Noticed a huge difference in engine oil after switching to a synthetic blend 3 months ago

I've been working on a 1998 Cessna 172 for the past few months and kept seeing the oil come out looking like sludge at every change. Switched over to a synthetic blend around April and this week's change looked almost clean. Still some color but nothing like before. Is this a common thing with older engines or did I just get lucky with this batch? Anyone else see big changes after switching oil types?

3 comments

3 Comments

dakota47913d ago

troy977's right, that cleaning action is no joke. I switched to synthetic blend in my old truck once and the first oil change after looked like a bad cup of coffee with extra grit. Guess my engine was just really good at hiding its dirty secrets from me.

troy97720d ago

Sometimes it's less about the oil itself and more about what the old oil was hiding. That sludge you saw before could have been built up varnish or deposits from years of cheap dino oil. The synthetic blend has better detergents, so it might be slowly cleaning out all that crud from inside the engine. Seen a few mechanics mention that on older airplane engines you might actually want to do a couple short oil changes after the switch to flush it all out, or else the loosened gunk can clog an oil screen or filter. Did you check your oil filter or screen when you did this last change?

anthonykim20d ago

Yeah, doing a couple quick changes after the switch really helped flush my engine out good.