Old & New Oil Don't Mix !

Joined
Feb 3, 2006
Messages
9,103
Location
MN
Ok, get this: I drained the oil out of my 140Hp 4-stroke outboard last fall, changed the filter, filled it up with Dino amd it has sat since last October. It had about 80 hours of hard run time in 'er. So, I see that Amsoil has a newer 4-stroke outboard oil that's way better than regular dino. Couldn't run the dino this year knowing a much better oil is out there, so I got the Amsoil and drained out the "Fresh" oil out. [Big Grin] Well, first about a 1/4 cup of dirty oil came out then all the the fresh oil came out into the drain pan. Hummm... Here's the interesting part: [Smile] The dirty oil "kept separated" at the bottom corner of the drain pan and did not mix at all with the fresh oil ! I moved aroung the drain pan at angles and it stayed separated. Here I thought it would mix some, but no go... (By the way, I'm keeping the "fresh" oil for something else in the future...) Has anyone else seen or tried this ? [Cheers!]
 

oli

Joined
Jun 4, 2005
Messages
61
Location
new england
Assuming it is moisture related, I would not assume that ALL of this moisture was in the old oil. So it is not an issue of old and new oil not mixing, it is an issue of moisture not mixing. Put the container up on a bench and siphon off the top "clean" oil to get a better look at what is left on the bottom. Then put the bottom stuff in a clear container so you can see it up close.
 

Turk

Thread starter
Joined
Feb 3, 2006
Messages
9,103
Location
MN
Since it is an outboard, maybe there was a tiny amount of water mixed in, which scares me [Eek!] , but I think it is just the amount of dirt in it. 2nd year of running the Suzuki by the way... Wouldn't the water separate from the old oil ? Or wouldn't it be a cloudy brown ? [I dont know]
 

Turk

Thread starter
Joined
Feb 3, 2006
Messages
9,103
Location
MN
Since it is an outboard, maybe there was a tiny amount of water mixed in, which scares me [Eek!] , but I think it is just the amount of dirt in it. 2nd year of running the Suzuki by the way... Wouldn't the water separate from the old oil ? Or wouldn't it be a cloudy brown ? [I dont know]
 

oli

Joined
Jun 4, 2005
Messages
61
Location
new england
I've never changed the oil in anything without the oil being warm and I always run the motor immediately afterwards. The "running" part would be especially important prior to long term storage to coat all engine parts in fresh oil. That is the main reason for changing the oil prior to storage.
 
Top