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

 

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!

 

my concern would be condensation from sitting. me personally i would get fresh stuff

 

The Mobil 1 is synthetic; it ought to be good, but I believe is would use it in the lawnmower.

Toss the Dexron just to be safe.

 

Oil doesn't go bad in a sealed container.

 

The oil itself should be good, MAYBE the additives could weaken, but I doubt it. Oil is stable or else it wouldn't last in a motor for months or underground since the dinosaurs.

 

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.

 

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.

 

Im not a rocket scientist. ( not even sure I can spell it? LOL) Many Years ago I took a college course in tech. Auto and I was told then that with conventional oil there are two different strand types that the companies start with. I can't remember exactly what the tech. names for these strands, but if Your running one brand of oil then add another brand to it or change to another brand. It is possible for the new oil to not cling to cylinder walls as the other oil is attached and the oil You have added will burn off by slipping past rings. This same Teacher claimed to have changed oil a race engine on our school dyno to synthetic and blew it out the exhaust in 10 or 15 mins. He said it was almost completely out of oil. I wasn't there at that time so I can't truely confirm it but He was an engineer for GM and has claimed to been involved in the design of the original LS7 454. So I have no reason to doubt Him. Just some extra useless information.

 

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.