It seems like turbo engines are more likely to have oil dilution problems than naturally aspirated engines. It also seems like oil change intervals have gone from the industry standard 3,000 miles to 5K, 10K, or even 15K miles!
Historically, have there been any naturally aspirated engines with oil dilution problems? Or is it mainly a turbo phenomena?
Also, given the greater oil change intervals, could oil dilution have gone UNDETECTED for so long in any car, because the oil interval change was so frequent?
I have a 1999 Audi A6 (1.8T) with over 250,000km (yes they exist), dealership says that I should change my oil at 7000 km (4350 miles), but I do mine much sooner at around 3000 km (1864 miles), just to be safe. The engine is still strong.
It's a combination of GDI (gasoline direct injection) plus turbocharging on small displacement engines that causes the problem. I've never heard of pre-GDI turbocharged engines experiencing oil dilution, nor have I experienced it in any of my older turbos.
You won't hurt anything by changing the oil that frequently but realistically 4000-5000 miles is really OK. We used to do 1000-2000 mile oil changes way back when oil was lousy and engines didn't always have oil filters but today it's overkill.
I am curious, why does GDI contribute to oil dilution vs port injection?
Probably because it is spraying gasoline under high pressure directly into the cylinders. The effect seems to be worse on small-displacement engines.
GDI has a high-pressure fuel pump. More pressure = More power baby = more dilution and problems.
OIC. I was under the impression it was just directly injected, but I can see oil dilution happening with higher pressure.