Originally Posted By: buster
Have their been any tear downs or visual inspections of engine internals?
For intake valve deposits yes. Engines run on Audi-approved oils are a nasty mess, that takes 2 hours per cylinder to clean.
One owner who switched to Biosyn has performed several post oil change inspections by pulling the intake manifold. Here's his experience in his words:
Quote:
I’ll try to get the whole history as brief as possible. It’s lengthy, but hopefully informative. From the time the car was broken in, the cold starts were frequently rough and power delivery was erratic. The roughness should not be confused with a hunting or oscillating idle. It was caused by misfiring, as verified with Vagcom. It eventually got to the point when there would be 30-40 random misfires in the first 15 seconds. First oil change was at 4k by the dealer. By 8k miles, I had been in twice for “coil” issues to “correct” the CEL’s caused by the misfires. The coils were not the problem. The Service Mgr (not the SA, who was clueless) decided the fuel system should be checked. Four injectors failed the leak-down testing. Upon removing the intake to replace all 8 injectors at 8k miles, they discovered a disturbing amount of buildup on the intake valves. I saw the buildup, but did not take any photos. The dealer did a very good job of cleaning them and with the new injectors, the car ran much, much better. There have been no misfire issues since. I have hooked up Vagcom several times after the car has been sitting for 2-3 days and zero misfires are recorded – the engine fires up nicely, just as it should. The dealer used a fair amount of solvent when they cleaned the valves, so I changed oil at 8k, using the Castrol TXT synthetic available from the dealer. At 9k miles, I swapped in my ported intake. Low and behold, after only 1000 miles on a good 501/502 oil, the intake valve buildup was already at least 1/2 of what it was at 8k. I had figured that with good injectors that were no longer leaking fuel into the cylinders when the engine was off, there would less fuel dilution of the oil, less oil vapor in the crankcase air stream and much less buildup. Apparently not. So I cleaned the valves (major PITA), and decided to start using the RLI 5W-30 oil and fuel conditioner. At this point the car was running very strong. At 11.5k miles, I swapped in my version 2 ported manifold. After 2500 miles on the RLI oil, there was some buildup on the valves, but it was minimal. 500 miles later, I swapped manifolds again and of course the valve condition hadn’t changed much. The buildup rate is definitely slower with the RLI oil. So what have I learned? 1) The high performance nature of the RS4 engine means it volatizes a lot of oil, plain and simple 2) Generally speaking with FSI engines, rough cold starts and misfires are probably injector related – a bad coil would misfire all the time and minor valve buildup apparently doesn’t cause misfires 3) The injector problems are isolated and may be due to a manufacturing tolerance issue 4) I’ve used Tier 1 Shell fuel exclusively, it may keep the fuel system clean, but it does absolutely nothing for intake valve deposits on a FSI engine 4) A good fuel conditioner will help with maintaining clean injectors and minimizing combustion chamber deposits, but with a FSI engine, its affect on the intake valves is minimal 5) Oil chemistry can make a difference with the rate of buildup
