My truck leaks drips oil every now and then and is getting low. The oil in there only has about 1000 miles on it, so I would just like to add more.
Problem is I don't know which oil I put in there before.

If I get new oil that's different, is it ok to mix it with the unknown oil in there now?

I've never had any particular problem with it as long as the weight's the same and the detergent rating isn't higher.

In other words, if you used 10w30 use 10w30 or 5w30.

This post was edited by gusdidit on Jul 21 2013 11:40am

i would put the manufacturers recommeded oil in there. it should be close enough to what you have in it. as long as its close its not going to hurt it. and with 1k miles and its low enough to need more added id say its more than just a drip every now and then



he doesnt remember what he put in it last time thats why hes asking if its not the exact same would it be fine.

Where would I find the manufacturer recommended oil? It's a 50 year old truck...

I guess I'll just change my oil and buy and extra quart of the oil I get.

easiest option

what kind of truck and what motor you got in it? off the top of my head i would go with 10w30

and if youre that worried then yes just change the oil. i would get the leak fixed though if its that bad.

This post was edited by JDH on Jul 21 2013 12:07pm

1964 C10 with the 236 I6

just change it and put some regular dino oil in there. Don't put synthetic in a 50 year old truck.

What's the benefit of using non-synthetic?

It was raised on non-synthetic. All the sludge in there is non-synthetic. The general theory is that synthetic oil and dinosaur oil don't mix properly and can cause clogging problems down the road.