Switched to synthetic oil at 180k miles and the old engine runs worse now

I had a 2005 Silverado with 178k miles on it, ran on conventional 10w30 its whole life. Last month my buddy who works at a Jiffy Lube kept pushing me to swap to synthetic, said it was better for high mileage engines. I finally gave in at 180k miles. Within 2 weeks it started leaking oil from what looks like the rear main seal area. Never had a drop before. Now I'm wondering if the synthetic cleaned out all the old sludge that was plugging up the gaps. I'm thinking about draining it and going back to conventional. Has anyone else seen this happen on an older engine?

2 comments

2 Comments

ivan4017d ago

Man I've heard this exact story probably a dozen times. That synthetic oil didn't "clean out" anything, it's probably just thinner than the 10w30 you were running and found its way through a seal that was already dried out and cracked.

the_drew17d ago

Ha yeah fair point @ivan40! I guess my old truck's engine seals are as leaky as my ability to change oil on time. At least it's a good excuse to finally check that valve cover gasket I've been ignoring.