Originally Posted by gleason99
i changed to T6 last November and after about 150 hours now my rear oil seal
is leaking. Coincidence? The engine
has about 4000 hours and I had been using normal non-synthetic Shell Rotella before this. Anybody have any thoughts on this?
Way back 30 or 40 years ago when synthetics first came out, that was always given as a reason to not use synthetic, it will make your engine
I’m sure decades before that when detergent oil
first came out, the same
thing was said, and there may be some truth in it, if your not so good at changing oil
then it’s likely that you get a coating of sludge in the engine and a good high detergent oil can clean things out, and your engine leaks
But also in this case the 5W oil is very thin at cold temps and will likely leak where a thicker 15W weight oil may not. Cold as in engine not warm, not meaning actual cold.
By the way Rotella T6 is now available as a 15W-40 oil also, which for most boats is likely to be a more applicable grade.
Synthetic oil will not make your engine leak, and yes an engine will also break in properly on synthetic oil, although many manufacturers still recommend against it for the first 500 hours or so, which goes to show me that manufacturers are not always a reliable source