towards bypass, but really need cold weather reliability. Along the same vein - what is recommended regarding the SAI in cold weather climates? Leave stock or delete?
Next items: Previous owner had the fuel injectors pulled and cleaned, I want to keep them that way. I plan on using BG Platinum 44k fuel injector cleaner in the next week or so, and then an oil change. Has anybody used this cleaner? I have read that it is recommended to do an oil change after using it.
I have read good things about it and plan to do it before every oil change.
For every / every other fill up at the pump, what are your favorite “normal” fuel injector cleaners to use?
What oil / filters is everybody using?
I have used mobile 1 0w40 for my 2001 B5 S4, and was leaning towards their 5w40 Europeans formula for the S8. What is everybody else here using? Any recommendations for MN climate?
Do you all prefer servicing the oil by draining, or by extracting from the top. I have done both on other audi’s and honestly prefer the top. I may have to get a bigger extractor to account for all the oil in the v10!
Other updates:
The speaker repair was a big success, no more crackling and beautiful sounds coming from the speakers. I would highly recommend replacing the surrounds if you have this issue.
I recently had the windows tinted with xpel 50% to keep it MN legal. I like the subtle smoky tint and the OEM+ look. It also keeps all the UV and heat out which is awesome for comfort and no UV damage to skin. Here are some pictures in the same parking lot on different days. Some in the sun, one with our gloomy winter weather. The winter picture is sporting some OEM Audi takeoff wheels and new Nokian R5 winter tires. I plastidipped the wheels and used an aluminum metalizer to hide some rash and keep them looking fresh without a full refurb.
All three pictures are with the tint:
Not sure what the future holds, perhaps at some point ECU/TCU tune…for now I am going to keep enjoying the car as is!
Thanks for reading, and thank you for all of the advice that has been offered on these boards!
). I am looking forward to enjoying each car for what they were built for. My current goals for the S8 are very simple. I want to refresh and maintain a reliable long distance commuter / road trip machine.
I am planning on getting the equipment to walnut blast it myself. While I am in there I would like to inspect the manifold flaps and install JHM Spacers.
