Using old oils
Thread Starter
Burning Brakes
Joined: Jun 2008
Posts: 1,094
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From: NYC - HK
Using old oils
Sorry for the n00b question, but can you use old oil that hasnt been used before? Found some old but still sealed mobil 1 and dexron ATF that's probably from the 1990's in my dad's garage and was wondering if it's still usable. Not trying to cheap out or anything but just curious. Also what's the difference between all the different Dexron ATFs? TIA 
Melting Slicks
Joined: Mar 2007
Posts: 2,100
Likes: 12
From: Frederick Maryland
It's usable...for cars of that period. It won't meet the specs for current cars. I doubt of there's any issues using it in a C3 with its vintage engine.
How much do you have...enough for a full oil change or less? For a complete oil change it probably would be fine...I wouldn't mix it with current spec oils. It probably wouldn't hurt anything but just doesn't seem the best thing to do.
As far as the ATF...as long as it goes into a transmission designed for the specs of it, I don't think it would be a problem.
It's your money!
How much do you have...enough for a full oil change or less? For a complete oil change it probably would be fine...I wouldn't mix it with current spec oils. It probably wouldn't hurt anything but just doesn't seem the best thing to do.
As far as the ATF...as long as it goes into a transmission designed for the specs of it, I don't think it would be a problem.
It's your money!
Thread Starter
Burning Brakes
Joined: Jun 2008
Posts: 1,094
Likes: 0
From: NYC - HK
Thanks for the replies guys. I was planning on dumping the stuff anyway but my dad told me that I'm wasting it. Anyway, better safe than sorry. Would never cheap out on something that's only a few bucks. 
Intermediate
Joined: Jul 2010
Posts: 44
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I wouldn't mix it with current spec oils. It probably wouldn't hurt anything but just doesn't seem the best thing to do.
Oil is already a fairly sloppy mixture, not a homogenous compound (maybe synthetics are, that is one reason why they are so good), so unless there is a reaction between one oil and another I would always (for the past 30 years) mix anything with anything else. I have always just 'added a quart' of something or other to a motor. Regular dino oil to synthetic, even marvel mystery to dino, mobil 1 to amsoil, arco graphite to wolfshead, I think all these things are Ok to mix unless you have different chemistries like ATF or gear oil or brake fkuid. There is slick 50, prolong, stp, zddp, marvel, and dozens of ther additives that ALL can't be tested on ALL oils or basestocks. My guess is it all works OK together and that given how good today's oil (and additives) is compared to oil from the 60s that any of it now is better than any of it then but all of it can work together. There are even synthetic/dino blends sold, so that seems to work too.
My first degree was chemical engineering, but this stuff wasn't my speciality (I make rockets and stuff) so I could easily be wrong, is there hard data out there? Thanks.
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Burning Brakes
Joined: May 2008
Posts: 860
Likes: 0
From: Stratford Ontario
After thinking about it, I can't imagine why it would matter unless one oil would coagulate another, which probably won't/can't happen.
Oil is already a fairly sloppy mixture, not a homogenous compound (maybe synthetics are, that is one reason why they are so good), so unless there is a reaction between one oil and another I would always (for the past 30 years) mix anything with anything else. I have always just 'added a quart' of something or other to a motor. Regular dino oil to synthetic, even marvel mystery to dino, mobil 1 to amsoil, arco graphite to wolfshead, I think all these things are Ok to mix unless you have different chemistries like ATF or gear oil or brake fkuid. There is slick 50, prolong, stp, zddp, marvel, and dozens of ther additives that ALL can't be tested on ALL oils or basestocks. My guess is it all works OK together and that given how good today's oil (and additives) is compared to oil from the 60s that any of it now is better than any of it then but all of it can work together. There are even synthetic/dino blends sold, so that seems to work too.
My first degree was chemical engineering, but this stuff wasn't my speciality (I make rockets and stuff) so I could easily be wrong, is there hard data out there? Thanks.
Oil is already a fairly sloppy mixture, not a homogenous compound (maybe synthetics are, that is one reason why they are so good), so unless there is a reaction between one oil and another I would always (for the past 30 years) mix anything with anything else. I have always just 'added a quart' of something or other to a motor. Regular dino oil to synthetic, even marvel mystery to dino, mobil 1 to amsoil, arco graphite to wolfshead, I think all these things are Ok to mix unless you have different chemistries like ATF or gear oil or brake fkuid. There is slick 50, prolong, stp, zddp, marvel, and dozens of ther additives that ALL can't be tested on ALL oils or basestocks. My guess is it all works OK together and that given how good today's oil (and additives) is compared to oil from the 60s that any of it now is better than any of it then but all of it can work together. There are even synthetic/dino blends sold, so that seems to work too.
My first degree was chemical engineering, but this stuff wasn't my speciality (I make rockets and stuff) so I could easily be wrong, is there hard data out there? Thanks.
Intermediate
Joined: Jul 2010
Posts: 44
Likes: 0
http://www.citgo.com/ConsumerProduct...neOilMyths.jsp
Citgo claims you can mix. Not to beat a dead horse, but Mobil agrees.
https://www.mobiloil.com/USA-English...tion.aspx?pg=2
It really only makes sense, it is just oil. We tend to think too much about dumb crap like this.
Citgo claims you can mix. Not to beat a dead horse, but Mobil agrees.
https://www.mobiloil.com/USA-English...tion.aspx?pg=2
It really only makes sense, it is just oil. We tend to think too much about dumb crap like this.
