Another oil question!!!

[cchuffman]

So a buddy of mine just bought a house that came with a tool shed. Per the terms of the sale, the contents of the shed came with the house. Most of what we found was old tools and a lot of trash. But we did come along a case of synthetic blend Castrol motor oil (10w30). It's hard to say how old it is, but none of the bottles have been opened. This leads to the obvious question ... is this oil still good? Would anyone here use it not knowing it's age, and could it do any damage to my Envoy if I did? I would appreciate any insight you may have.

 

[MacMan]

Recommended oil for this engine is 5w-30, but it can use the 10w-30 in a pinch. If the containers are factory sealed, and have the API starburst symbol, it can be used.

 

[Wooluf1952]

Just a thought: Would mixing 3.5 quarts of 10w-30 and 3.5 qts of 0w-30 make it the same as 5w-30?


cchuffman: How often do you change your oil?
If you only used it in the summer heat it should be OK. I'd still mix it 50/50, but that's just me.

 

[MacMan]

Just a thought: Would mixing 3.5 quarts of 10w-30 and 3.5 qts of 0w-30 make it the same as 5w-30?.....

Yes, theoretically.

 

[cchuffman]

cchuffman: How often do you change your oil?
If you only used it in the summer heat it should be OK. I'd still mix it 50/50, but that's just me.

I change my oil every 3,000 miles. Even if I put the 10w30 in it now, I'm sure I'd be changing it agian before the coldest part of winter. I would put 5w30 in it then. Whether I use it or not isn't a big deal. I just don't want to see the oil go to waste.

I'm also cheap ... that is probably the greatest driving force in all of this.

 

[The_Roadie]

I change my oil every 3,000 miles....

I'm also cheap ...

Those two statements are inconsistent. Why not trust the Oil Life Monitoring system and safely stretch that interval closer to 10K? Surely you didn't buy into the Jiffy-Lube marketing lies? Self-serving crooks, they are. Greedy anti-environmentalists. :banghead:

 

[cchuffman]

Let me correct myself ...
I like to change my oil every 3,000 miles because that is what my dad taught me when I was a kid. Of course, that was on a 1980 Oldsmobile station wagon. So maybe that isn't the best baromater to use.
And maybe "cheap" wasn't the right word to use. I'm budget-conscious.

 

[Denali n DOO]

Let me correct myself ...
I like to change my oil every 3,000 miles because that is what my dad taught me when I was a kid. Of course, that was on a 1980 Oldsmobile station wagon. So maybe that isn't the best baromater to use.
And maybe "cheap" wasn't the right word to use. I'm budget-conscious.

I use to use the OLM, a new 5.3 engine later and I'm back to 5000km changes. I think the shorter interval is better. And I wouldn't use oil that wasn't recommended like 10w30 or try mixing oils to create a 5w30. Just my 2 cents.