I've been posting on Audi FSI engines for some time now, and have discussed my oil analysis and issues with FSI engine fuel dilution impact on wear and deposit formation. Well, we now have confirmation of the oil-induced deposit formation issues with FSI engines.
Here's a direct quote from an RS4 owner who is also a Mechanical Engineer.
Quote:
A little over a month ago, had the car in for CEL, misfires, etc. They found bad injectors, replaced them and the car runs fine now. They also found the buildup on the intake valves that been talked about here. I was able to briefly look at it while they were cleaning them, but wasn't really able to inspect them. Well, I took the manifold off myself this weekend because I was bored and felt like wrenching on my car. It obvious from the intake ports and intake manifold that there is quite a bit of oil vapor in the intake air stream. Which is typical, especially on high performance engines. There is a light oily film on the manifold port (and flaps) leading directly into the cylinder head as well as in the port itself. The closer you get to the valves, the film is more tacky and in some places, almost hard. But not like dry flakes. IMO, the oil vapor entrained in the air stream just clings to the valves and sticks because the valves are relatively hot. Its not "carbon" buildup due to combustion, its oil film buildup thats not effectively cleaned by fuel since the engine is direct injected, not port injected. The RS4 has an elaborate crankcase ventilation system equipped with a 3-stage venturi cyclone to help remove the oil particles. Obviously it doesn't separate all the oil out. I don't think some buildup would be out of the ordinary on these engines. The valve in the pic was the worst and its been roughly 800 miles since the dealer cleaned them.
Quote:
After my $70k car's performance went down the gutter (the first oil change after the break in), I dug into it. I do various data logs almost every day. I plot the info and try to notice certain trends. After a while, things become clear but after you see your intake valves crudded up beyond belief and then in bad shape again only 800 miles later, it becomes obvious. The volatized oil creates buildup, which constantly breaks apart, which enters the combustion chamber, then adheres to injectors, which disrupts flow patterns and/or causes injector damage, which leads to poor economy and performance and fuel leakage into the chamber, that leads to cold start misfires and damaged coils. The buildup also drastically affects airflow into the engine. Dealers are good at replacing the coils, but bad at persisting to find what the root cause is. Its so ironic that the RS4 community thinks that my car is an exception just because I took the time to unveil an obvious problem. I would bet that 80% of them are having the same issues. Its really a shame, because the 4.2 FSI is going to get a bad wrap when its truly a masterpiece. I ordered 5gal of the RLI 5W40 and will be monitoring the intake valve buildup since I have no problem taking my manifold off to see what's going on.
IMO fuel dilution is the root cause for increased volatization and breakdown of the oil. 10 year oil Audi/VW formulations, designed to deal with engine sludge, do not stand up to fuel breakdown and end up as deposits on the valves, combustion chamber and injectors.
Here's a direct quote from an RS4 owner who is also a Mechanical Engineer.
Quote:
A little over a month ago, had the car in for CEL, misfires, etc. They found bad injectors, replaced them and the car runs fine now. They also found the buildup on the intake valves that been talked about here. I was able to briefly look at it while they were cleaning them, but wasn't really able to inspect them. Well, I took the manifold off myself this weekend because I was bored and felt like wrenching on my car. It obvious from the intake ports and intake manifold that there is quite a bit of oil vapor in the intake air stream. Which is typical, especially on high performance engines. There is a light oily film on the manifold port (and flaps) leading directly into the cylinder head as well as in the port itself. The closer you get to the valves, the film is more tacky and in some places, almost hard. But not like dry flakes. IMO, the oil vapor entrained in the air stream just clings to the valves and sticks because the valves are relatively hot. Its not "carbon" buildup due to combustion, its oil film buildup thats not effectively cleaned by fuel since the engine is direct injected, not port injected. The RS4 has an elaborate crankcase ventilation system equipped with a 3-stage venturi cyclone to help remove the oil particles. Obviously it doesn't separate all the oil out. I don't think some buildup would be out of the ordinary on these engines. The valve in the pic was the worst and its been roughly 800 miles since the dealer cleaned them.
Quote:
After my $70k car's performance went down the gutter (the first oil change after the break in), I dug into it. I do various data logs almost every day. I plot the info and try to notice certain trends. After a while, things become clear but after you see your intake valves crudded up beyond belief and then in bad shape again only 800 miles later, it becomes obvious. The volatized oil creates buildup, which constantly breaks apart, which enters the combustion chamber, then adheres to injectors, which disrupts flow patterns and/or causes injector damage, which leads to poor economy and performance and fuel leakage into the chamber, that leads to cold start misfires and damaged coils. The buildup also drastically affects airflow into the engine. Dealers are good at replacing the coils, but bad at persisting to find what the root cause is. Its so ironic that the RS4 community thinks that my car is an exception just because I took the time to unveil an obvious problem. I would bet that 80% of them are having the same issues. Its really a shame, because the 4.2 FSI is going to get a bad wrap when its truly a masterpiece. I ordered 5gal of the RLI 5W40 and will be monitoring the intake valve buildup since I have no problem taking my manifold off to see what's going on.
IMO fuel dilution is the root cause for increased volatization and breakdown of the oil. 10 year oil Audi/VW formulations, designed to deal with engine sludge, do not stand up to fuel breakdown and end up as deposits on the valves, combustion chamber and injectors.