Full synthetic swap was a waste on my old Honda

Everyone says switch to synthetic oil on older engines, but my 95 Civic with 180k started leaking from the rear main seal after I tried it. Swapped back to conventional and the drip stopped in a week. Anyone else have worse luck with synthetic on high mileage cars?

3 comments

3 Comments

mianelson1mo ago

So @juliarodriguez, how would you explain the rear main drying up and stopping after going back to conventional? That seems like more than just coincidence to me.

margaretramirez1mo ago

Did your buddy check if the synthetic was just thinner than what was in there before... My friend Tom put synthetic in his old Taurus and it started seeping from everywhere like a sieve.

juliarodriguez1mo ago

Pretty sure that's more of an old engine myth than anything real. @margaretramirez I've seen plenty of high mileage cars switch to synthetic and do just fine. Usually those leaks are from already worn out seals that would've given out anyway. The thinner oil might speed things up a tiny bit, but it's not gonna cause new leaks out of nowhere. Honestly, if your buddy's Taurus was that close to springing leaks, it was probably a matter of time regardless of what oil he used.