oil mixup =(

[TDWPgtp]

so i managed to purchase and put in 2 quarts of the right oil (10w30) and 2 quarts of the wrong oil (5w20). now i dont feel like changing it all and buying new oil again so i was wondering if this mix is ok to drive with. does it actually make that big of a difference or will i be ok until the next oil change comes around? thanks in advance

[tblake]

5w20 is pretty thin stuff.

But 2 plus 2 doesn't add up. Oil capacity on a 3800 after a filter change is 4.5 quarts. Do you have the right amount in there?

[MagicRat]

From what I have read, a mix of otherwise-compatible oils will result in a weight that is approximately proportional, in this case, about 7.5 W 30.

IMO if you really care about the car, drain it and put the right stuff in. If you drain into a clean container, the old oil can be reused in stuff that is not so important, like lawnmowers etc.

If this were wintertime, I would say just leave the thin stuff in there, but in summer the extra viscosity is useful.

[jakegday]

Originally Posted by MagicRat

From what I have read, a mix of otherwise-compatible oils will result in a weight that is approximately proportional, in this case, about 7.5 W 30.
.

shouldnt it be 7.5w25?

if it were me, i MIGHT let it stay in if it was winter. right now though, not a chance. im not saying it will hurt anything, but oils cheap, i personally would just sleep better at night

[TDWPgtp]

Originally Posted by tblake

5w20 is pretty thin stuff.

But 2 plus 2 doesn't add up. Oil capacity on a 3800 after a filter change is 4.5 quarts. Do you have the right amount in there?

oo wow. at some point, a mechanic wrote 4.0 quarts near the oil cap, so i assumed thats what it took. ill make sure to put in 4.5 though. and i guess ill change it all again since everyone seems to have the same opinion.

i wasnt sure because the guys in the machine shop at my dads work said that it shouldnt really make a difference over such a short change interval.

[BNaylor]

There is no problem mixing the two different multi-viscosity oils stated. The alternate oil for a Series II 3800 engine is 5W-30 so the 5W-20 is close enough. You are not supposed to use oil like 20W-50.

GM has gone to 5W-30 in just about all their V6 and V8 engines now.

Also, gentlemen the oil capacity is and always has been 4.5 quarts with filter change as Tim stated.